From c3d8269e34b965db50385c1b2ec6d5089b500f6d Mon Sep 17 00:00:00 2001 From: Google Code Exporter Date: Mon, 24 Aug 2015 18:41:02 -0400 Subject: Migrating wiki contents from Google Code --- V1_5_CheatSheet.md | 525 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 525 insertions(+) create mode 100644 V1_5_CheatSheet.md (limited to 'V1_5_CheatSheet.md') diff --git a/V1_5_CheatSheet.md b/V1_5_CheatSheet.md new file mode 100644 index 00000000..3c7bed4c --- /dev/null +++ b/V1_5_CheatSheet.md @@ -0,0 +1,525 @@ + + +# Defining a Mock Class # + +## Mocking a Normal Class ## + +Given +``` +class Foo { + ... + virtual ~Foo(); + virtual int GetSize() const = 0; + virtual string Describe(const char* name) = 0; + virtual string Describe(int type) = 0; + virtual bool Process(Bar elem, int count) = 0; +}; +``` +(note that `~Foo()` **must** be virtual) we can define its mock as +``` +#include + +class MockFoo : public Foo { + MOCK_CONST_METHOD0(GetSize, int()); + MOCK_METHOD1(Describe, string(const char* name)); + MOCK_METHOD1(Describe, string(int type)); + MOCK_METHOD2(Process, bool(Bar elem, int count)); +}; +``` + +To create a "nice" mock object which ignores all uninteresting calls, +or a "strict" mock object, which treats them as failures: +``` +NiceMock nice_foo; // The type is a subclass of MockFoo. +StrictMock strict_foo; // The type is a subclass of MockFoo. +``` + +## Mocking a Class Template ## + +To mock +``` +template +class StackInterface { + public: + ... + virtual ~StackInterface(); + virtual int GetSize() const = 0; + virtual void Push(const Elem& x) = 0; +}; +``` +(note that `~StackInterface()` **must** be virtual) just append `_T` to the `MOCK_*` macros: +``` +template +class MockStack : public StackInterface { + public: + ... + MOCK_CONST_METHOD0_T(GetSize, int()); + MOCK_METHOD1_T(Push, void(const Elem& x)); +}; +``` + +## Specifying Calling Conventions for Mock Functions ## + +If your mock function doesn't use the default calling convention, you +can specify it by appending `_WITH_CALLTYPE` to any of the macros +described in the previous two sections and supplying the calling +convention as the first argument to the macro. For example, +``` + MOCK_METHOD_1_WITH_CALLTYPE(STDMETHODCALLTYPE, Foo, bool(int n)); + MOCK_CONST_METHOD2_WITH_CALLTYPE(STDMETHODCALLTYPE, Bar, int(double x, double y)); +``` +where `STDMETHODCALLTYPE` is defined by `` on Windows. + +# Using Mocks in Tests # + +The typical flow is: + 1. Import the Google Mock names you need to use. All Google Mock names are in the `testing` namespace unless they are macros or otherwise noted. + 1. Create the mock objects. + 1. Optionally, set the default actions of the mock objects. + 1. Set your expectations on the mock objects (How will they be called? What wil they do?). + 1. Exercise code that uses the mock objects; if necessary, check the result using [Google Test](http://code.google.com/p/googletest/) assertions. + 1. When a mock objects is destructed, Google Mock automatically verifies that all expectations on it have been satisfied. + +Here is an example: +``` +using ::testing::Return; // #1 + +TEST(BarTest, DoesThis) { + MockFoo foo; // #2 + + ON_CALL(foo, GetSize()) // #3 + .WillByDefault(Return(1)); + // ... other default actions ... + + EXPECT_CALL(foo, Describe(5)) // #4 + .Times(3) + .WillRepeatedly(Return("Category 5")); + // ... other expectations ... + + EXPECT_EQ("good", MyProductionFunction(&foo)); // #5 +} // #6 +``` + +# Setting Default Actions # + +Google Mock has a **built-in default action** for any function that +returns `void`, `bool`, a numeric value, or a pointer. + +To customize the default action for functions with return type `T` globally: +``` +using ::testing::DefaultValue; + +DefaultValue::Set(value); // Sets the default value to be returned. +// ... use the mocks ... +DefaultValue::Clear(); // Resets the default