aboutsummaryrefslogtreecommitdiffstats
path: root/common/nextpnr.h
blob: 66bba9975b1c82021df694cd8a2252c56d5cf90e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
/*
 *  nextpnr -- Next Generation Place and Route
 *
 *  Copyright (C) 2018  Clifford Wolf <clifford@symbioticeda.com>
 *  Copyright (C) 2018  Serge Bazanski <q3k@symbioticeda.com>
 *
 *  Permission to use, copy, modify, and/or distribute this software for any
 *  purpose with or without fee is hereby granted, provided that the above
 *  copyright notice and this permission notice appear in all copies.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

#include <algorithm>
#include <assert.h>
#include <condition_variable>
#include <memory>
#include <mutex>
#include <stdexcept>
#include <stdint.h>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#include <boost/functional/hash.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/range/adaptor/reversed.hpp>
#include <boost/thread.hpp>

#ifndef NEXTPNR_H
#define NEXTPNR_H

#ifdef NEXTPNR_NAMESPACE
#define NEXTPNR_NAMESPACE_PREFIX NEXTPNR_NAMESPACE::
#define NEXTPNR_NAMESPACE_BEGIN namespace NEXTPNR_NAMESPACE {
#define NEXTPNR_NAMESPACE_END }
#define USING_NEXTPNR_NAMESPACE using namespace NEXTPNR_NAMESPACE;
#else
#define NEXTPNR_NAMESPACE_PREFIX
#define NEXTPNR_NAMESPACE_BEGIN
#define NEXTPNR_NAMESPACE_END
#define USING_NEXTPNR_NAMESPACE
#endif

#if defined(__GNUC__) || defined(__clang__)
#define NPNR_ATTRIBUTE(...) __attribute__((__VA_ARGS__))
#define NPNR_NORETURN __attribute__((noreturn))
#define NPNR_DEPRECATED __attribute__((deprecated))
#define NPNR_PACKED_STRUCT(...) __VA_ARGS__ __attribute__((packed))
#elif defined(_MSC_VER)
#define NPNR_ATTRIBUTE(...)
#define NPNR_NORETURN __declspec(noreturn)
#define NPNR_DEPRECATED __declspec(deprecated)
#define NPNR_PACKED_STRUCT(...) __pragma(pack(push, 1)) __VA_ARGS__ __pragma(pack(pop))
#else
#define NPNR_ATTRIBUTE(...)
#define NPNR_NORETURN
#define NPNR_DEPRECATED
#define NPNR_PACKED_STRUCT(...) __VA_ARGS__
#endif

NEXTPNR_NAMESPACE_BEGIN

class assertion_failure : public std::runtime_error
{
  public:
    assertion_failure(std::string msg, std::string expr_str, std::string filename, int line);

    std::string msg;
    std::string expr_str;
    std::string filename;
    int line;
};

NPNR_NORETURN
inline void assert_fail_impl(const char *message, const char *expr_str, const char *filename, int line)
{
    throw assertion_failure(message, expr_str, filename, line);
}

NPNR_NORETURN
inline void assert_fail_impl_str(std::string message, const char *expr_str, const char *filename, int line)
{
    throw assertion_failure(message, expr_str, filename, line);
}

#define NPNR_ASSERT(cond) (!(cond) ? assert_fail_impl(#cond, #cond, __FILE__, __LINE__) : (void)true)
#define NPNR_ASSERT_MSG(cond, msg) (!(cond) ? assert_fail_impl(msg, #cond, __FILE__, __LINE__) : (void)true)
#define NPNR_ASSERT_FALSE(msg) (assert_fail_impl(msg, "false", __FILE__, __LINE__))
#define NPNR_ASSERT_FALSE_STR(msg) (assert_fail_impl_str(msg, "false", __FILE__, __LINE__))

struct BaseCtx;
struct Context;

struct IdString
{
    int index;

    static void initialize_arch(const BaseCtx *ctx);

    static void initialize_add(const BaseCtx *ctx, const char *s, int idx);

    constexpr IdString(int index = 0) : index(index) {}

    void set(const BaseCtx *ctx, const std::string &s);

    IdString(const BaseCtx *ctx, const std::string &s) { set(ctx, s); }

    IdString(const BaseCtx *ctx, const char *s) { set(ctx, s); }

    const std::string &str(const BaseCtx *ctx) const;

    const char *c_str(const BaseCtx *ctx) const;

    bool operator<(const IdString &other) const { return index < other.index; }

    bool operator==(const IdString &other) const { return index == other.index; }

    bool operator!=(const IdString &other) const { return index != other.index; }

    bool empty() const { return index == 0; }
};

NEXTPNR_NAMESPACE_END

namespace std {
template <> struct hash<NEXTPNR_NAMESPACE_PREFIX IdString>
{
    std::size_t operator()(const NEXTPNR_NAMESPACE_PREFIX IdString &obj) const noexcept
    {
        return std::hash<int>()(obj.index);
    }
};
} // namespace std

NEXTPNR_NAMESPACE_BEGIN

struct GraphicElement
{
    enum type_t
    {
        TYPE_NONE,
        TYPE_LINE,
        TYPE_ARROW,
        TYPE_BOX,
        TYPE_CIRCLE,
        TYPE_LABEL,

        TYPE_MAX
    } type = TYPE_NONE;

    enum style_t
    {
        STYLE_GRID,
        STYLE_FRAME,    // Static "frame". Contrast between STYLE_INACTIVE and STYLE_ACTIVE
        STYLE_HIDDEN,   // Only display when object is selected or highlighted
        STYLE_INACTIVE, // Render using low-contrast color
        STYLE_ACTIVE,   // Render using high-contast color

        // UI highlight groups
        STYLE_HIGHLIGHTED0,
        STYLE_HIGHLIGHTED1,
        STYLE_HIGHLIGHTED2,
        STYLE_HIGHLIGHTED3,
        STYLE_HIGHLIGHTED4,
        STYLE_HIGHLIGHTED5,
        STYLE_HIGHLIGHTED6,
        STYLE_HIGHLIGHTED7,

        STYLE_SELECTED,
        STYLE_HOVER,

        STYLE_MAX
    } style = STYLE_FRAME;

    float x1 = 0, y1 = 0, x2 = 0, y2 = 0, z = 0;
    std::string text;
    GraphicElement(){};
    GraphicElement(type_t type, style_t style, float x1, float y1, float x2, float y2, float z)
            : type(type), style(style), x1(x1), y1(y1), x2(x2), y2(y2), z(z){};
};

struct Loc
{
    int x = -1, y = -1, z = -1;

    Loc() {}
    Loc(int x, int y, int z) : x(x), y(y), z(z) {}

    bool operator==(const Loc &other) const { return (x == other.x) && (y == other.y) && (z == other.z); }
    bool operator!=(const Loc &other) const { return (x != other.x) || (y != other.y) || (z != other.z); }
};

struct ArcBounds
{
    int x0 = -1, y0 = -1, x1 = -1, y1 = -1;

    ArcBounds() {}
    ArcBounds(int x0, int y0, int x1, int y1) : x0(x0), y0(y0), x1(x1), y1(y1){};

    int distance(Loc loc) const
    {
        int dist = 0;
        if (loc.x < x0)
            dist += x0 - loc.x;
        if (loc.x > x1)
            dist += loc.x - x1;
        if (loc.y < y0)
            dist += y0 - loc.y;
        if (loc.y > y1)
            dist += loc.y - y1;
        return dist;
    };
};

struct TimingConstrObjectId
{
    int32_t index = -1;

    bool operator==(const TimingConstrObjectId &other) const { return index == other.index; }
    bool operator!=(const TimingConstrObjectId &other) const { return index != other.index; }
};

NEXTPNR_NAMESPACE_END

namespace std {
template <> struct hash<NEXTPNR_NAMESPACE_PREFIX Loc>
{
    std::size_t operator()(const NEXTPNR_NAMESPACE_PREFIX Loc &obj) const noexcept
    {
        std::size_t seed = 0;
        boost::hash_combine(seed, hash<int>()(obj.x));
        boost::hash_combine(seed, hash<int>()(obj.y));
        boost::hash_combine(seed, hash<int>()(obj.z));
        return seed;
    }
};

template <> struct hash<NEXTPNR_NAMESPACE_PREFIX TimingConstrObjectId>
{
    std::size_t operator()(const NEXTPNR_NAMESPACE_PREFIX TimingConstrObjectId &obj) const noexcept
    {
        return hash<int>()(obj.index);
    }
};

} // namespace std

#include "archdefs.h"

NEXTPNR_NAMESPACE_BEGIN

struct DecalXY
{
    DecalId decal;
    float x = 0, y = 0;

    bool operator==(const DecalXY &other) const { return (decal == other.decal && x == other.x && y == other.y); }
};

struct BelPin
{
    BelId bel;
    IdString pin;
};

struct CellInfo;

struct Region
{
    IdString name;

    bool constr_bels = false;
    bool constr_wires = false;
    bool constr_pips = false;

    std::unordered_set<BelId> bels;
    std::unordered_set<WireId> wires;
    std::unordered_set<Loc> piplocs;
};

enum PlaceStrength
{
    STRENGTH_NONE = 0,
    STRENGTH_WEAK = 1,
    STRENGTH_STRONG = 2,
    STRENGTH_FIXED = 3,
    STRENGTH_LOCKED = 4,
    STRENGTH_USER = 5
};

struct PortRef
{
    CellInfo *cell = nullptr;
    IdString port;
    delay_t budget = 0;
};

struct PipMap
{
    PipId pip = PipId();
    PlaceStrength strength = STRENGTH_NONE;
};

struct Property
{
    enum State : char
    {
        S0 = '0',
        S1 = '1',
        Sx = 'x',
        Sz = 'z'
    };

    Property();
    Property(int64_t intval, int width = 32);
    Property(const std::string &strval);
    Property(State bit);
    Property &operator=(const Property &other) = default;

    bool is_string;

    // The string literal (for string values), or a string of [01xz] (for numeric values)
    std::string str;
    // The lower 64 bits (for numeric values), unused for string values
    int64_t intval;

    void update_intval()
    {
        intval = 0;
        for (int i = 0; i < int(str.size()); i++) {
            NPNR_ASSERT(str[i] == S0 || str[i] == S1 || str[i] == Sx || str[i] == Sz);
            if ((str[i] == S1) && i < 64)
                intval |= (1ULL << i);
        }
    }

    int64_t as_int64() const
    {
        NPNR_ASSERT(!is_string);
        return intval;
    }
    std::vector<bool> as_bits() const
    {
        std::vector<bool> result;
        result.reserve(str.size());
        NPNR_ASSERT(!is_string);
        for (auto c : str)
            result.push_back(c == S1);
        return result;
    }
    std::string as_string() const
    {
        NPNR_ASSERT(is_string);
        return str;
    }
    const char *c_str() const
    {
        NPNR_ASSERT(is_string);
        return str.c_str();
    }
    size_t size() const { return is_string ? 8 * str.size() : str.size(); }
    double as_double() const
    {
        NPNR_ASSERT(is_string);
        return std::stod(str);
    }
    bool as_bool() const
    {
        if (int(str.size()) <= 64)
            return intval != 0;
        else
            return std::any_of(str.begin(), str.end(), [](char c) { return c == S1; });
    }
    bool is_fully_def() const
    {
        return !is_string && std::all_of(str.begin(), str.end(), [](char c) { return c == S0 || c == S1; });
    }
    Property extract(int offset, int len, State padding = State::S0) const
    {
        Property ret;
        ret.is_string = false;
        ret.str.reserve(len);
        for (int i = offset; i < offset + len; i++)
            ret.str.push_back(i < int(str.size()) ? str[i] : padding);
        ret.update_intval();
        return ret;
    }
    // Convert to a string representation, escaping literal strings matching /^[01xz]* *$/ by adding a space at the end,
    // to disambiguate from binary strings
    std::string to_string() const;
    // Convert a string of four-value binary [01xz], or a literal string escaped according to the above rule
    // to a Property
    static Property from_string(const std::string &s);
};

inline bool operator==(const Property &a, const Property &b) { return a.is_string == b.is_string && a.str == b.str; }
inline bool operator!=(const Property &a, const Property &b) { return a.is_string != b.is_string || a.str != b.str; }

struct ClockConstraint;

struct NetInfo : ArchNetInfo
{
    IdString name, hierpath;
    int32_t udata = 0;

    PortRef driver;
    std::vector<PortRef> users;
    std::unordered_map<IdString, Property> attrs;

    // wire -> uphill_pip
    std::unordered_map<WireId, PipMap> wires;

    std::vector<IdString> aliases; // entries in net_aliases that point to this net

    std::unique_ptr<ClockConstraint> clkconstr;

    TimingConstrObjectId tmg_id;

    Region *region = nullptr;
};

enum PortType
{
    PORT_IN = 0,
    PORT_OUT = 1,
    PORT_INOUT = 2
};

struct PortInfo
{
    IdString name;
    NetInfo *net;
    PortType type;
    TimingConstrObjectId tmg_id;
};

struct CellInfo : ArchCellInfo
{
    IdString name, type, hierpath;
    int32_t udata;

    std::unordered_map<IdString, PortInfo> ports;
    std::unordered_map<IdString, Property> attrs, params;

    BelId bel;
    PlaceStrength belStrength = STRENGTH_NONE;

    // cell_port -> bel_pin
    std::unordered_map<IdString, IdString> pins;

    // placement constraints
    CellInfo *constr_parent = nullptr;
    std::vector<CellInfo *> constr_children;
    const int UNCONSTR = INT_MIN;
    int constr_x = UNCONSTR;   // this.x - parent.x
    int constr_y = UNCONSTR;   // this.y - parent.y
    int constr_z = UNCONSTR;   // this.z - parent.z
    bool constr_abs_z = false; // parent.z := 0
    // parent.[xyz] := 0 when (constr_parent == nullptr)