value. +``` + +To customize the default action for a particular method, use `ON_CALL()`: +``` +ON_CALL(mock_object, method(matchers)) + .With(multi_argument_matcher) ? + .WillByDefault(action); +``` + +# Setting Expectations # + +`EXPECT_CALL()` sets **expectations** on a mock method (How will it be +called? What will it do?): +``` +EXPECT_CALL(mock_object, method(matchers)) + .With(multi_argument_matcher) ? + .Times(cardinality) ? + .InSequence(sequences) * + .After(expectations) * + .WillOnce(action) * + .WillRepeatedly(action) ? + .RetiresOnSaturation(); ? +``` + +If `Times()` is omitted, the cardinality is assumed to be: + + * `Times(1)` when there is neither `WillOnce()` nor `WillRepeatedly()`; + * `Times(n)` when there are `n WillOnce()`s but no `WillRepeatedly()`, where `n` >= 1; or + * `Times(AtLeast(n))` when there are `n WillOnce()`s and a `WillRepeatedly()`, where `n` >= 0. + +A method with no `EXPECT_CALL()` is free to be invoked _any number of times_, and the default action will be taken each time. + +# Matchers # + +A **matcher** matches a _single_ argument. You can use it inside +`ON_CALL()` or `EXPECT_CALL()`, or use it to validate a value +directly: + +| `EXPECT_THAT(value, matcher)` | Asserts that `value` matches `matcher`. | +|:------------------------------|:----------------------------------------| +| `ASSERT_THAT(value, matcher)` | The same as `EXPECT_THAT(value, matcher)`, except that it generates a **fatal** failure. | + +Built-in matchers (where `argument` is the function argument) are +divided into several categories: + +## Wildcard ## +|`_`|`argument` can be any value of the correct type.| +|:--|:-----------------------------------------------| +|`A()` or `An()`|`argument` can be any value of type `type`. | + +## Generic Comparison ## + +|`Eq(value)` or `value`|`argument == value`| +|:---------------------|:------------------| +|`Ge(value)` |`argument >= value`| +|`Gt(value)` |`argument > value` | +|`Le(value)` |`argument <= value`| +|`Lt(value)` |`argument < value` | +|`Ne(value)` |`argument != value`| +|`IsNull()` |`argument` is a `NULL` pointer (raw or smart).| +|`NotNull()` |`argument` is a non-null pointer (raw or smart).| +|`Ref(variable)` |`argument` is a reference to `variable`.| +|`TypedEq(value)`|`argument` has type `type` and is equal to `value`. You may need to use this instead of `Eq(value)` when the mock function is overloaded.| + +Except `Ref()`, these matchers make a _copy_ of `value` in case it's +modified or destructed later. If the compiler complains that `value` +doesn't have a public copy constructor, try wrap it in `ByRef()`, +e.g. `Eq(ByRef(non_copyable_value))`. If you do that, make sure +`non_copyable_value` is not changed afterwards, or the meaning of your +matcher will be changed. + +## Floating-Point Matchers ## + +|`DoubleEq(a_double)`|`argument` is a `double` value approximately equal to `a_double`, treating two NaNs as unequal.| +|:-------------------|:----------------------------------------------------------------------------------------------| +|`FloatEq(a_float)` |`argument` is a `float` value approximately equal to `a_float`, treating two NaNs as unequal. | +|`NanSensitiveDoubleEq(a_double)`|`argument` is a `double` value approximately equal to `a_double`, treating two NaNs as equal. | +|`NanSensitiveFloatEq(a_float)`|`argument` is a `float` value approximately equal to `a_float`, treating two NaNs as equal. | + +The above matchers use ULP-based comparison (the same as used in +[Google Test](http://code.google.com/p/googletest/)). They +automatically pick a reasonable error bound based on the absolute +value of the expected value. `DoubleEq()` and `FloatEq()` conform to +the IEEE standard, which requires comparing two NaNs for equality to +return false. The `NanSensitive*` version instead treats two NaNs as +equal, which is often what a user wants. + +## String Matchers ## + +The `argument` can be either a C string or a C++ string object: + +|`ContainsRegex(string)`|`argument` matches the given regular expression.| +|:----------------------|:-----------------------------------------------| +|`EndsWith(suffix)` |`argument` ends with string `suffix`. | +|`HasSubstr(string)` |`argument` contains `string` as a sub-string. | +|`MatchesRegex(string)` |`argument` matches the given regular expression with the match starting at the first character and ending at the last character.| +|`StartsWith(prefix)` |`argument` starts with string `prefix`. | +|`StrCaseEq(string)` |`argument` is equal to `string`, ignoring case. | +|`StrCaseNe(string)` |`argument` is not equal to `string`, ignoring case.| +|`StrEq(string)` |`argument` is equal to `string`. | +|`StrNe(string)` |`argument` is not equal to `string`. | + +`StrCaseEq()`, `StrCaseNe()`, `StrEq()`, and `StrNe()` work for wide +strings as well. + +## Container Matchers ## + +Most STL-style containers support `==`, so you can use +`Eq(expected_container)` or simply `expected_container` to match a +container exactly. If you want to write the elements in-line, +match them more flexibly, or get more informative messages, you can use: + +| `Contains(e)` | `argument` contains an element that matches `e`, which can be either a value or a matcher. | +|:--------------|:-------------------------------------------------------------------------------------------| +|`ElementsAre(e0, e1, ..., en)`|`argument` has `n + 1` elements, where the i-th element matches `ei`, which can be a value or a matcher. 0 to 10 arguments are allowed.| +|`ElementsAreArray(array)` or `ElementsAreArray(array, count)`|The same as `ElementsAre()` except that the expected element values/matchers come from a C-style array.| +| `ContainerEq(container)` | The same as `Eq(container)` except that the failure message also includes which elements are in one container but not the other. | + +These matchers can also match: + + 1. a native array passed by reference (e.g. in `Foo(const int (&a)[5])`), and + 1. an array passed as a pointer and a count (e.g. in `Bar(const T* buffer, int len)` -- see [Multi-argument Matchers](#Multiargument_Matchers.md)). + +where the array may be multi-dimensional (i.e. its elements can be arrays). + +## Member Matchers ## + +|`Field(&class::field, m)`|`argument.field` (or `argument->field` when `argument` is a plain pointer) matches matcher `m`, where `argument` is an object of type _class_.| +|:------------------------|:---------------------------------------------------------------------------------------------------------------------------------------------| +|`Key(e)` |`argument.first` matches `e`, which can be either a value or a matcher. E.g. `Contains(Key(Le(5)))` can verify that a `map` contains a key `<= 5`.| +|`Pair(m1, m2)` |`argument` is an `std::pair` whose `first` field matches `m1` and `second` field matches `m2`. | +|`Property(&class::property, m)`|`argument.property()` (or `argument->property()` when `argument` is a plain pointer) matches matcher `m`, where `argument` is an object of type _class_.| + +## Matching the Result of a Function or Functor ## + +|`ResultOf(f, m)`|`f(argument)` matches matcher `m`, where `f` is a function or functor.| +|:---------------|:---------------------------------------------------------------------| + +## Pointer Matchers ## + +|`Pointee(m)`|`argument` (either a smart pointer or a raw pointer) points to a value that matches matcher `m`.| +|:-----------|:-----------------------------------------------------------------------------------------------| + +## Multiargument Matchers ## + +These are matchers on tuple types. They can be used in +`.With()`. The following can be used on functions with two