    Region *region = nullptr;
    TimingConstrObjectId tmg_id;

    void addInput(IdString name);
    void addOutput(IdString name);
    void addInout(IdString name);

    void setParam(IdString name, Property value);
    void unsetParam(IdString name);
    void setAttr(IdString name, Property value);
    void unsetAttr(IdString name);
};

enum TimingPortClass
{
    TMG_CLOCK_INPUT,     // Clock input to a sequential cell
    TMG_GEN_CLOCK,       // Generated clock output (PLL, DCC, etc)
    TMG_REGISTER_INPUT,  // Input to a register, with an associated clock (may also have comb. fanout too)
    TMG_REGISTER_OUTPUT, // Output from a register
    TMG_COMB_INPUT,      // Combinational input, no paths end here
    TMG_COMB_OUTPUT,     // Combinational output, no paths start here
    TMG_STARTPOINT,      // Unclocked primary startpoint, such as an IO cell output
    TMG_ENDPOINT,        // Unclocked primary endpoint, such as an IO cell input
    TMG_IGNORE,          // Asynchronous to all clocks, "don't care", and should be ignored (false path) for analysis
};

enum ClockEdge
{
    RISING_EDGE,
    FALLING_EDGE
};

struct TimingClockingInfo
{
    IdString clock_port; // Port name of clock domain
    ClockEdge edge;
    DelayInfo setup, hold; // Input timing checks
    DelayInfo clockToQ;    // Output clock-to-Q time
};

struct ClockConstraint
{
    DelayInfo high;
    DelayInfo low;
    DelayInfo period;

    TimingConstrObjectId domain_tmg_id;
};

struct TimingConstraintObject
{
    TimingConstrObjectId id;
    enum
    {
        ANYTHING,
        CLOCK_DOMAIN,
        NET,
        CELL,
        CELL_PORT
    } type;
    IdString entity; // Name of clock net; net or cell
    IdString port;   // Name of port on a cell
};

struct TimingConstraint
{
    IdString name;

    enum
    {
        FALSE_PATH,
        MIN_DELAY,
        MAX_DELAY,
        MULTICYCLE,
    } type;

    delay_t value;

    std::unordered_set<TimingConstrObjectId> from;
    std::unordered_set<TimingConstrObjectId> to;
};

// Represents the contents of a non-leaf cell in a design
// with hierarchy

struct HierarchicalPort
{
    IdString name;
    PortType dir;
    std::vector<IdString> nets;
    int offset;
    bool upto;
};

struct HierarchicalCell
{
    IdString name, type, parent, fullpath;
    // Name inside cell instance -> global name
    std::unordered_map<IdString, IdString> leaf_cells, nets;
    // Global name -> name inside cell instance
    std::unordered_map<IdString, IdString> leaf_cells_by_gname, nets_by_gname;
    // Cell port to net
    std::unordered_map<IdString, HierarchicalPort> ports;
    // Name inside cell instance -> global name
    std::unordered_map<IdString, IdString> hier_cells;
};

inline bool operator==(const std::pair<const TimingConstrObjectId, TimingConstraint *> &a,
                       const std::pair<TimingConstrObjectId, TimingConstraint *> &b)
{
    return a.first == b.first && a.second == b.second;
}

struct DeterministicRNG
{
    uint64_t rngstate;

    DeterministicRNG() : rngstate(0x3141592653589793) {}

    uint64_t rng64()
    {
        // xorshift64star
        // https://arxiv.org/abs/1402.6246

        uint64_t retval = rngstate * 0x2545F4914F6CDD1D;

        rngstate ^= rngstate >> 12;
        rngstate ^= rngstate << 25;
        rngstate ^= rngstate >> 27;

        return retval;
    }

    int rng() { return rng64() & 0x3fffffff; }

    int rng(int n)
    {
        assert(n > 0);

        // round up to power of 2
        int m = n - 1;
        m |= (m >> 1);
        m |= (m >> 2);
        m |= (m >> 4);
        m |= (m >> 8);
        m |= (m >> 16);
        m += 1;

        while (1) {
            int x = rng64() & (m - 1);
            if (x < n)
                return x;
        }
    }

    void rngseed(uint64_t seed)
    {
        rngstate = seed ? seed : 0x3141592653589793;
        for (int i = 0; i < 5; i++)
            rng64();
    }

    template <typename T> void shuffle(std::vector<T> &a)
    {
        for (size_t i = 0; i != a.size(); i++) {
            size_t j = i + rng(a.size() - i);
            if (j > i)
                std::swap(a[i], a[j]);
        }
    }

    template <typename T> void sorted_shuffle(std::vector<T> &a)
    {
        std::sort(a.begin(), a.end());
        shuffle(a);
    }
};

struct BaseCtx
{
    // Lock to perform mutating actions on the Context.
    std::mutex mutex;
    boost::thread::id mutex_owner;

    // Lock to be taken by UI when wanting to access context - the yield()
    // method will lock/unlock it when its' released the main mutex to make
    // sure the UI is not starved.
    std::mutex ui_mutex;

    // ID String database.
    mutable std::unordered_map<std::string, int> *idstring_str_to_idx;
    mutable std::vector<const std::string *> *idstring_idx_to_str;

    // Project settings and config switches
    std::unordered_map<IdString, Property> settings;

    // Placed nets and cells.
    std::unordered_map<IdString, std::unique_ptr<NetInfo>> nets;
    std::unordered_map<IdString, std::unique_ptr<CellInfo>> cells;

    // Hierarchical (non-leaf) cells by full path
    std::unordered_map<IdString, HierarchicalCell> hierarchy;
    // This is the root of the above structure
    IdString top_module;

    // Aliases for nets, which may have more than one name due to assignments and hierarchy
    std::unordered_map<IdString, IdString> net_aliases;

    // Top-level ports
    std::unordered_map<IdString, PortInfo> ports;

    // Floorplanning regions
    std::unordered_map<IdString, std::unique_ptr<Region>> region;

    // Context meta data
    std::unordered_map<IdString, Property> attrs;

    BaseCtx()
    {
        idstring_str_to_idx = new std::unordered_map<std::string, int>;
        idstring_idx_to_str = new std::vector<const std::string *>;
        IdString::initialize_add(this, "", 0);
        IdString::initialize_arch(this);

        TimingConstraintObject wildcard;
        wildcard.id.index = 0;
        wildcard.type = TimingConstraintObject::ANYTHING;
        constraintObjects.push_back(wildcard);
    }

    ~BaseCtx()
    {
        delete idstring_str_to_idx;
        delete idstring_idx_to_str;
    }

    // Must be called before performing any mutating changes on the Ctx/Arch.
    void lock(void)
    {
        mutex.lock();
        mutex_owner = boost::this_thread::get_id();
    }

    void unlock(void)
    {
        NPNR_ASSERT(boost::this_thread::get_id() == mutex_owner);
        mutex.unlock();
    }

    // Must be called by the UI before rendering data. This lock will be
    // prioritized when processing code calls yield().
    void lock_ui(void)
    {
        ui_mutex.lock();
        mutex.lock();
    }

    void unlock_ui(void)
    {
        mutex.unlock();
        ui_mutex.unlock();
    }

    // Yield to UI by unlocking the main mutex, flashing the UI mutex and
    // relocking the main mutex. Call this when you're performing a
    // long-standing action while holding a lock to let the UI show
    // visualization updates.
    // Must be called with the main lock taken.
    void yield(void)
    {
        unlock();
        ui_mutex.lock();
        ui_mutex.unlock();
        lock();
    }

    IdString id(const std::string &s) const { return IdString(this, s); }

    IdString id(const char *s) const { return IdString(this, s); }

    Context *getCtx() { return reinterpret_cast<Context *>(this); }

    const Context *getCtx() const { return reinterpret_cast<const Context *>(this); }

    const char *nameOf(IdString name) const { return name.c_str(this); }

    template <typename T> const char *nameOf(const T *obj) const
    {
        if (obj == nullptr)
            return "";
        return obj->name.c_str(this);
    }

    const char *nameOfBel(BelId bel) const;
    const char *nameOfWire(WireId wire) const;
    const char *nameOfPip(PipId pip) const;
    const char *nameOfGroup(GroupId group) const;

    // --------------------------------------------------------------

    bool allUiReload = true;
    bool frameUiReload = false;
    std::unordered_set<BelId> belUiReload;
    std::unordered_set<WireId> wireUiReload;
    std::unordered_set<PipId> pipUiReload;
    std::unordered_set<GroupId> groupUiReload;

    void refreshUi() { allUiReload = true; }

    void refreshUiFrame() { frameUiReload = true; }

    void refreshUiBel(BelId bel) { belUiReload.insert(bel); }

    void refreshUiWire(WireId wire) { wireUiReload.insert(wire); }

    void refreshUiPip(PipId pip) { pipUiReload.insert(pip); }

    void refreshUiGroup(GroupId group) { groupUiReload.insert(group); }

    // --------------------------------------------------------------

    // Timing Constraint API

    // constraint name -> constraint
    std::unordered_map<IdString, std::unique_ptr<TimingConstraint>> constraints;
    // object ID -> object
    std::vector<TimingConstraintObject> constraintObjects;
    // object ID -> constraint
    std::unordered_multimap<TimingConstrObjectId, TimingConstraint *> constrsFrom;
    std::unordered_multimap<TimingConstrObjectId, TimingConstraint *> constrsTo;

    TimingConstrObjectId timingWildcardObject();
    TimingConstrObjectId timingClockDomainObject(NetInfo *clockDomain);
    TimingConstrObjectId timingNetObject(NetInfo *net);
    TimingConstrObjectId timingCellObject(CellInfo *cell);
    TimingConstrObjectId timingPortObject(CellInfo *cell, IdString port);

    NetInfo *getNetByAlias(IdString alias) const
    {
        return nets.count(alias) ? nets.at(alias).get() : nets.at(net_aliases.at(alias)).get();
    }

    void addConstraint(std::unique_ptr<TimingConstraint> constr);
    void removeConstraint(IdString constrName);

    // Intended to simplify Python API
    void addClock(IdString net, float freq);
    void createRectangularRegion(IdString name, int x0, int y0, int x1, int y1);
    void addBelToRegion(IdString name, BelId bel);
    void constrainCellToRegion(IdString cell, IdString region_name);

    // Helper functions for Python bindings
    NetInfo *createNet(IdString name);
    void connectPort(IdString net, IdString cell, IdString port);
    void disconnectPort(IdString cell, IdString port);
    void ripupNet(IdString name);
    void lockNetRouting(IdString name);

    CellInfo *createCell(IdString name, IdString type);
    void copyBelPorts(IdString cell, BelId bel);

    // Workaround for lack of wrappable constructors
    DecalXY constructDecalXY(DecalId decal, float x, float y);

    void archInfoToAttributes();
    void attributesToArchInfo();
};

NEXTPNR_NAMESPACE_END

#include "arch.h"

NEXTPNR_NAMESPACE_BEGIN

struct Context : Arch, DeterministicRNG
{
    bool verbose = false;
    bool debug = false;
    bool force = false;

    Context(ArchArgs args) : Arch(args) {}

    // --------------------------------------------------------------

    WireId getNetinfoSourceWire(const NetInfo *net_info) const;
    WireId getNetinfoSinkWire(const NetInfo *net_info, const PortRef &sink) const;
    delay_t getNetinfoRouteDelay(const NetInfo *net_info, const PortRef &sink) const;

    // provided by router1.cc
    bool checkRoutedDesign() const;
    bool getActualRouteDelay(WireId src_wire, WireId dst_wire, delay_t *delay = nullptr,
                             std::unordered_map<WireId, PipId> *route = nullptr, bool useEstimate = true);

    // --------------------------------------------------------------
    // call after changing hierpath or adding/removing nets and cells
    void fixupHierarchy();

    // --------------------------------------------------------------

    // provided by sdf.cc
    void writeSDF(std::ostream &out, bool cvc_mode = false) const;

    // --------------------------------------------------------------

    // provided by svg.cc
    void writeSVG(const std::string &filename, const std::string &flags = "") const;

    // --------------------------------------------------------------

    uint32_t checksum() const;

    void check() const;
    void archcheck() const;

    template <typename T> T setting(const char *name, T defaultValue)
    {
        IdString new_id = id(name);
        auto found = settings.find(new_id);
        if (found != settings.end())
            return boost::lexical_cast<T>(found->second.is_string ? found->second.as_string()
                                                                  : std::to_string(found->second.as_int64()));
        else
            settings[id(name)] = std::to_string(defaultValue);

        return defaultValue;
    }

    template <typename T> T setting(const char *name) const
    {
        IdString new_id = id(name);
        auto found = settings.find(new_id);
        if (found != settings.end())
            return boost::lexical_cast<T>(found->second.is_string ? found->second.as_string()
                                                                  : std::to_string(found->second.as_int64()));
        else
            throw std::runtime_error("settings does not exists");
    }
};

NEXTPNR_NAMESPACE_END

#endif
ON_CALL(*this, DoThat(_)) .WillByDefault(Invoke(&real_, &Foo::DoThat)); ... } MOCK_METHOD0(DoThis, ...); MOCK_METHOD1(DoThat, ...); ... private: Foo real_; }; ... MockFoo mock; EXPECT_CALL(mock, DoThis()) .Times(3); EXPECT_CALL(mock, DoThat("Hi")) .Times(AtLeast(1)); ... use mock in test ... ``` With this, Google Mock will verify that your code made the right calls (with the right arguments, in the right order, called the right number of times, etc), and a real object will answer the calls (so the behavior will be the same as in production). This gives you the best of both worlds. ## Delegating Calls to a Parent Class ## Ideally, you should code to interfaces, whose methods are all pure virtual. In reality, sometimes you do need to mock a virtual method that is not pure (i.e, it already has an implementation). For example: ``` class Foo { public: virtual ~Foo(); virtual void Pure(int n) = 0; virtual int Concrete(const char* str) { ... } }; class MockFoo : public Foo { public: // Mocking a pure method. MOCK_METHOD1(Pure, void(int n)); // Mocking a concrete method. Foo::Concrete() is shadowed. MOCK_METHOD1(Concrete, int(const char* str)); }; ``` Sometimes you may want to call `Foo::Concrete()` instead of `MockFoo::Concrete()`. Perhaps you want to do it as part of a stub action, or perhaps your test doesn't need to mock `Concrete()` at all (but it would be oh-so painful to have to define a new mock class whenever you don't need to mock one of its methods). The trick is to leave a back door in your mock class for accessing the real methods in the base class: ``` class MockFoo : public Foo { public: // Mocking a pure method. MOCK_METHOD1(Pure, void(int n)); // Mocking a concrete method. Foo::Concrete() is shadowed. MOCK_METHOD1(Concrete, int(const char* str)); // Use this to call Concrete() defined in Foo. int FooConcrete(const char* str) { return Foo::Concrete(str); } }; ``` Now, you can call `Foo::Concrete()` inside an action by: ``` using ::testing::_; using ::testing::Invoke; ... EXPECT_CALL(foo, Concrete(_)) .WillOnce(Invoke(&foo, &MockFoo::FooConcrete)); ``` or tell the mock object that you don't want to mock `Concrete()`: ``` using ::testing::Invoke; ... ON_CALL(foo, Concrete(_)) .WillByDefault(Invoke(&foo, &MockFoo::FooConcrete)); ``` (Why don't we just write `Invoke(&foo, &Foo::Concrete)`? If you do that, `MockFoo::Concrete()` will be called (and cause an infinite recursion) since `Foo::Concrete()` is virtual. That's just how C++ works.) # Using Matchers # ## Matching Argument Values Exactly ## You can specify exactly which arguments a mock method is expecting: ``` using ::testing::Return; ... EXPECT_CALL(foo, DoThis(5)) .WillOnce(Return('a')); EXPECT_CALL(foo, DoThat("Hello", bar)); ``` ## Using Simple Matchers ## You can use matchers to match arguments that have a certain property: ``` using ::testing::Ge; using ::testing::NotNull; using ::testing::Return; ... EXPECT_CALL(foo, DoThis(Ge(5))) // The argument must be >= 5. .WillOnce(Return('a')); EXPECT_CALL(foo, DoThat("Hello", NotNull())); // The second argument must not be NULL. ``` A frequently used matcher is `_`, which matches anything: ``` using ::testing::_; using ::testing::NotNull; ... EXPECT_CALL(foo, DoThat(_, NotNull())); ``` ## Combining Matchers ## You can build complex matchers from existing ones using `AllOf()`, `AnyOf()`, and `Not()`: ``` using ::testing::AllOf; using ::testing::Gt; using ::testing::HasSubstr; using ::testing::Ne; using ::testing::Not; ... // The argument must be > 5 and != 10. EXPECT_CALL(foo, DoThis(AllOf(Gt(5), Ne(10)))); // The first argument must not contain sub-string "blah". EXPECT_CALL(foo, DoThat(Not(HasSubstr("blah")), NULL)); ``` ## Casting Matchers ## Google Mock matchers are statically typed, meaning that the compiler can catch your mistake if you use a matcher of the wrong type (for example, if you use `Eq(5)` to match a `string` argument). Good for you! Sometimes, however, you know what you're doing and want the compiler to give you some slack. One example is that you have a matcher for `long` and the argument you want to match is `int`. While the two types aren't exactly the same, there is nothing really wrong with using a `Matcher<long>` to match an `int` - after all, we can first convert the `int` argument to a `long` before giving it to the matcher. To support this need, Google Mock gives you the `SafeMatcherCast<T>(m)` function. It casts a matcher `m` to type `Matcher<T>`. To ensure safety, Google Mock checks that (let `U` be the type `m` accepts): 1. Type `T` can be implicitly cast to type `U`; 1. When both `T` and `U` are built-in arithmetic types (`bool`, integers, and floating-point numbers), the conversion from `T` to `U` is not lossy (in other words, any value representable by `T` can also be represented by `U`); and 1. When `U` is a reference, `T` must also be a reference (as the underlying matcher may be interested in the address of the `U` value). The code won't compile if any of these conditions isn't met. Here's one example: ``` using ::testing::SafeMatcherCast; // A base class and a child class. class Base { ... }; class Derived : public Base { ... }; class MockFoo : public Foo { public: MOCK_METHOD1(DoThis, void(Derived* derived)); }; ... MockFoo foo; // m is a Matcher<Base*> we got from somewhere. EXPECT_CALL(foo, DoThis(SafeMatcherCast<Derived*>(m))); ``` If you find `SafeMatcherCast<T>(m)` too limiting, you can use a similar function `MatcherCast<T>(m)`. The difference is that `MatcherCast` works as long as you can `static_cast` type `T` to type `U`. `MatcherCast` essentially lets you bypass C++'s type system (`static_cast` isn't always safe as it could throw away information, for example), so be careful not to misuse/abuse it. ## Selecting Between Overloaded Functions ## If you expect an overloaded function to be called, the compiler may need some help on which overloaded version it is. To disambiguate functions overloaded on the const-ness of this object, use the `Const()` argument wrapper. ``` using ::testing::ReturnRef; class MockFoo : public Foo { ... MOCK_METHOD0(GetBar, Bar&()); MOCK_CONST_METHOD0(GetBar, const Bar&()); }; ... MockFoo foo; Bar bar1, bar2; EXPECT_CALL(foo, GetBar()) // The non-const GetBar(). .WillOnce(ReturnRef(bar1)); EXPECT_CALL(Const(foo), GetBar()) // The const GetBar(). .WillOnce(ReturnRef(bar2)); ``` (`Const()` is defined by Google Mock and returns a `const` reference to its argument.) To disambiguate overloaded functions with the same number of arguments but different argument types, you may need to specify the exact type of a matcher, either by wrapping your matcher in `Matcher<type>()`, or using a matcher whose type is fixed (`TypedEq<type>`, `An<type>()`, etc): ``` using ::testing::An; using ::testing::Lt; using ::testing::Matcher; using ::testing::TypedEq; class MockPrinter : public Printer { public: MOCK_METHOD1(Print, void(int n)); MOCK_METHOD1(Print, void(char c)); }; TEST(PrinterTest, Print) { MockPrinter printer; EXPECT_CALL(printer, Print(An<int>())); // void Print(int); EXPECT_CALL(printer, Print(Matcher<int>(Lt(5)))); // void Print(int); EXPECT_CALL(printer, Print(TypedEq<char>('a'))); // void Print(char); printer.Print(3); printer.Print(6); printer.Print('a'); } ``` ## Performing Different Actions Based on the Arguments ## When a mock method is called, the _last_ matching expectation that's still active will be selected (think "newer overrides older"). So, you can make a method do different things depending on its argument values like this: ``` using ::testing::_; using ::testing::Lt; using ::testing::Return; ... // The default case. EXPECT_CALL(foo, DoThis(_)) .WillRepeatedly(Return('b')); // The more specific case. EXPECT_CALL(foo, DoThis(Lt(5))) .WillRepeatedly(Return('a')); ``` Now, if `foo.DoThis()` is called with a value less than 5, `'a'` will be returned; otherwise `'b'` will be returned. ## Matching Multiple Arguments as a Whole ## Sometimes it's not enough to match the arguments individually. For example, we may want to say that the first argument must be less than the second argument. The `With()` clause allows us to match all arguments of a mock function as a whole. For example, ``` using ::testing::_; using ::testing::Lt; using ::testing::Ne; ... EXPECT_CALL(foo, InRange(Ne(0), _)) .With(Lt()); ``` says that the first argument of `InRange()` must not be 0, and must be less than the second argument. The expression inside `With()` must be a matcher of type `Matcher<tr1::tuple<A1, ..., An> >`, where `A1`, ..., `An` are the types of the function arguments. You can also write `AllArgs(m)` instead of `m` inside `.With()`. The two forms are equivalent, but `.With(AllArgs(Lt()))` is more readable than `.With(Lt())`. You can use `Args<k1, ..., kn>(m)` to match the `n` selected arguments (as a tuple) against `m`. For example, ``` using ::testing::_; using ::testing::AllOf; using ::testing::Args; using ::testing::Lt; ... EXPECT_CALL(foo, Blah(_, _, _)) .With(AllOf(Args<0, 1>(Lt()), Args<1, 2>(Lt()))); ``` says that `Blah()` will be called with arguments `x`, `y`, and `z` where `x < y < z`. As a convenience and example, Google Mock provides some matchers for 2-tuples, including the `Lt()` matcher above. See the [CheatSheet](V1_6_CheatSheet.md) for the complete list. Note that if you want to pass the arguments to a predicate of your own (e.g. `.With(Args<0, 1>(Truly(&MyPredicate)))`), that predicate MUST be written to take a `tr1::tuple` as its argument; Google Mock will pass the `n` selected arguments as _one_ single tuple to the predicate. ## Using Matchers as Predicates ## Have you noticed that a matcher is just a fancy predicate that also knows how to describe itself? Many existing algorithms take predicates as arguments (e.g. those defined in STL's `<algorithm>` header), and it would be a shame if Google Mock matchers are not allowed to participate. Luckily, you can use a matcher where a unary predicate functor is expected by wrapping it inside the `Matches()` function. For example, ``` #include <algorithm> #include <vector> std::vector<int> v; ... // How many elements in v are >= 10? const int count = count_if(v.begin(), v.end(), Matches(Ge(10))); ``` Since you can build complex matchers from simpler ones easily using Google Mock, this gives you a way to conveniently construct composite predicates (doing the same using STL's `<functional>` header is just painful). For example, here's a predicate that's satisfied by any number that is >= 0, <= 100, and != 50: ``` Matches(AllOf(Ge(0), Le(100), Ne(50))) ``` ## Using Matchers in Google Test Assertions ## Since matchers are basically predicates that also know how to describe themselves, there is a way to take advantage of them in [Google Test](http://code.google.com/p/googletest/) assertions. It's called `ASSERT_THAT` and `EXPECT_THAT`: ``` ASSERT_THAT(value, matcher); // Asserts that value matches matcher. EXPECT_THAT(value, matcher); // The non-fatal version. ``` For example, in a Google Test test you can write: ``` #include "gmock/gmock.h" using ::testing::AllOf; using ::testing::Ge; using ::testing::Le; using ::testing::MatchesRegex; using ::testing::StartsWith; ... EXPECT_THAT(Foo(), StartsWith("Hello")); EXPECT_THAT(Bar(), MatchesRegex("Line \\d+")); ASSERT_THAT(Baz(), AllOf(Ge(5), Le(10))); ``` which (as you can probably guess) executes `Foo()`, `Bar()`, and `Baz()`, and verifies that: * `Foo()` returns a string that starts with `"Hello"`. * `Bar()` returns a string that matches regular expression `"Line \\d+"`. * `Baz()` returns a number in the range [5, 10]. The nice thing about these macros is that _they read like English_. They generate informative messages too. For example, if the first `EXPECT_THAT()` above fails, the message will be something like: ``` Value of: Foo() Actual: "Hi, world!" Expected: starts with "Hello" ``` **Credit:** The idea of `(ASSERT|EXPECT)_THAT` was stolen from the [Hamcrest](http://code.google.com/p/hamcrest/) project, which adds `assertThat()` to JUnit. ## Using Predicates as Matchers ## Google Mock provides a built-in set of matchers. In case you find them lacking, you can use an arbitray unary predicate function or functor as a matcher - as long as the predicate accepts a value of the type you want. You do this by wrapping the predicate inside the `Truly()` function, for example: ``` using ::testing::Truly; int IsEven(int n) { return (n % 2) == 0 ? 1 : 0; } ... // Bar() must be called with an even number. EXPECT_CALL(foo, Bar(Truly(IsEven))); ``` Note that the predicate function / functor doesn't have to return `bool`. It works as long as the return value can be used as the condition in statement `if (condition) ...`. ## Matching Arguments that Are Not Copyable ## When you do an `EXPECT_CALL(mock_obj, Foo(bar))`, Google Mock saves away a copy of `bar`. When `Foo()` is called later, Google Mock compares the argument to `Foo()` with the saved copy of `bar`. This way, you don't need to worry about `bar` being modified or destroyed after the `EXPECT_CALL()` is executed. The same is true when you use matchers like `Eq(bar)`, `Le(bar)`, and so on. But what if `bar` cannot be copied (i.e. has no copy constructor)? You could define your own matcher function and use it with `Truly()`, as the previous couple of recipes have shown. Or, you may be able to get away from it if you can guarantee that `bar` won't be changed after the `EXPECT_CALL()` is executed. Just tell Google Mock that it should save a reference to `bar`, instead of a copy of it. Here's how: ``` using ::testing::Eq; using ::testing::ByRef; using ::testing::Lt; ... // Expects that Foo()'s argument == bar. EXPECT_CALL(mock_obj, Foo(Eq(ByRef(bar)))); // Expects that Foo()'s argument < bar. EXPECT_CALL(mock_obj, Foo(Lt(ByRef(bar)))); ``` Remember: if you do this, don't change `bar` after the `EXPECT_CALL()`, or the result is undefined. ## Validating a Member of an Object ## Often a mock function takes a reference to object as an argument. When matching the argument, you may not want to compare the entire object against a fixed object, as that may be over-specification. Instead, you may need to validate a certain member variable or the result of a certain getter method of the object. You can do this with `Field()` and `Property()`. More specifically, ``` Field(&Foo::bar, m) ``` is a matcher that matches a `Foo` object whose `bar` member variable satisfies matcher `m`. ``` Property(&Foo::baz, m) ``` is a matcher that matches a `Foo` object whose `baz()` method returns a value that satisfies matcher `m`. For example: > | `Field(&Foo::number, Ge(3))` | Matches `x` where `x.number >= 3`. | |:-----------------------------|:-----------------------------------| > | `Property(&Foo::name, StartsWith("John "))` | Matches `x` where `x.name()` starts with `"John "`. | Note that in `Property(&Foo::baz, ...)