+arguments `x` and `y`: + +|`Eq()`|`x == y`| +|:-----|:-------| +|`Ge()`|`x >= y`| +|`Gt()`|`x > y` | +|`Le()`|`x <= y`| +|`Lt()`|`x < y` | +|`Ne()`|`x != y`| + +You can use the following selectors to pick a subset of the arguments +(or reorder them) to participate in the matching: + +|`AllArgs(m)`|Equivalent to `m`. Useful as syntactic sugar in `.With(AllArgs(m))`.| +|:-----------|:-------------------------------------------------------------------| +|`Args(m)`|The `k` selected (using 0-based indices) arguments match `m`, e.g. `Args<1, 2>(Contains(5))`.| + +## Composite Matchers ## + +You can make a matcher from one or more other matchers: + +|`AllOf(m1, m2, ..., mn)`|`argument` matches all of the matchers `m1` to `mn`.| +|:-----------------------|:---------------------------------------------------| +|`AnyOf(m1, m2, ..., mn)`|`argument` matches at least one of the matchers `m1` to `mn`.| +|`Not(m)` |`argument` doesn't match matcher `m`. | + +## Adapters for Matchers ## + +|`MatcherCast(m)`|casts matcher `m` to type `Matcher`.| +|:------------------|:--------------------------------------| +|`SafeMatcherCast(m)`| [safely casts](V1_5_CookBook#Casting_Matchers.md) matcher `m` to type `Matcher`. | +|`Truly(predicate)` |`predicate(argument)` returns something considered by C++ to be true, where `predicate` is a function or functor.| + +## Matchers as Predicates ## + +|`Matches(m)`|a unary functor that returns `true` if the argument matches `m`.| +|:-----------|:---------------------------------------------------------------| +|`ExplainMatchResult(m, value, result_listener)`|returns `true` if `value` matches `m`, explaining the result to `result_listener`.| +|`Value(x, m)`|returns `true` if the value of `x` matches `m`. | + +## Defining Matchers ## + +| `MATCHER(IsEven, "") { return (arg % 2) == 0; }` | Defines a matcher `IsEven()` to match an even number. | +|:-------------------------------------------------|:------------------------------------------------------| +| `MATCHER_P(IsDivisibleBy, n, "") { *result_listener << "where the remainder is " << (arg % n); return (arg % n) == 0; }` | Defines a macher `IsDivisibleBy(n)` to match a number divisible by `n`. | +| `MATCHER_P2(IsBetween, a, b, "is between %(a)s and %(b)s") { return a <= arg && arg <= b; }` | Defines a matcher `IsBetween(a, b)` to match a value in the range [`a`, `b`]. | + +**Notes:** + + 1. The `MATCHER*` macros cannot be used inside a function or class. + 1. The matcher body 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). + 1. You can use `PrintToString(x)` to convert a value `x` of any type to a string. + +## Matchers as Test Assertions ## + +|`ASSERT_THAT(expression, m)`|Generates a [fatal failure](http://code.google.com/p/googletest/wiki/GoogleTestPrimer#Assertions) if the value of `expression` doesn't match matcher `m`.| +|:---------------------------|:--------------------------------------------------------------------------------------------------------------------------------------------------------| +|`EXPECT_THAT(expression, m)`|Generates a non-fatal failure if the value of `expression` doesn't match matcher `m`. | + +# Actions # + +**Actions** specify what a mock function should do when invoked. + +## Returning a Value ## + +|`Return()`|Return from a `void` mock function.| +|:---------|:----------------------------------| +|`Return(value)`|Return `value`. | +|`ReturnArg()`|Return the `N`-th (0-based) argument.| +|`ReturnNew(a1, ..., ak)`|Return `new T(a1, ..., ak)`; a different object is created each time.| +|`ReturnNull()`|Return a null pointer. | +|`ReturnRef(variable)`|Return a reference to `variable`. | + +## Side Effects ## + +|`Assign(&variable, value)`|Assign `value` to variable.| +|:-------------------------|:--------------------------| +| `DeleteArg()` | Delete the `N`-th (0-based) argument, which must be a pointer. | +| `SaveArg(pointer)` | Save the `N`-th (0-based) argument to `*pointer`. | +| `SetArgReferee(value)` | Assign value to the variable referenced by the `N`-th (0-based) argument. | +|`SetArgumentPointee(value)`|Assign `value` to the variable pointed by the `N`-th (0-based) argument.| +|`SetArrayArgument(first, last)`|Copies the elements in source range [`first`, `last`) to the array pointed to by the `N`-th (0-based) argument, which can be either a pointer or an iterator. The action does not take ownership of the elements in the source range.| +|`SetErrnoAndReturn(error, value)`|Set `errno` to `error` and return `value`.| +|`Throw(exception)` |Throws the given exception, which can be any copyable value. Available since v1.1.0.| + +## Using a Function or a Functor as an Action ## + +|`Invoke(f)`|Invoke `f` with the arguments passed to the mock function, where `f` can be a global/static function or a functor.| +|:----------|:-----------------------------------------------------------------------------------------------------------------| +|`Invoke(object_pointer, &class::method)`|Invoke the {method on the object with the arguments passed to the mock function. | +|`InvokeWithoutArgs(f)`|Invoke `f`, which can be a global/static function or a functor. `f` must take no arguments. | +|`InvokeWithoutArgs(object_pointer, &class::method)`|Invoke the method on the object, which takes no arguments. | +|`InvokeArgument(arg1, arg2, ..., argk)`|Invoke the mock function's `N`-th (0-based) argument, which must be a function or a functor, with the `k` arguments.| + +The return value of the invoked function is used as the return value +of the action. + +When defining a function or functor to be used with `Invoke*()`, you can declare any unused parameters as `Unused`: +``` + double Distance(Unused, double x, double y) { return sqrt(x*x + y*y); } + ... + EXPECT_CALL(mock, Foo("Hi", _, _)).WillOnce(Invoke(Distance)); +``` + +In `InvokeArgument(...)`, if an argument needs to be passed by reference, wrap it inside `ByRef()`. For example, +``` + InvokeArgument<2>(5, string("Hi"), ByRef(foo)) +``` +calls the mock function's #2 argument, passing to it `5` and `string("Hi")` by value, and `foo` by reference. + +## Default Action ## + +|`DoDefault()`|Do the default action (specified by `ON_CALL()` or the built-in one).| +|:------------|:--------------------------------------------------------------------| + +**Note:** due to technical reasons, `DoDefault()` cannot be used inside a composite action - trying to do so will result in a run-time error. + +## Composite Actions ## + +|`DoAll(a1, a2, ..., an)`|Do all actions `a1` to `an` and return the result of `an` in each invocation. The first `n - 1` sub-actions must return void. | +|:-----------------------|:-----------------------------------------------------------------------------------------------------------------------------| +|`IgnoreResult(a)` |Perform action `a` and ignore its result. `a` must not return void. | +|`WithArg(a)` |Pass the `N`-th (0-based) argument of the mock function to action `a` and perform it. | +|`WithArgs(a)`|Pass the selected (0-based) arguments of the mock function to action `a` and perform it. | +|`WithoutArgs(a)` |Perform action `a` without any arguments. | + +## Defining Actions ## + +| `ACTION(Sum) { return arg0 + arg1; }` | Defines an action `Sum()` to return the sum of the mock function's argument #0 and #1. | +|:--------------------------------------|:---------------------------------------------------------------------------------------| +| `ACTION_P(Plus, n) { return arg0 + n; }` | Defines an action `Plus(n)` to return the sum of the mock function's argument #0 and `n`. | +| `ACTION_Pk(Foo, p1, ..., pk) { statements; }` | Defines a parameterized action `Foo(p1, ..., pk)` to execute the given `statements`. | + +The `ACTION*` macros cannot be used inside a function or class. + +# Cardinalities # + +These are used in `Times()` to specify how many times a mock function will be called: + +|`AnyNumber()`|The function can be called any number of times.