`, method `baz()` must take no argument and be declared as `const`. BTW, `Field()` and `Property()` can also match plain pointers to objects. For instance, ``` Field(&Foo::number, Ge(3)) ``` matches a plain pointer `p` where `p->number >= 3`. If `p` is `NULL`, the match will always fail regardless of the inner matcher. What if you want to validate more than one members at the same time? Remember that there is `AllOf()`. ## Validating the Value Pointed to by a Pointer Argument ## C++ functions often take pointers as arguments. You can use matchers like `NULL`, `NotNull()`, and other comparison matchers to match a pointer, but what if you want to make sure the value _pointed to_ by the pointer, instead of the pointer itself, has a certain property? Well, you can use the `Pointee(m)` matcher. `Pointee(m)` matches a pointer iff `m` matches the value the pointer points to. For example: ``` using ::testing::Ge; using ::testing::Pointee; ... EXPECT_CALL(foo, Bar(Pointee(Ge(3)))); ``` expects `foo.Bar()` to be called with a pointer that points to a value greater than or equal to 3. One nice thing about `Pointee()` is that it treats a `NULL` pointer as a match failure, so you can write `Pointee(m)` instead of ``` AllOf(NotNull(), Pointee(m)) ``` without worrying that a `NULL` pointer will crash your test. Also, did we tell you that `Pointee()` works with both raw pointers **and** smart pointers (`linked_ptr`, `shared_ptr`, `scoped_ptr`, and etc)? What if you have a pointer to pointer? You guessed it - you can use nested `Pointee()` to probe deeper inside the value. For example, `Pointee(Pointee(Lt(3)))` matches a pointer that points to a pointer that points to a number less than 3 (what a mouthful...). ## Testing a Certain Property of an Object ## Sometimes you want to specify that an object argument has a certain property, but there is no existing matcher that does this. If you want good error messages, you should define a matcher. If you want to do it quick and dirty, you could get away with writing an ordinary function. Let's say you have a mock function that takes an object of type `Foo`, which has an `int bar()` method and an `int baz()` method, and you want to constrain that the argument's `bar()` value plus its `baz()` value is a given number. Here's how you can define a matcher to do it: ``` using ::testing::MatcherInterface; using ::testing::MatchResultListener; class BarPlusBazEqMatcher : public MatcherInterface<const Foo&> { public: explicit BarPlusBazEqMatcher(int expected_sum) : expected_sum_(expected_sum) {} virtual bool MatchAndExplain(const Foo& foo, MatchResultListener* listener) const { return (foo.bar() + foo.baz()) == expected_sum_; } virtual void DescribeTo(::std::ostream* os) const { *os << "bar() + baz() equals " << expected_sum_; } virtual void DescribeNegationTo(::std::ostream* os) const { *os << "bar() + baz() does not equal " << expected_sum_; } private: const int expected_sum_; }; inline Matcher<const Foo&> BarPlusBazEq(int expected_sum) { return MakeMatcher(new BarPlusBazEqMatcher(expected_sum)); } ... EXPECT_CALL(..., DoThis(BarPlusBazEq(5)))...; ``` ## Matching Containers ## Sometimes an STL container (e.g. list, vector, map, ...) is passed to a mock function and you may want to validate it. Since most STL containers support the `==` operator, you can write `Eq(expected_container)` or simply `expected_container` to match a container exactly. Sometimes, though, you may want to be more flexible (for example, the first element must be an exact match, but the second element can be any positive number, and so on). Also, containers used in tests often have a small number of elements, and having to define the expected container out-of-line is a bit of a hassle. You can use the `ElementsAre()` matcher in such cases: ``` using ::testing::_; using ::testing::ElementsAre; using ::testing::Gt; ... MOCK_METHOD1(Foo, void(const vector<int>& numbers)); ... EXPECT_CALL(mock, Foo(ElementsAre(1, Gt(0), _, 5))); ``` The above matcher says that the container must have 4 elements, which must be 1, greater than 0, anything, and 5 respectively. `ElementsAre()` is overloaded to take 0 to 10 arguments. If more are needed, you can place them in a C-style array and use `ElementsAreArray()` instead: ``` using ::testing::ElementsAreArray; ... // ElementsAreArray accepts an array of element values. const int expected_vector1[] = { 1, 5, 2, 4, ... }; EXPECT_CALL(mock, Foo(ElementsAreArray(expected_vector1))); // Or, an array of element matchers. Matcher<int> expected_vector2 = { 1, Gt(2), _, 3, ... }; EXPECT_CALL(mock, Foo(ElementsAreArray(expected_vector2))); ``` In case the array needs to be dynamically created (and therefore the array size cannot be inferred by the compiler), you can give `ElementsAreArray()` an additional argument to specify the array size: ``` using ::testing::ElementsAreArray; ... int* const expected_vector3 = new int[count]; ... fill expected_vector3 with values ... EXPECT_CALL(mock, Foo(ElementsAreArray(expected_vector3, count))); ``` **Tips:** * `ElementAre*()` works with _any_ container that implements the STL iterator concept (i.e. it has a `const_iterator` type and supports `begin()/end()`) and supports `size()`, not just the ones defined in STL. It will even work with container types yet to be written - as long as they follows the above pattern. * You can use nested `ElementAre*()` to match nested (multi-dimensional) containers. * If the container is passed by pointer instead of by reference, just write `Pointee(ElementsAre*(...))`. * The order of elements _matters_ for `ElementsAre*()`. Therefore don't use it with containers whose element order is undefined (e.g. `hash_map`). ## Sharing Matchers ## Under the hood, a Google Mock matcher object consists of a pointer to a ref-counted implementation object. Copying matchers is allowed and very efficient, as only the pointer is copied. When the last matcher that references the implementation object dies, the implementation object will be deleted. Therefore, if you have some complex matcher that you want to use again and again, there is no need to build it everytime. Just assign it to a matcher variable and use that variable repeatedly! For example, ``` Matcher<int> in_range = AllOf(Gt(5), Le(10)); ... use in_range as a matcher in multiple EXPECT_CALLs ... ``` # Setting Expectations # ## Ignoring Uninteresting Calls ## If you are not interested in how a mock method is called, just don't say anything about it. In this case, if the method is ever called, Google Mock will perform its default action to allow the test program to continue. If you are not happy with the default action taken by Google Mock, you can override it using `DefaultValue<T>::Set()` (described later in this document) or `ON_CALL()`. Please note that once you expressed interest in a particular mock method (via `EXPECT_CALL()`), all invocations to it must match some expectation. If this function is called but the arguments don't match any `EXPECT_CALL()` statement, it will be an error. ## Disallowing Unexpected Calls ## If a mock method shouldn't be called at all, explicitly say so: ``` using ::testing::_; ... EXPECT_CALL(foo, Bar(_)) .Times(0); ``` If some calls to the method are allowed, but the rest are not, just list all the expected calls: ``` using ::testing::AnyNumber; using ::testing::Gt; ... EXPECT_CALL(foo, Bar(5)); EXPECT_CALL(foo, Bar(Gt(10))) .Times(AnyNumber()); ``` A call to `foo.Bar()` that doesn't match any of the `EXPECT_CALL()` statements will be an error. ## Expecting Ordered Calls ## Although an `EXPECT_CALL()` statement defined earlier takes precedence when Google Mock tries to match a function call with an expectation, by default calls don't have to happen in the order `EXPECT_CALL()` statements are written. For example, if the arguments match the matchers in the third `EXPECT_CALL()`, but not those in the first two, then the third expectation will be used. If you would rather have all calls occur in the order of the expectations, put the `EXPECT_CALL()` statements in a block where you define a variable of type `InSequence`: ``` using ::testing::_; using ::testing::InSequence; { InSequence s; EXPECT_CALL(foo, DoThis(5)); EXPECT_CALL(bar, DoThat(_)) .Times(2); EXPECT_CALL(foo, DoThis(6)); } ``` In this example, we expect a call to `foo.DoThis(5)`, followed by two calls to `bar.DoThat()` where the argument can be anything, which are in turn followed by a call to `foo.DoThis(6)`. If a call occurred out-of-order, Google Mock will report an error. ## Expecting Partially Ordered Calls ## Sometimes requiring everything to occur in a predetermined order can lead to brittle tests. For example, we may care about `A` occurring before both `B` and `C`, but aren't interested in the relative order of `B` and `C`. In this case, the test should reflect our real intent, instead of being overly constraining. Google Mock allows you to impose an arbitrary DAG (directed acyclic graph) on the calls. One way to express the DAG is to use the [After](http://code.google.com/p/googlemock/wiki/V1_6_CheatSheet#The_After_Clause) clause of `EXPECT_CALL`. Another way is via the `InSequence()` clause (not the same as the `InSequence` class), which we borrowed from jMock 2. It's less flexible than `After()`, but more convenient when you have long chains of sequential calls, as it doesn't require you to come up with different names for the expectations in the chains. Here's how it works: If we view `EXPECT_CALL()` statements as nodes in a graph, and add an edge from node A to node B wherever A must occur before B, we can get a DAG. We use the term "sequence" to mean a directed path in this DAG. Now, if we decompose the DAG into sequences, we just need to know which sequences each `EXPECT_CALL()` belongs to in order to be able to reconstruct the orginal DAG. So, to specify the partial order on the expectations we need to do two things: first to define some `Sequence` objects, and then for each `EXPECT_CALL()` say which `Sequence` objects it is part of. Expectations in the same sequence must occur in the order they are written. For example, ``` using ::testing::Sequence; Sequence s1, s2; EXPECT_CALL(foo, A()) .InSequence(s1, s2); EXPECT_CALL(bar, B()) .InSequence(s1); EXPECT_CALL(bar, C()) .InSequence(s2); EXPECT_CALL(foo, D()) .InSequence(s2); ``` specifies the following DAG (where `s1` is `A -> B`, and `s2` is `A -> C -> D`): ``` +---> B | A ---| | +---> C ---> D ``` This means that A must occur before B and C, and C must occur before D. There's no restriction about the order other than these. ## Controlling When an Expectation Retires ## When a mock method is called, Google Mock only consider expectations that are still active. An expectation is active when created, and becomes inactive (aka _retires_) when a call that has to occur later has occurred. For example, in ``` using ::testing::_; using ::testing::Sequence; Sequence s1, s2; EXPECT_CALL(log, Log(WARNING, _, "File too large.")) // #1 .Times(AnyNumber()) .InSequence(s1, s2); EXPECT_CALL(log, Log(WARNING, _, "Data set is empty.")) // #2 .InSequence(s1); EXPECT_CALL(log, Log(WARNING, _, "User not found.")) // #3 .InSequence(s2); ``` as soon as either #2 or #3 is matched, #1 will retire. If a warning `"File too large."` is logged after this, it will be an error. Note that an expectation doesn't retire automatically when it's saturated. For example, ``` using ::testing::_; ... EXPECT_CALL(log, Log(WARNING, _, _)); // #1 EXPECT_CALL(log, Log(WARNING, _, "File too large.")); // #2 ``` says that there will be exactly one warning with the message `"File too large."`. If the second warning contains this message too, #2 will match again and result in an upper-bound-violated error. If this is not what you want, you can ask an expectation to retire as soon as it becomes saturated: ``` using ::testing::_; ... EXPECT_CALL(log, Log(WARNING, _, _)); // #1 EXPECT_CALL(log, Log(WARNING, _, "File too large.")) // #2 .RetiresOnSaturation(); ``` Here #2 can be used only once, so if you have two warnings with the message `"File too large."`, the first will match #2 and the second will match #1 - there will be no error. # Using Actions # ## Returning References from Mock Methods ## If a mock function's return type is a reference, you need to use `ReturnRef()` instead of `Return()` to return a result: ``` using ::testing::ReturnRef; class MockFoo : public Foo { public: MOCK_METHOD0(GetBar, Bar&()); }; ... MockFoo foo; Bar bar; EXPECT_CALL(foo, GetBar()) .WillOnce(ReturnRef(bar)); ``` ## Returning Live Values from Mock Methods ## The `Return(x)` action saves a copy of `x` when the action is _created_, and always returns the same value whenever it's executed. Sometimes you may want to instead return the _live_ value of `x` (i.e. its value at the time when the action is _executed_.). If the mock function's return type is a reference, you can do it using `ReturnRef(x)`, as shown in the previous recipe ("Returning References from Mock Methods"). However, Google Mock doesn't let you use `ReturnRef()` in a mock function whose return type is not a reference, as doing that usually indicates a user error. So, what shall you do? You may be tempted to try `ByRef()`: ``` using testing::ByRef; using testing::Return; class MockFoo : public Foo { public: MOCK_METHOD0(GetValue, int()); }; ... int x = 0; MockFoo foo; EXPECT_CALL(foo, GetValue()) .WillRepeatedly(Return(ByRef(x))); x = 42; EXPECT_EQ(42, foo.GetValue()); ``` Unfortunately, it doesn't work here. The above code will fail with error: ``` Value of: foo.GetValue() Actual: 0 Expected: 42 ``` The reason is that `Return(value)` converts `value` to the actual return type of the mock function at the time when the action is _created_, not when it is _executed_. (This behavior was chosen for the action to be safe when `value` is a proxy object that references some temporary objects.) As a result, `ByRef(x)` is converted to an `int` value (instead of a `const int&`) when the expectation is set, and `Return(ByRef(x))` will always return 0. `ReturnPointee(pointer)` was provided to solve this problem specifically. It returns the value pointed to by `pointer` at the time the action is _executed_: ``` using testing::ReturnPointee; ... int x = 0; MockFoo foo; EXPECT_CALL(foo, GetValue()) .WillRepeatedly(ReturnPointee(&x)); // Note the & here. x = 42; EXPECT_EQ(42, foo.GetValue()); // This will succeed now. ``` ## Combining Actions ## Want to do more than one thing when a function is called? That's fine. `DoAll()` allow you to do sequence of actions every time. Only the return value of the last action in the sequence will be used. ``` using ::testing::DoAll; class MockFoo : public Foo { public: MOCK_METHOD1(Bar, bool(int n)); }; ... EXPECT_CALL(foo, Bar(_)) .WillOnce(DoAll(action_1, action_2, ... action_n)); ``` ## Mocking Side Effects ## Sometimes a method exhibits its effect not via returning a value but via side effects. For example, it may change some global state or modify an output argument. To mock side effects, in general you can define your own action by implementing `::testing::ActionInterface`. If all you need to do is to change an output argument, the built-in `SetArgPointee()` action is convenient: ``` using ::testing::SetArgPointee; class MockMutator : public Mutator { public: MOCK_METHOD2(Mutate, void(bool mutate, int* value)); ... }; ... MockMutator mutator; EXPECT_CALL(mutator, Mutate(true, _)) .WillOnce(SetArgPointee<1>(5)); ``` In this example, when `mutator.Mutate()` is called, we will assign 5 to the `int` variable pointed to by argument #1 (0-based). `SetArgPointee()` conveniently makes an internal copy of the value you pass to it, removing the need to keep the value in scope and alive. The implication however is that the value must have a copy constructor and assignment operator. If the mock method also needs to return a value as well, you can chain `SetArgPointee()` with `Return()` using `DoAll()`: ``` using ::testing::_; using ::testing::Return; using ::testing::SetArgPointee; class MockMutator : public Mutator { public: ... MOCK_METHOD1(MutateInt, bool(int* value)); }; ... MockMutator mutator; EXPECT_CALL(mutator, MutateInt(_)) .WillOnce(DoAll(SetArgPointee<0>(5), Return(true))); ``` If the output argument is an array, use the `SetArrayArgument<N>(first, last)` action instead. It copies the elements in source range `[first, last)` to the array pointed to by the `N`-th (0-based) argument: ``` using ::testing::NotNull; using ::testing::SetArrayArgument; class MockArrayMutator : public ArrayMutator { public: MOCK_METHOD2(Mutate, void(int* values, int num_values)); ... }; ... MockArrayMutator mutator; int values[5] = { 1, 2, 3, 4, 5 }; EXPECT_CALL(mutator, Mutate(NotNull(), 5)) .WillOnce(SetArrayArgument<0>(values, values + 5)); ``` This also works when the argument is an output iterator: ``` using ::testing::_; using ::testing::SeArrayArgument; class MockRolodex : public Rolodex { public: MOCK_METHOD1(GetNames, void(std::back_insert_iterator<vector<string> >)); ... }; ... MockRolodex rolodex; vector<string> names; names.push_back("George"); names.push_back("John"); names.push_back("Thomas"); EXPECT_CALL(rolodex, GetNames(_)) .WillOnce(SetArrayArgument<0>(names.begin(), names.end())); ``` ## Changing a Mock Object's Behavior Based on the State ## If you expect a call to change the behavior of a mock object, you can use `::testing::InSequence` to specify different behaviors before and after the call: ``` using ::testing::InSequence; using ::testing::Return; ... { InSequence seq; EXPECT_CALL(my_mock, IsDirty()) .WillRepeatedly(Return(true)); EXPECT_CALL(my_mock, Flush()); EXPECT_CALL(my_mock, IsDirty()) .WillRepeatedly(Return(false)); } my_mock.FlushIfDirty(); ``` This makes `my_mock.IsDirty()` return `true` before `my_mock.Flush()` is called and return `false` afterwards. If the behavior change is more complex, you can store the effects in a variable and make a mock method get its return value from that variable: ``` using ::testing::_; using ::testing::SaveArg; using ::testing::Return; ACTION_P(ReturnPointee, p) { return *p; } ... int previous_value = 0; EXPECT_CALL(my_mock, GetPrevValue()) .WillRepeatedly(ReturnPointee(&previous_value)); EXPECT_CALL(my_mock, UpdateValue(_)) .WillRepeatedly(SaveArg<0>(&previous_value)); my_mock.DoSomethingToUpdateValue(); ``` Here `my_mock.GetPrevValue()` will always return the argument of the last `UpdateValue()` call. ## Setting the Default Value for a Return Type ## If a mock method's return type is a built-in C++ type or pointer, by default it will return 0 when invoked. You only need to specify an action if this default value doesn't work for you. Sometimes, you may want to change this default value, or you may want to specify a default value for types Google Mock doesn't know about. You can do this using the `::testing::DefaultValue` class template: ``` class MockFoo : public Foo { public: MOCK_METHOD0(CalculateBar, Bar()); }; ... Bar default_bar; // Sets the default return value for type Bar. DefaultValue<Bar>::Set(default_bar); MockFoo foo; // We don't need to specify an action here, as the default // return value works for us. EXPECT_CALL(foo, CalculateBar()); foo.CalculateBar(); // This should return default_bar. // Unsets the default return value. DefaultValue<Bar>::Clear(); ``` Please note that changing the default value for a type can make you tests hard to understand. We recommend you to use this feature judiciously. For example, you may want to make sure the `Set()` and `Clear()` calls are right next to the code that uses your mock. ## Setting the Default Actions for a Mock Method ## You've learned how to change the default value of a given type. However, this may be too coarse for your purpose: perhaps you have two mock methods with the same return type and you want them to have different behaviors. The `ON_CALL()` macro allows you to customize your mock's behavior at the method level: ``` using ::testing::_; using ::testing::AnyNumber; using ::testing::Gt; using ::testing::Return; ... ON_CALL(foo, Sign(_)) .WillByDefault(Return(-1)); ON_CALL(foo, Sign(0)) .WillByDefault(Return(0)); ON_CALL(foo, Sign(Gt(0))) .WillByDefault(Return(1)); EXPECT_CALL(foo, Sign(_)) .Times(AnyNumber()); foo.Sign(5); // This should return 1. foo.Sign(-9); // This should return -1. foo.Sign(0); // This should return 0. ``` As you may have guessed, when there are more than one `ON_CALL()` statements, the news order take precedence over the older ones. In other words, the **last** one that matches the function arguments will be used. This matching order allows you to set up the common behavior in a mock object's constructor or the test fixture's set-up phase and specialize the mock's behavior later. ## Using Functions/Methods/Functors as Actions ## If the built-in actions don't suit you, you can easily use an existing function, method, or functor as an action: ``` using ::testing::_; using ::testing::Invoke; class MockFoo : public Foo { public: MOCK_METHOD2(Sum, int(int x, int y)); MOCK_METHOD1(ComplexJob, bool(int x)); }; int CalculateSum(int x, int y) { return x + y; } class Helper { public: bool ComplexJob(int x); }; ... MockFoo foo; Helper helper; EXPECT_CALL(foo, Sum(_, _)) .WillOnce(Invoke(CalculateSum)); EXPECT_CALL(foo, ComplexJob(_)) .WillOnce(Invoke(&helper, &Helper::ComplexJob)); foo.Sum(5, 6); // Invokes CalculateSum(5, 6). foo.ComplexJob(10); // Invokes helper.ComplexJob(10); ``` The only requirement is that the type of the function, etc must be _compatible_ with the signature of the mock function, meaning that the latter's arguments can be implicitly converted to the corresponding arguments of the former, and the former's return type can be implicitly converted to that of the latter. So, you can invoke something whose type is _not_ exactly the same as the mock function, as long as it's safe to do so - nice, huh? ## Invoking a Function/Method/Functor Without Arguments ## `Invoke()` is very useful for doing actions that are more complex. It passes the mock function's arguments to the function or functor being invoked such that the callee has the full context of the call to work with. If the invoked function is not interested in some or all of the arguments, it can simply ignore them. Yet, a common pattern is that a test author wants to invoke a function without the arguments of the mock function. `Invoke()` allows her to do that using a wrapper function that throws away the arguments before invoking an underlining nullary function. Needless to say, this can be tedious and obscures the intent of the test. `InvokeWithoutArgs()` solves this problem. It's like `Invoke()` except that it doesn't pass the mock function's arguments to the callee. Here's an example: ``` using ::testing::_; using ::testing::InvokeWithoutArgs; class MockFoo : public Foo { public: MOCK_METHOD1(ComplexJob, bool(int n)); }; bool Job1() { ... } ... MockFoo foo; EXPECT_CALL(foo, ComplexJob(_)) .WillOnce(InvokeWithoutArgs(Job1)); foo.ComplexJob(10); // Invokes Job1(). ``` ## Invoking an Argument of the Mock Function ## Sometimes a mock function will receive a function pointer or a functor (in other words, a "callable") as an argument, e.g. ``` class MockFoo : public Foo { public: MOCK_METHOD2(DoThis, bool(int n, bool (*fp)(int))); }; ``` and you may want to invoke this callable argument: ``` using ::testing::_; ... MockFoo foo; EXPECT_CALL(foo, DoThis(_, _)) .WillOnce(...); // Will execute (*fp)(5), where fp is the // second argument DoThis() receives. ``` Arghh, you need to refer to a mock function argument but C++ has no lambda (yet), so you have to define your own action. :-( Or do you really? Well, Google Mock has an action to solve _exactly_ this problem: ``` InvokeArgument<N>(arg_1, arg_2, ..., arg_m) ``` will invoke the `N`-th (0-based) argument the mock function receives, with `arg_1`, `arg_2`, ..., and `arg_m`. No matter if the argument is a function pointer or a functor, Google Mock handles them both. With that, you could write: ``` using ::testing::_; using ::testing::InvokeArgument; ... EXPECT_CALL(foo, DoThis(_, _)) .WillOnce(InvokeArgument<1>(5)); // Will execute (*fp)(5), where fp is the // second argument DoThis() receives. ``` What if the callable takes an argument by reference? No problem - just wrap it inside `ByRef()`: ``` ... MOCK_METHOD1(Bar, bool(bool (*fp)(int, const Helper&))); ... using ::testing::_; using ::testing::ByRef; using ::testing::InvokeArgument; ... MockFoo foo; Helper helper; ... EXPECT_CALL(foo, Bar(_)) .WillOnce(InvokeArgument<0>(5, ByRef(helper))); // ByRef(helper) guarantees that a reference to helper, not a copy of it, // will be passed to the callable. ``` What if the callable takes an argument by reference and we do **not** wrap the argument in `ByRef()`? Then `InvokeArgument()` will _make a copy_ of the argument, and pass a _reference to the copy_, instead of a reference to the original value, to the callable. This is especially handy when the argument is a temporary value: ``` ... MOCK_METHOD1(DoThat, bool(bool (*f)(const double& x, const string& s))); ... using ::testing::_; using ::testing::InvokeArgument; ... MockFoo foo; ... EXPECT_CALL(foo, DoThat(_)) .WillOnce(InvokeArgument<0>(5.0, string("Hi"))); // Will execute (*f)(5.0, string("Hi")), where f is the function pointer // DoThat() receives. Note that the values 5.0 and string("Hi") are // temporary and dead once the EXPECT_CALL() statement finishes. Yet // it's fine to perform this action later, since a copy of the values // are kept inside the InvokeArgument action. ``` ## Ignoring an Action's Result ## Sometimes you have an action that returns _something_, but you need an action that returns `void` (perhaps you want to use it in a mock function that returns `void`, or perhaps it needs to be used in `DoAll()` and it's not the last in the list). `IgnoreResult()` lets you do that. For example: ``` using ::testing::_; using ::testing::Invoke; using ::testing::Return; int Process(const MyData& data); string DoSomething(); class MockFoo : public Foo { public: MOCK_METHOD1(Abc, void(const MyData& data)); MOCK_METHOD0(Xyz, bool()); }; ... MockFoo foo; EXPECT_CALL(foo, Abc(_)) // .WillOnce(Invoke(Process)); // The above line won't compile as Process() returns int but Abc() needs // to return void. .WillOnce(IgnoreResult(Invoke(Process))); EXPECT_CALL(foo, Xyz()) .WillOnce(DoAll(IgnoreResult(Invoke(DoSomething)), // Ignores the string DoSomething() returns. Return(true))); ``` Note that you **cannot** use `IgnoreResult()` on an action that already returns `void`. Doing so will lead to ugly compiler errors. ## Selecting an Action's Arguments ## Say you have a mock function `Foo()` that takes seven arguments, and you have a custom action that you want to invoke when `Foo()` is called. Trouble is, the custom action only wants three arguments: ``` using ::testing::_; using ::testing::Invoke; ... MOCK_METHOD7(Foo, bool(bool visible, const string& name, int x, int y, const map<pair<int, int>, double>& weight, double min_weight, double max_wight)); ... bool IsVisibleInQuadrant1(bool visible, int x, int y) { return visible && x >= 0 && y >= 0; } ... EXPECT_CALL(mock, Foo(_, _, _, _, _, _, _)) .WillOnce(Invoke(IsVisibleInQuadrant1)); // Uh, won't compile. :-( ``` To please the compiler God, you can to define an "adaptor" that has the same signature as `Foo()` and calls the custom action with the right arguments: ``` using ::testing::_; using ::testing::Invoke; bool MyIsVisibleInQuadrant1(bool visible, const string& name, int x, int y, const map<pair<int, int>, double>& weight, double min_weight, double max_wight) { return IsVisibleInQuadrant1(visible, x, y); } ... EXPECT_CALL(mock, Foo(_, _, _, _, _, _, _)) .WillOnce(Invoke(MyIsVisibleInQuadrant1)); // Now it works. ``` But isn't this awkward? Google Mock provides a generic _action adaptor_, so you can spend your time minding more important business than writing your own adaptors. Here's the syntax: ``` WithArgs<N1, N2, ..., Nk>(action) ``` creates an action that passes the arguments of the mock function at the given indices (0-based) to the inner `action` and performs it. Using `WithArgs`, our original example can be written as: ``` using ::testing::_; using ::testing::Invoke; using ::testing::WithArgs; ... EXPECT_CALL(mock, Foo(_, _, _, _, _, _, _)) .WillOnce(WithArgs<0, 2, 3>(Invoke(IsVisibleInQuadrant1))); // No need to define your own adaptor. ``` For better readability, Google Mock also gives you: * `WithoutArgs(action)` when the inner `action` takes _no_ argument, and * `WithArg<N>(action)` (no `s` after `Arg`) when the inner `action` takes _one_ argument. As you may have realized, `InvokeWithoutArgs(...)` is just syntactic sugar for `WithoutArgs(Inovke(...))`. Here are more tips: * The inner action used in `WithArgs` and friends does not have to be `Invoke()` -- it can be anything. * You can repeat an argument in the argument list if necessary, e.g. `WithArgs<2, 3, 3, 5>(...)`. * You can change the order of the arguments, e.g. `WithArgs<3, 2, 1>(...)`. * The types of the selected arguments do _not_ have to match the signature of the inner action exactly. It works as long as they can be implicitly converted to the corresponding arguments of the inner action. For example, if the 4-th argument of the mock function is an `int` and `my_action` takes a `double`, `WithArg<4>(my_action)` will work. ## Ignoring Arguments in Action Functions ## The selecting-an-action's-arguments recipe showed us one way to make a mock function and an action with incompatible argument lists fit together. The downside is that wrapping the action in `WithArgs<...