| +|:------------|:----------------------------------------------| +|`AtLeast(n)` |The call is expected at least `n` times. | +|`AtMost(n)` |The call is expected at most `n` times. | +|`Between(m, n)`|The call is expected between `m` and `n` (inclusive) times.| +|`Exactly(n) or n`|The call is expected exactly `n` times. In particular, the call should never happen when `n` is 0.| + +# Expectation Order # + +By default, the expectations can be matched in _any_ order. If some +or all expectations must be matched in a given order, there are two +ways to specify it. They can be used either independently or +together. + +## The After Clause ## + +``` +using ::testing::Expectation; +... +Expectation init_x = EXPECT_CALL(foo, InitX()); +Expectation init_y = EXPECT_CALL(foo, InitY()); +EXPECT_CALL(foo, Bar()) + .After(init_x, init_y); +``` +says that `Bar()` can be called only after both `InitX()` and +`InitY()` have been called. + +If you don't know how many pre-requisites an expectation has when you +write it, you can use an `ExpectationSet` to collect them: + +``` +using ::testing::ExpectationSet; +... +ExpectationSet all_inits; +for (int i = 0; i < element_count; i++) { + all_inits += EXPECT_CALL(foo, InitElement(i)); +} +EXPECT_CALL(foo, Bar()) + .After(all_inits); +``` +says that `Bar()` can be called only after all elements have been +initialized (but we don't care about which elements get initialized +before the others). + +Modifying an `ExpectationSet` after using it in an `.After()` doesn't +affect the meaning of the `.After()`. + +## Sequences ## + +When you have a long chain of sequential expectations, it's easier to +specify the order using **sequences**, which don't require you to given +each expectation in the chain a different name. All expected
+calls in the same sequence must occur in the order they are +specified. + +``` +using ::testing::Sequence; +Sequence s1, s2; +... +EXPECT_CALL(foo, Reset()) + .InSequence(s1, s2) + .WillOnce(Return(true)); +EXPECT_CALL(foo, GetSize()) + .InSequence(s1) + .WillOnce(Return(1)); +EXPECT_CALL(foo, Describe(A())) + .InSequence(s2) + .WillOnce(Return("dummy")); +``` +says that `Reset()` must be called before _both_ `GetSize()` _and_ +`Describe()`, and the latter two can occur in any order. + +To put many expectations in a sequence conveniently: +``` +using ::testing::InSequence; +{ + InSequence dummy; + + EXPECT_CALL(...)...; + EXPECT_CALL(...)...; + ... + EXPECT_CALL(...)...; +} +``` +says that all expected calls in the scope of `dummy` must occur in +strict order. The name `dummy` is irrelevant.) + +# Verifying and Resetting a Mock # + +Google Mock will verify the expectations on a mock object when it is destructed, or you can do it earlier: +``` +using ::testing::Mock; +... +// Verifies and removes the expectations on mock_obj; +// returns true iff successful. +Mock::VerifyAndClearExpectations(&mock_obj); +... +// Verifies and removes the expectations on mock_obj; +// also removes the default actions set by ON_CALL(); +// returns true iff successful. +Mock::VerifyAndClear(&mock_obj); +``` + +You can also tell Google Mock that a mock object can be leaked and doesn't +need to be verified: +``` +Mock::AllowLeak(&mock_obj); +``` + +# Mock Classes # + +Google Mock defines a convenient mock class template +``` +class MockFunction { + public: + MOCK_METHODn(Call, R(A1, ..., An)); +}; +``` +See this [recipe](V1_5_CookBook#Using_Check_Points.md) for one application of it. + +# Flags # + +| `--gmock_catch_leaked_mocks=0` | Don't report leaked mock objects as failures. | +|:-------------------------------|:----------------------------------------------| +| `--gmock_verbose=LEVEL` | Sets the default verbosity level (`info`, `warning`, or `error`) of Google Mock messages. | \ No newline at end of file -- cgit v1.2.3