>()` can get tedious for people writing the tests. If you are defining a function, method, or functor to be used with `Invoke*()`, and you are not interested in some of its arguments, an alternative to `WithArgs` is to declare the uninteresting arguments as `Unused`. This makes the definition less cluttered and less fragile in case the types of the uninteresting arguments change. It could also increase the chance the action function can be reused. For example, given ``` MOCK_METHOD3(Foo, double(const string& label, double x, double y)); MOCK_METHOD3(Bar, double(int index, double x, double y)); ``` instead of ``` using ::testing::_; using ::testing::Invoke; double DistanceToOriginWithLabel(const string& label, double x, double y) { return sqrt(x*x + y*y); } double DistanceToOriginWithIndex(int index, double x, double y) { return sqrt(x*x + y*y); } ... EXEPCT_CALL(mock, Foo("abc", _, _)) .WillOnce(Invoke(DistanceToOriginWithLabel)); EXEPCT_CALL(mock, Bar(5, _, _)) .WillOnce(Invoke(DistanceToOriginWithIndex)); ``` you could write ``` using ::testing::_; using ::testing::Invoke; using ::testing::Unused; double DistanceToOrigin(Unused, double x, double y) { return sqrt(x*x + y*y); } ... EXEPCT_CALL(mock, Foo("abc", _, _)) .WillOnce(Invoke(DistanceToOrigin)); EXEPCT_CALL(mock, Bar(5, _, _)) .WillOnce(Invoke(DistanceToOrigin)); ``` ## Sharing Actions ## Just like matchers, a Google Mock action object consists of a pointer to a ref-counted implementation object. Therefore copying actions is also allowed and very efficient. When the last action that references the implementation object dies, the implementation object will be deleted. If you have some complex action that you want to use again and again, you may not have to build it from scratch everytime. If the action doesn't have an internal state (i.e. if it always does the same thing no matter how many times it has been called), you can assign it to an action variable and use that variable repeatedly. For example: ``` Action<bool(int*)> set_flag = DoAll(SetArgPointee<0>(5), Return(true)); ... use set_flag in .WillOnce() and .WillRepeatedly() ... ``` However, if the action has its own state, you may be surprised if you share the action object. Suppose you have an action factory `IncrementCounter(init)` which creates an action that increments and returns a counter whose initial value is `init`, using two actions created from the same expression and using a shared action will exihibit different behaviors. Example: ``` EXPECT_CALL(foo, DoThis()) .WillRepeatedly(IncrementCounter(0)); EXPECT_CALL(foo, DoThat()) .WillRepeatedly(IncrementCounter(0)); foo.DoThis(); // Returns 1. foo.DoThis(); // Returns 2. foo.DoThat(); // Returns 1 - Blah() uses a different // counter than Bar()'s. ``` versus ``` Action<int()> increment = IncrementCounter(0); EXPECT_CALL(foo, DoThis()) .WillRepeatedly(increment); EXPECT_CALL(foo, DoThat()) .WillRepeatedly(increment); foo.DoThis(); // Returns 1. foo.DoThis(); // Returns 2. foo.DoThat(); // Returns 3 - the counter is shared. ``` # Misc Recipes on Using Google Mock # ## Making the Compilation Faster ## Believe it or not, the _vast majority_ of the time spent on compiling a mock class is in generating its constructor and destructor, as they perform non-trivial tasks (e.g. verification of the expectations). What's more, mock methods with different signatures have different types and thus their constructors/destructors need to be generated by the compiler separately. As a result, if you mock many different types of methods, compiling your mock class can get really slow. If you are experiencing slow compilation, you can move the definition of your mock class' constructor and destructor out of the class body and into a `.cpp` file. This way, even if you `#include` your mock class in N files, the compiler only needs to generate its constructor and destructor once, resulting in a much faster compilation. Let's illustrate the idea using an example. Here's the definition of a mock class before applying this recipe: ``` // File mock_foo.h. ... class MockFoo : public Foo { public: // Since we don't declare the constructor or the destructor, // the compiler will generate them in every translation unit // where this mock class is used. MOCK_METHOD0(DoThis, int()); MOCK_METHOD1(DoThat, bool(const char* str)); ... more mock methods ... }; ``` After the change, it would look like: ``` // File mock_foo.h. ... class MockFoo : public Foo { public: // The constructor and destructor are declared, but not defined, here. MockFoo(); virtual ~MockFoo(); MOCK_METHOD0(DoThis, int()); MOCK_METHOD1(DoThat, bool(const char* str)); ... more mock methods ... }; ``` and ``` // File mock_foo.cpp. #include "path/to/mock_foo.h" // The definitions may appear trivial, but the functions actually do a // lot of things through the constructors/destructors of the member // variables used to implement the mock methods. MockFoo::MockFoo() {} MockFoo::~MockFoo() {} ``` ## Forcing a Verification ## When it's being destoyed, your friendly mock object will automatically verify that all expectations on it have been satisfied, and will generate [Google Test](http://code.google.com/p/googletest/) failures if not. This is convenient as it leaves you with one less thing to worry about. That is, unless you are not sure if your mock object will be destoyed. How could it be that your mock object won't eventually be destroyed? Well, it might be created on the heap and owned by the code you are testing. Suppose there's a bug in that code and it doesn't delete the mock object properly - you could end up with a passing test when there's actually a bug. Using a heap checker is a good idea and can alleviate the concern, but its implementation may not be 100% reliable. So, sometimes you do want to _force_ Google Mock to verify a mock object before it is (hopefully) destructed. You can do this with `Mock::VerifyAndClearExpectations(&mock_object)`: ``` TEST(MyServerTest, ProcessesRequest) { using ::testing::Mock; MockFoo* const foo = new MockFoo; EXPECT_CALL(*foo, ...)...; // ... other expectations ... // server now owns foo. MyServer server(foo); server.ProcessRequest(...); // In case that server's destructor will forget to delete foo, // this will verify the expectations anyway. Mock::VerifyAndClearExpectations(foo); } // server is destroyed when it goes out of scope here. ``` **Tip:** The `Mock::VerifyAndClearExpectations()` function returns a `bool` to indicate whether the verification was successful (`true` for yes), so you can wrap that function call inside a `ASSERT_TRUE()` if there is no point going further when the verification has failed. ## Using Check Points ## Sometimes you may want to "reset" a mock object at various check points in your test: at each check point, you verify that all existing expectations on the mock object have been satisfied, and then you set some new expectations on it as if it's newly created. This allows you to work with a mock object in "phases" whose sizes are each manageable. One such scenario is that in your test's `SetUp()` function, you may want to put the object you are testing into a certain state, with the help from a mock object. Once in the desired state, you want to clear all expectations on the mock, such that in the `TEST_F` body you can set fresh expectations on it. As you may have figured out, the `Mock::VerifyAndClearExpectations()` function we saw in the previous recipe can help you here. Or, if you are using `ON_CALL()` to set default actions on the mock object and want to clear the default actions as well, use `Mock::VerifyAndClear(&mock_object)` instead. This function does what `Mock::VerifyAndClearExpectations(&mock_object)` does and returns the same `bool`, **plus** it clears the `ON_CALL()` statements on `mock_object` too. Another trick you can use to achieve the same effect is to put the expectations in sequences and insert calls to a dummy "check-point" function at specific places. Then you can verify that the mock function calls do happen at the right time. For example, if you are exercising code: ``` Foo(1); Foo(2); Foo(3); ``` and want to verify that `Foo(1)` and `Foo(3)` both invoke `mock.Bar("a")`, but `Foo(2)` doesn't invoke anything. You can write: ``` using ::testing::MockFunction; TEST(FooTest, InvokesBarCorrectly) { MyMock mock; // Class MockFunction<F> has exactly one mock method. It is named // Call() and has type F. MockFunction<void(string check_point_name)> check; { InSequence s; EXPECT_CALL(mock, Bar("a")); EXPECT_CALL(check, Call("1")); EXPECT_CALL(check, Call("2")); EXPECT_CALL(mock, Bar("a")); } Foo(1); check.Call("1"); Foo(2); check.Call("2"); Foo(3); } ``` The expectation spec says that the first `Bar("a")` must happen before check point "1", the second `Bar("a")` must happen after check point "2", and nothing should happen between the two check points. The explicit check points make it easy to tell which `Bar("a")` is called by which call to `Foo()`. ## Mocking Destructors ## Sometimes you want to make sure a mock object is destructed at the right time, e.g. after `bar->A()` is called but before `bar->B()` is called. We already know that you can specify constraints on the order of mock function calls, so all we need to do is to mock the destructor of the mock function. This sounds simple, except for one problem: a destructor is a special function with special syntax and special semantics, and the `MOCK_METHOD0` macro doesn't work for it: ``` MOCK_METHOD0(~MockFoo, void()); // Won't compile! ``` The good news is that you can use a simple pattern to achieve the same effect. First, add a mock function `Die()` to your mock class and call it in the destructor, like this: ``` class MockFoo : public Foo { ... // Add the following two lines to the mock class. MOCK_METHOD0(Die, void()); virtual ~MockFoo() { Die(); } }; ``` (If the name `Die()` clashes with an existing symbol, choose another name.) Now, we have translated the problem of testing when a `MockFoo` object dies to testing when its `Die()` method is called: ``` MockFoo* foo = new MockFoo; MockBar* bar = new MockBar; ... { InSequence s; // Expects *foo to die after bar->A() and before bar->B(). EXPECT_CALL(*bar, A()); EXPECT_CALL(*foo, Die()); EXPECT_CALL(*bar, B()); } ``` And that's that. ## Using Google Mock and Threads ## **IMPORTANT NOTE:** What we describe in this recipe is **ONLY** true on platforms where Google Mock is thread-safe. Currently these are only platforms that support the pthreads library (this includes Linux and Mac). To make it thread-safe on other platforms we only need to implement some synchronization operations in `"gtest/internal/gtest-port.h"`. In a **unit** test, it's best if you could isolate and test a piece of code in a single-threaded context. That avoids race conditions and dead locks, and makes debugging your test much easier. Yet many programs are multi-threaded, and sometimes to test something we need to pound on it from more than one thread. Google Mock works for this purpose too. Remember the steps for using a mock: 1. Create a mock object `foo`. 1. Set its default actions and expectations using `ON_CALL()` and `EXPECT_CALL()`. 1. The code under test calls methods of `foo`. 1. Optionally, verify and reset the mock. 1. Destroy the mock yourself, or let the code under test destroy it. The destructor will automatically verify it. If you follow the following simple rules, your mocks and threads can live happily togeter: * Execute your _test code_ (as opposed to the code being tested) in _one_ thread. This makes your test easy to follow. * Obviously, you can do step #1 without locking. * When doing step #2 and #5, make sure no other thread is accessing `foo`. Obvious too, huh? * #3 and #4 can be done either in one thread or in multiple threads - anyway you want. Google Mock takes care of the locking, so you don't have to do any - unless required by your test logic. If you violate the rules (for example, if you set expectations on a mock while another thread is calling its methods), you get undefined behavior. That's not fun, so don't do it. Google Mock guarantees that the action for a mock function is done in the same thread that called the mock function. For example, in ``` EXPECT_CALL(mock, Foo(1)) .WillOnce(action1); EXPECT_CALL(mock, Foo(2)) .WillOnce(action2); ``` if `Foo(1)` is called in thread 1 and `Foo(2)` is called in thread 2, Google Mock will execute `action1` in thread 1 and `action2` in thread 2. Google Mock does _not_ impose a sequence on actions performed in different threads (doing so may create deadlocks as the actions may need to cooperate). This means that the execution of `action1` and `action2` in the above example _may_ interleave. If this is a problem, you should add proper synchronization logic to `action1` and `action2` to make the test thread-safe. Also, remember that `DefaultValue<T>` is a global resource that potentially affects _all_ living mock objects in your program. Naturally, you won't want to mess with it from multiple threads or when there still are mocks in action. ## Controlling How Much Information Google Mock Prints ## When Google Mock sees something that has the potential of being an error (e.g. a mock function with no expectation is called, a.k.a. an uninteresting call, which is allowed but perhaps you forgot to explicitly ban the call), it prints some warning messages, including the arguments of the function and the return value. Hopefully this will remind you to take a look and see if there is indeed a problem. Sometimes you are confident that your tests are correct and may not appreciate such friendly messages. Some other times, you are debugging your tests or learning about the behavior of the code you are testing, and wish you could observe every mock call that happens (including argument values and the return value). Clearly, one size doesn't fit all. You can control how much Google Mock tells you using the `--gmock_verbose=LEVEL` command-line flag, where `LEVEL` is a string with three possible values: * `info`: Google Mock will print all informational messages, warnings, and errors (most verbose). At this setting, Google Mock will also log any calls to the `ON_CALL/EXPECT_CALL` macros. * `warning`: Google Mock will print both warnings and errors (less verbose). This is the default. * `error`: Google Mock will print errors only (least verbose). Alternatively, you can adjust the value of that flag from within your tests like so: ``` ::testing::FLAGS_gmock_verbose = "error"; ``` Now, judiciously use the right flag to enable Google Mock serve you better! ## Running Tests in Emacs ## If you build and run your tests in Emacs, the source file locations of Google Mock and [Google Test](http://code.google.com/p/googletest/) errors will be highlighted. Just press `<Enter>` on one of them and you'll be taken to the offending line. Or, you can just type `C-x `` to jump to the next error. To make it even easier, you can add the following lines to your `~/.emacs` file: ``` (global-set-key "\M-m" 'compile) ; m is for make (global-set-key [M-down] 'next-error) (global-set-key [M-up] '(lambda () (interactive) (next-error -1))) ``` Then you can type `M-m` to start a build, or `M-up`/`M-down` to move back and forth between errors. ## Fusing Google Mock Source Files ## Google Mock's implementation consists of dozens of files (excluding its own tests). Sometimes you may want them to be packaged up in fewer files instead, such that you can easily copy them to a new machine and start hacking there. For this we provide an experimental Python script `fuse_gmock_files.py` in the `scripts/` directory (starting with release 1.2.0). Assuming you have Python 2.4 or above installed on your machine, just go to that directory and run ``` python fuse_gmock_files.py OUTPUT_DIR ``` and you should see an `OUTPUT_DIR` directory being created with files `gtest/gtest.h`, `gmock/gmock.h`, and `gmock-gtest-all.cc` in it. These three files contain everything you need to use Google Mock (and Google Test). Just copy them to anywhere you want and you are ready to write tests and use mocks. You can use the [scrpts/test/Makefile](http://code.google.com/p/googlemock/source/browse/trunk/scripts/test/Makefile) file as an example on how to compile your tests against them. # Extending Google Mock # ## Writing New Matchers Quickly ## The `MATCHER*` family of macros can be used to define custom matchers easily. The syntax: ``` MATCHER(name, description_string_expression) { statements; } ``` will define a matcher with the given name that executes the statements, which must return a `bool` to indicate if the match succeeds. Inside the statements, you can refer to the value being matched by `arg`, and refer to its type by `arg_type`. The description string is a `string`-typed expression that documents what the matcher does, and is used to generate the failure message when the match fails. It can (and should) reference the special `bool` variable `negation`, and should evaluate to the description of the matcher when `negation` is `false`, or that of the matcher's negation when `negation` is `true`. For convenience, we allow the description string to be empty (`""`), in which case Google Mock will use the sequence of words in the matcher name as the description. For example: ``` MATCHER(IsDivisibleBy7, "") { return (arg % 7) == 0; } ``` allows you to write ``` // Expects mock_foo.Bar(n) to be called where n is divisible by 7. EXPECT_CALL(mock_foo, Bar(IsDivisibleBy7())); ``` or, ``` using ::testing::Not; ... EXPECT_THAT(some_expression, IsDivisibleBy7()); EXPECT_THAT(some_other_expression, Not(IsDivisibleBy7())); ``` If the above assertions fail, they will print something like: ``` Value of: some_expression Expected: is divisible by 7 Actual: 27 ... Value of: some_other_expression Expected: not (is divisible by 7) Actual: 21 ``` where the descriptions `"is divisible by 7"` and `"not (is divisible by 7)"` are automatically calculated from the matcher name `IsDivisibleBy7`. As you may have noticed, the auto-generated descriptions (especially those for the negation) may not be so great. You can always override them with a string expression of your own: ``` MATCHER(IsDivisibleBy7, std::string(negation ? "isn't" : "is") + " divisible by 7") { return (arg % 7) == 0; } ``` Optionally, you can stream additional information to a hidden argument named `result_listener` to explain the match result. For example, a better definition of `IsDivisibleBy7` is: ``` MATCHER(IsDivisibleBy7, "") { if ((arg % 7) == 0) return true; *result_listener << "the remainder is " << (arg % 7); return false; } ``` With this definition, the above assertion will give a better message: ``` Value of: some_expression Expected: is divisible by 7 Actual: 27 (the remainder is 6) ``` You should let `MatchAndExplain()` print _any additional information_ that can help a user understand the match result. Note that it should explain why the match succeeds in case of a success (unless it's obvious) - this is useful when the matcher is used inside `Not()`. There is no need to print the argument value itself, as Google Mock already prints it for you. **Notes:** 1. The type of the value being matched (`arg_type`) is determined by the context in which you use the matcher and is supplied to you by the compiler, so you don't need to worry about declaring it (nor can you). This allows the matcher to be polymorphic. For example, `IsDivisibleBy7()` can be used to match any type where the value of `(arg % 7) == 0` can be implicitly converted to a `bool`. In the `Bar(IsDivisibleBy7())` example above, if method `Bar()` takes an `int`, `arg_type` will be `int`; if it takes an `unsigned long`, `arg_type` will be `unsigned long`; and so on. 1. Google Mock doesn't guarantee when or how many times a matcher will be invoked. Therefore the matcher logic must be _purely functional_ (i.e. it cannot have any side effect, and the result must not depend on anything other than the value being matched and the matcher parameters). This requirement must be satisfied no matter how you define the matcher (e.g. using one of the methods described in the following recipes). In particular, a matcher can never call a mock function, as that will affect the state of the mock object and Google Mock. ## Writing New Parameterized Matchers Quickly ## Sometimes you'll want to define a matcher that has parameters. For that you can use the macro: ``` MATCHER_P(name, param_name, description_string) { statements; } ``` where the description string can be either `""` or a string expression that references `negation` and `param_name`. For example: ``` MATCHER_P(HasAbsoluteValue, value, "") { return abs(arg) == value; } ``` will allow you to write: ``` EXPECT_THAT(Blah("a"), HasAbsoluteValue(n)); ``` which may lead to this message (assuming `n` is 10): ``` Value of: Blah("a") Expected: has absolute value 10 Actual: -9 ``` Note that both the matcher description and its parameter are printed, making the message human-friendly. In the matcher definition body, you can write `foo_type` to reference the type of a parameter named `foo`. For example, in the body of `MATCHER_P(HasAbsoluteValue, value)` above, you can write `value_type` to refer to the type of `value`. Google Mock also provides `MATCHER_P2`, `MATCHER_P3`, ..., up to `MATCHER_P10` to support multi-parameter matchers: ``` MATCHER_Pk(name, param_1, ..., param_k, description_string) { statements; } ``` Please note that the custom description string is for a particular **instance** of the matcher, where the parameters have been bound to actual values. Therefore usually you'll want the parameter values to be part of the description. Google Mock lets you do that by referencing the matcher parameters in the description string expression. For example, ``` using ::testing::PrintToString; MATCHER_P2(InClosedRange, low, hi, std::string(negation ? "isn't" : "is") + " in range [" + PrintToString(low) + ", " + PrintToString(hi) + "]") { return low <= arg && arg <= hi; } ... EXPECT_THAT(3, InClosedRange(4, 6)); ``` would generate a failure that contains the message: ``` Expected: is in range [4, 6] ``` If you specify `""` as the description, the failure message will contain the sequence of words in the matcher name followed by the parameter values printed as a tuple. For example, ``` MATCHER_P2(InClosedRange, low, hi, "") { ... } ... EXPECT_THAT(3, InClosedRange(4, 6)); ``` would generate a failure that contains the text: ``` Expected: in closed range (4, 6) ``` For the purpose of typing, you can view ``` MATCHER_Pk(Foo, p1, ..., pk, description_string) { ... } ``` as shorthand for ``` template <typename p1_type, ..., typename pk_type> FooMatcherPk<p1_type, ..., pk_type> Foo(p1_type p1, ..., pk_type pk) { ... } ``` When you write `Foo(v1, ..., vk)`, the compiler infers the types of the parameters `v1`, ..., and `vk` for you. If you are not happy with the result of the type inference, you can specify the types by explicitly instantiating the template, as in `Foo<long, bool>(5, false)`. As said earlier, you don't get to (or need to) specify `arg_type` as that's determined by the context in which the matcher is used. You can assign the result of expression `Foo(p1, ..., pk)` to a variable of type `FooMatcherPk<p1_type, ..., pk_type>`. This can be useful when composing matchers. Matchers that don't have a parameter or have only one parameter have special types: you can assign `Foo()` to a `FooMatcher`-typed variable, and assign `Foo(p)` to a `FooMatcherP<p_type>`-typed variable. While you can instantiate a matcher template with reference types, passing the parameters by pointer usually makes your code more readable. If, however, you still want to pass a parameter by reference, be aware that in the failure message generated by the matcher you will see the value of the referenced object but not its address. You can overload matchers with different numbers of parameters: ``` MATCHER_P(Blah, a, description_string_1) { ... } MATCHER_P2(Blah, a, b, description_string_2) { ... } ``` While it's tempting to always use the `MATCHER*` macros when defining a new matcher, you should also consider implementing `MatcherInterface` or using `MakePolymorphicMatcher()` instead (see the recipes that follow), especially if you need to use the matcher a lot. While these approaches require more work, they give you more control on the types of the value being matched and the matcher parameters, which in general leads to better compiler error messages that pay off in the long run. They also allow overloading matchers based on parameter types (as opposed to just based on the number of parameters). ## Writing New Monomorphic Matchers ## A matcher of argument type `T` implements `::testing::MatcherInterface<T>` and does two things: it tests whether a value of type `T` matches the matcher, and can describe what kind of values it matches. The latter ability is used for generating readable error messages when expectations are violated. The interface looks like this: ``` class MatchResultListener { public: ... // Streams x to the underlying ostream; does nothing if the ostream // is NULL. template <typename T> MatchResultListener& operator<<(const T& x); // Returns the underlying ostream. ::std::ostream* stream(); }; template <typename T> class MatcherInterface { public: virtual ~MatcherInterface(); // Returns true iff the matcher matches x; also explains the match // result to 'listener'. virtual bool MatchAndExplain(T x, MatchResultListener* listener) const = 0; // Describes this matcher to an ostream. virtual void DescribeTo(::std::ostream* os) const = 0; // Describes the negation of this matcher to an ostream. virtual void DescribeNegationTo(::std::ostream* os) const; }; ``` If you need a custom matcher but `Truly()` is not a good option (for example, you may not be happy with the way `Truly(predicate)` describes itself, or you may want your matcher to be polymorphic as `Eq(value)` is), you can define a matcher to do whatever you want in two steps: first implement the matcher interface, and then define a factory function to create a matcher instance. The second step is not strictly needed but it makes the syntax of using the matcher nicer. For example, you can define a matcher to test whether an `int` is divisible by 7 and then use it like this: ``` using ::testing::MakeMatcher; using ::testing::Matcher; using ::testing::MatcherInterface; using ::testing::MatchResultListener; class DivisibleBy7Matcher : public MatcherInterface<int> { public: virtual bool MatchAndExplain(int n, MatchResultListener* listener) const { return (n % 7) == 0; } virtual void DescribeTo(::std::ostream* os) const { *os << "is divisible by 7"; } virtual void DescribeNegationTo(::std::ostream* os) const { *os << "is not divisible by 7"; } }; inline Matcher<int> DivisibleBy7() { return MakeMatcher(new DivisibleBy7Matcher); } ... EXPECT_CALL(foo, Bar(DivisibleBy7())); ``` You may improve the matcher message by streaming additional information to the `listener` argument in `MatchAndExplain()`: ``` class DivisibleBy7Matcher : public MatcherInterface<int> { public: virtual bool MatchAndExplain(int n, MatchResultListener* listener) const { const int remainder = n % 7; if (remainder != 0) { *listener << "the remainder is " << remainder; } return remainder == 0; } ... }; ``` Then, `EXPECT_THAT(x, DivisibleBy7());` may general a message like this: ``` Value of: x Expected: is divisible by 7 Actual: 23 (the remainder is 2) ``` ## Writing New Polymorphic Matchers ## You've learned how to write your own matchers in the previous recipe. Just one problem: a matcher created using `MakeMatcher()` only works for one particular type of arguments. If you want a _polymorphic_ matcher that works with arguments of several types (for instance, `Eq(x)` can be used to match a `value` as long as `value` == `x` compiles -- `value` and `x` don't have to share the same type), you can learn the trick from `"gmock/gmock-matchers.h"` but it's a bit involved. Fortunately, most of the time you can define a polymorphic matcher easily with the help of `MakePolymorphicMatcher()`. Here's how you can define `NotNull()` as an example: ``` using ::testing::MakePolymorphicMatcher; using ::testing::MatchResultListener; using ::testing::NotNull; using ::testing::PolymorphicMatcher; class NotNullMatcher { public: // To implement a polymorphic matcher, first define a COPYABLE class // that has three members MatchAndExplain(), DescribeTo(), and // DescribeNegationTo(), like the following. // In this example, we want to use NotNull() with any pointer, so // MatchAndExplain() accepts a pointer of any type as its first argument. // In general, you can define MatchAndExplain() as an ordinary method or // a method template, or even overload it. template <typename T> bool MatchAndExplain(T* p, MatchResultListener* /* listener */) const { return p != NULL; } // Describes the property of a value matching this matcher. void DescribeTo(::std::ostream* os) const { *os << "is not NULL"; } // Describes the property of a value NOT matching this matcher. void DescribeNegationTo(::std::ostream* os) const { *os << "is NULL"; } }; // To construct a polymorphic matcher, pass an instance of the class // to MakePolymorphicMatcher(). Note the return type. inline PolymorphicMatcher<NotNullMatcher> NotNull() { return MakePolymorphicMatcher(NotNullMatcher()); } ... EXPECT_CALL(foo, Bar(NotNull())); // The argument must be a non-NULL pointer. ``` **Note:** Your polymorphic matcher class does **not** need to inherit from `MatcherInterface` or any other class, and its methods do **not** need to be virtual. Like in a monomorphic matcher, you may explain the match result by streaming additional information to the `listener` argument in `MatchAndExplain()`. ## Writing New Cardinalities ## A cardinality is used in `Times()` to tell Google Mock how many times you expect a call to occur. It doesn't have to be exact. For example, you can say `AtLeast(5)` or `Between(2, 4)`. If the built-in set of cardinalities doesn't suit you, you are free to define your own by implementing the following interface (in namespace `testing`): ``` class CardinalityInterface { public: virtual ~CardinalityInterface(); // Returns true iff call_count calls will satisfy this cardinality. virtual bool IsSatisfiedByCallCount(int call_count) const = 0; // Returns true iff call_count calls will saturate this cardinality. virtual bool IsSaturatedByCallCount(int call_count) const = 0; // Describes self to an ostream. virtual void DescribeTo(::std::ostream* os) const = 0; }; ``` For example, to specify that a call must occur even number of times, you can write ``` using ::testing::Cardinality; using ::testing::CardinalityInterface; using ::testing::MakeCardinality; class EvenNumberCardinality : public CardinalityInterface { public: virtual bool IsSatisfiedByCallCount(int call_count) const { return (call_count % 2) == 0; } virtual bool IsSaturatedByCallCount(int call_count) const { return false; } virtual void DescribeTo(::std::ostream* os) const { *os << "called even number of times"; } }; Cardinality EvenNumber() { return MakeCardinality(new EvenNumberCardinality); } ... EXPECT_CALL(foo, Bar(3)) .Times(EvenNumber()); ``` ## Writing New Actions Quickly ## If the built-in actions don't work for you, and you find it inconvenient to use `Invoke()`, you can use a macro from the `ACTION*` family to quickly define a new action that can be used in your code as if it's a built-in action. By writing ``` ACTION(name) { statements; } ``` in a namespace scope (i.e. not inside a class or function), you will define an action with the given name that executes the statements. The value returned by `statements` will be used as the return value of the action. Inside the statements, you can refer to the K-th (0-based) argument of the mock function as `argK`. For example: ``` ACTION(IncrementArg1) { return ++(*arg1); } ``` allows you to write ``` ... WillOnce(IncrementArg1()); ``` Note that you don't need to specify the types of the mock function arguments. Rest assured that your code is type-safe though: you'll get a compiler error if `*arg1` doesn't support the `++` operator, or if the type of `++(*arg1)` isn't compatible with the mock function's return type. Another example: ``` ACTION(Foo) { (*arg2)(5); Blah(); *arg1 = 0; return arg0; } ``` defines an action `Foo()` that invokes argument #2 (a function pointer) with 5, calls function `Blah()`, sets the value pointed to by argument #1 to 0, and returns argument #0. For more convenience and flexibility, you can also use the following pre-defined symbols in the body of `ACTION`: | `argK_type` | The type of the K-th (0-based) argument of the mock function | |:------------|:-------------------------------------------------------------| | `args` | All arguments of the mock function as a tuple | | `args_type` | The type of all arguments of the mock function as a tuple | | `return_type` | The return type of the mock function | | `function_type` | The type of the mock function | For example, when using an `ACTION` as a stub action for mock function: ``` int DoSomething(bool flag, int* ptr); ``` we have: | **Pre-defined Symbol** | **Is Bound To** | |:-----------------------|:----------------| | `arg0` | the value of `flag` | | `arg0_type` | the type `bool` | | `arg1` | the value of `ptr` | | `arg1_type` | the type `int*` | | `args` | the tuple `(flag, ptr)` | | `args_type` | the type `std::tr1::tuple<bool, int*>` | | `return_type` | the type `int` | | `function_type` | the type `int(bool, int*)` | ## Writing New Parameterized Actions Quickly ## Sometimes you'll want to parameterize an action you define. For that we have another macro ``` ACTION_P(name, param) { statements; } ``` For example, ``` ACTION_P(Add, n) { return arg0 + n; } ``` will allow you to write ``` // Returns argument #0 + 5. ... WillOnce(Add(5)); ``` For convenience, we use the term _arguments_ for the values used to invoke the mock function, and the term _parameters_ for the values used to instantiate an action. Note that you don't need to provide the type of the parameter either. Suppose the parameter is named `param`, you can also use the Google-Mock-defined symbol `param_type` to refer to the type of the parameter as inferred by the compiler. For example, in the body of `ACTION_P(Add, n)` above, you can write `n_type` for the type of `n`. Google Mock also provides `ACTION_P2`, `ACTION_P3`, and etc to support multi-parameter actions. For example, ``` ACTION_P2(ReturnDistanceTo, x, y) { double dx = arg0 - x; double dy = arg1 - y; return sqrt(dx*dx + dy*dy); } ``` lets you write ``` ... WillOnce(ReturnDistanceTo(5.0, 26.5)); ``` You can view `ACTION` as a degenerated parameterized action where the number of parameters is 0. You can also easily define actions overloaded on the number of parameters: ``` ACTION_P(Plus, a) { ... } ACTION_P2(Plus, a, b) { ... } ``` ## Restricting the Type of an Argument or Parameter in an ACTION ## For maximum brevity and reusability, the `ACTION*` macros don't ask you to provide the types of the mock function arguments and the action parameters. Instead, we let the compiler infer the types for us. Sometimes, however, we may want to be more explicit about the types. There are several tricks to do that. For example: ``` ACTION(Foo) { // Makes sure arg0 can be converted to int. int n = arg0; ... use n instead of arg0 here ... } ACTION_P(Bar, param) { // Makes sure the type of arg1 is const char*. ::testing::StaticAssertTypeEq<const char*, arg1_type>(); // Makes sure param can be converted to bool. bool flag = param; } ``` where `StaticAssertTypeEq` is a compile-time assertion in Google Test that verifies two types are the same. ## Writing New Action Templates Quickly ## Sometimes you want to give an action explicit template parameters that cannot be inferred from its value parameters. `ACTION_TEMPLATE()` supports that and can be viewed as an extension to `ACTION()` and `ACTION_P*()`. The syntax: ``` ACTION_TEMPLATE(ActionName, HAS_m_TEMPLATE_PARAMS(kind1, name1, ..., kind_m, name_m), AND_n_VALUE_PARAMS(p1, ..., p_n)) { statements; } ``` defines an action template that takes _m_ explicit template parameters and _n_ value parameters, where _m_ is between 1 and 10, and _n_ is between 0 and 10. `name_i` is the name of the i-th template parameter, and `kind_i` specifies whether it's a `typename`, an integral constant, or a template. `p_i` is the name of the i-th value parameter. Example: ``` // DuplicateArg<k, T>(output) converts the k-th argument of the mock // function to type T and copies it to *output. ACTION_TEMPLATE(DuplicateArg, // Note the comma between int and k: HAS_2_TEMPLATE_PARAMS(int, k, typename, T), AND_1_VALUE_PARAMS(output)) { *output = T(std::tr1::get<k>(args)); } ``` To create an instance of an action template, write: ``` ActionName<t1, ..., t_m>(v1, ..., v_n) ``` where the `t`s are the template arguments and the `v`s are the value arguments. The value argument types are inferred by the compiler. For example: ``` using ::testing::_; ... int n; EXPECT_CALL(mock, Foo(_, _)) .WillOnce(DuplicateArg<1, unsigned char>(&n)); ``` If you want to explicitly specify the value argument types, you can provide additional template arguments: ``` ActionName<t1, ..., t_m, u1, ..., u_k>(v1, ..., v_n) ``` where `u_i` is the desired type of `v_i`. `ACTION_TEMPLATE` and `ACTION`/`ACTION_P*` can be overloaded on the number of value parameters, but not on the number of template parameters. Without the restriction, the meaning of the following is unclear: ``` OverloadedAction<int, bool>(x); ``` Are we using a single-template-parameter action where `bool` refers to the type of `x`, or a two-template-parameter action where the compiler is asked to infer the type of `x`? ## Using the ACTION Object's Type ## If you are writing a function that returns an `ACTION` object, you'll need to know its type. The type depends on the macro used to define the action and the parameter types. The rule is relatively simple: | **Given Definition** | **Expression** | **Has Type** | |:---------------------|:---------------|:-------------| | `ACTION(Foo)` | `Foo()` | `FooAction` | | `ACTION_TEMPLATE(Foo, HAS_m_TEMPLATE_PARAMS(...), AND_0_VALUE_PARAMS())` | `Foo<t1, ..., t_m>()` | `FooAction<t1, ..., t_m>` | | `ACTION_P(Bar, param)` | `Bar(int_value)` | `BarActionP<int>` | | `ACTION_TEMPLATE(Bar, HAS_m_TEMPLATE_PARAMS(...), AND_1_VALUE_PARAMS(p1))` | `Bar<t1, ..., t_m>(int_value)` | `FooActionP<t1, ..., t_m, int>` | | `ACTION_P2(Baz, p1, p2)` | `Baz(bool_value, int_value)` | `BazActionP2<bool, int>` | | `ACTION_TEMPLATE(Baz, HAS_m_TEMPLATE_PARAMS(...), AND_2_VALUE_PARAMS(p1, p2))` | `Baz<t1, ..., t_m>(bool_value, int_value)` | `FooActionP2<t1, ..., t_m, bool, int>` | | ... | ... | ... | Note that we have to pick different suffixes (`Action`, `ActionP`, `ActionP2`, and etc) for actions with different numbers of value parameters, or the action definitions cannot be overloaded on the number of them. ## Writing New Monomorphic Actions ## While the `ACTION*` macros are very convenient, sometimes they are inappropriate. For example, despite the tricks shown in the previous recipes, they don't let you directly specify the types of the mock function arguments and the action parameters, which in general leads to unoptimized compiler error messages that can baffle unfamiliar users. They also don't allow overloading actions based on parameter types without jumping through some hoops. An alternative to the `ACTION*` macros is to implement `::testing::ActionInterface<F>`, where `F` is the type of the mock function in which the action will be used. For example: ``` template <typename F>class ActionInterface { public: virtual ~ActionInterface(); // Performs the action. Result is the return type of function type // F, and ArgumentTuple is the tuple of arguments of F. // // For example, if F is int(bool, const string&), then Result would // be int, and ArgumentTuple would be tr1::tuple<bool, const string&>. virtual Result Perform(const ArgumentTuple& args) = 0; }; using ::testing::_; using ::testing::Action; using ::testing::ActionInterface; using ::testing::MakeAction; typedef int IncrementMethod(int*); class IncrementArgumentAction : public ActionInterface<IncrementMethod> { public: virtual int Perform(const tr1::tuple<int*>& args) { int* p = tr1::get<0>(args); // Grabs the first argument. return *p++; } }; Action<IncrementMethod> IncrementArgument() { return MakeAction(new IncrementArgumentAction); } ... EXPECT_CALL(foo, Baz(_)) .WillOnce(IncrementArgument()); int n = 5; foo.Baz(&n); // Should return 5 and change n to 6. ``` ## Writing New Polymorphic Actions ## The previous recipe showed you how to define your own action. This is all good, except that you need to know the type of the function in which the action will be used. Sometimes that can be a problem. For example, if you want to use the action in functions with _different_ types (e.g. like `Return()` and `SetArgPointee()`). If an action can be used in several types of mock functions, we say it's _polymorphic_. The `MakePolymorphicAction()` function template makes it easy to define such an action: ``` namespace testing { template <typename Impl> PolymorphicAction<Impl> MakePolymorphicAction(const Impl& impl); } // namespace testing ``` As an example, let's define an action that returns the second argument in the mock function's argument list. The first step is to define an implementation class: ``` class ReturnSecondArgumentAction { public: template <typename Result, typename ArgumentTuple> Result Perform(const ArgumentTuple& args) const { // To get the i-th (0-based) argument, use tr1::get<i>(args). return tr1::get<1>(args); } }; ``` This implementation class does _not_ need to inherit from any particular class. What matters is that it must have a `Perform()` method template. This method template takes the mock function's arguments as a tuple in a **single** argument, and returns the result of the action. It can be either `const` or not, but must be invokable with exactly one template argument, which is the result type. In other words, you must be able to call `Perform<R>(args)` where `R` is the mock function's return type and `args` is its arguments in a tuple. Next, we use `MakePolymorphicAction()` to turn an instance of the implementation class into the polymorphic action we need. It will be convenient to have a wrapper for this: ``` using ::testing::MakePolymorphicAction; using ::testing::PolymorphicAction; PolymorphicAction<ReturnSecondArgumentAction> ReturnSecondArgument() { return MakePolymorphicAction(ReturnSecondArgumentAction()); } ``` Now, you can use this polymorphic action the same way you use the built-in ones: ``` using ::testing::_; class MockFoo : public Foo { public: MOCK_METHOD2(DoThis, int(bool flag, int n)); MOCK_METHOD3(DoThat, string(int x, const char* str1, const char* str2)); }; ... MockFoo foo; EXPECT_CALL(foo, DoThis(_, _)) .WillOnce(ReturnSecondArgument()); EXPECT_CALL(foo, DoThat(_, _, _)) .WillOnce(ReturnSecondArgument()); ... foo.DoThis(true, 5); // Will return 5. foo.DoThat(1, "Hi", "Bye"); // Will return "Hi". ``` ## Teaching Google Mock How to Print Your Values ## When an uninteresting or unexpected call occurs, Google Mock prints the argument values and the stack trace to help you debug. Assertion macros like `EXPECT_THAT` and `EXPECT_EQ` also print the values in question when the assertion fails. Google Mock and Google Test do this using Google Test's user-extensible value printer. This printer knows how to print built-in C++ types, native arrays, STL containers, and any type that supports the `<<` operator. For other types, it prints the raw bytes in the value and hopes that you the user can figure it out. [Google Test's advanced guide](http://code.google.com/p/googletest/wiki/V1_6_AdvancedGuide#Teaching_Google_Test_How_to_Print_Your_Values) explains how to extend the printer to do a better job at printing your particular type than to dump the bytes.