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diff --git a/tinyusb/test/vendor/ceedling/docs/UnityAssertionsReference.md b/tinyusb/test/vendor/ceedling/docs/UnityAssertionsReference.md new file mode 100755 index 00000000..eb855f3c --- /dev/null +++ b/tinyusb/test/vendor/ceedling/docs/UnityAssertionsReference.md @@ -0,0 +1,779 @@ +# Unity Assertions Reference + +## Background and Overview + +### Super Condensed Version + +- An assertion establishes truth (i.e. boolean True) for a single condition. +Upon boolean False, an assertion stops execution and reports the failure. +- Unity is mainly a rich collection of assertions and the support to gather up +and easily execute those assertions. +- The structure of Unity allows you to easily separate test assertions from +source code in, well, test code. +- Unity's assertions: +- Come in many, many flavors to handle different C types and assertion cases. +- Use context to provide detailed and helpful failure messages. +- Document types, expected values, and basic behavior in your source code for +free. + + +### Unity Is Several Things But Mainly It's Assertions + +One way to think of Unity is simply as a rich collection of assertions you can +use to establish whether your source code behaves the way you think it does. +Unity provides a framework to easily organize and execute those assertions in +test code separate from your source code. + + +### What's an Assertion? + +At their core, assertions are an establishment of truth - boolean truth. Was this +thing equal to that thing? Does that code doohickey have such-and-such property +or not? You get the idea. Assertions are executable code (to appreciate the big +picture on this read up on the difference between +[link:Dynamic Verification and Static Analysis]). A failing assertion stops +execution and reports an error through some appropriate I/O channel (e.g. +stdout, GUI, file, blinky light). + +Fundamentally, for dynamic verification all you need is a single assertion +mechanism. In fact, that's what the [assert() macro in C's standard library](http://en.wikipedia.org/en/wiki/Assert.h) +is for. So why not just use it? Well, we can do far better in the reporting +department. C's `assert()` is pretty dumb as-is and is particularly poor for +handling common data types like arrays, structs, etc. And, without some other +support, it's far too tempting to litter source code with C's `assert()`'s. It's +generally much cleaner, manageable, and more useful to separate test and source +code in the way Unity facilitates. + + +### Unity's Assertions: Helpful Messages _and_ Free Source Code Documentation + +Asserting a simple truth condition is valuable, but using the context of the +assertion is even more valuable. For instance, if you know you're comparing bit +flags and not just integers, then why not use that context to give explicit, +readable, bit-level feedback when an assertion fails? + +That's what Unity's collection of assertions do - capture context to give you +helpful, meaningful assertion failure messages. In fact, the assertions +themselves also serve as executable documentation about types and values in your +source code. So long as your tests remain current with your source and all those +tests pass, you have a detailed, up-to-date view of the intent and mechanisms in +your source code. And due to a wondrous mystery, well-tested code usually tends +to be well designed code. + + +## Assertion Conventions and Configurations + +### Naming and Parameter Conventions + +The convention of assertion parameters generally follows this order: + + TEST_ASSERT_X( {modifiers}, {expected}, actual, {size/count} ) + +The very simplest assertion possible uses only a single "actual" parameter (e.g. +a simple null check). + +"Actual" is the value being tested and unlike the other parameters in an +assertion construction is the only parameter present in all assertion variants. +"Modifiers" are masks, ranges, bit flag specifiers, floating point deltas. +"Expected" is your expected value (duh) to compare to an "actual" value; it's +marked as an optional parameter because some assertions only need a single +"actual" parameter (e.g. null check). +"Size/count" refers to string lengths, number of array elements, etc. + +Many of Unity's assertions are clear duplications in that the same data type +is handled by several assertions. The differences among these are in how failure +messages are presented. For instance, a `_HEX` variant of an assertion prints +the expected and actual values of that assertion formatted as hexadecimal. + + +#### TEST_ASSERT_X_MESSAGE Variants + +_All_ assertions are complemented with a variant that includes a simple string +message as a final parameter. The string you specify is appended to an assertion +failure message in Unity output. + +For brevity, the assertion variants with a message parameter are not listed +below. Just tack on `_MESSAGE` as the final component to any assertion name in +the reference list below and add a string as the final parameter. + +_Example:_ + + TEST_ASSERT_X( {modifiers}, {expected}, actual, {size/count} ) + +becomes messageified like thus... + + TEST_ASSERT_X_MESSAGE( {modifiers}, {expected}, actual, {size/count}, message ) + +Notes: +- The `_MESSAGE` variants intentionally do not support `printf` style formatting + since many embedded projects don't support or avoid `printf` for various reasons. + It is possible to use `sprintf` before the assertion to assemble a complex fail + message, if necessary. +- If you want to output a counter value within an assertion fail message (e.g. from + a loop) , building up an array of results and then using one of the `_ARRAY` + assertions (see below) might be a handy alternative to `sprintf`. + + +#### TEST_ASSERT_X_ARRAY Variants + +Unity provides a collection of assertions for arrays containing a variety of +types. These are documented in the Array section below. These are almost on par +with the `_MESSAGE`variants of Unity's Asserts in that for pretty much any Unity +type assertion you can tack on `_ARRAY` and run assertions on an entire block of +memory. + + TEST_ASSERT_EQUAL_TYPEX_ARRAY( expected, actual, {size/count} ) + +"Expected" is an array itself. +"Size/count" is one or two parameters necessary to establish the number of array +elements and perhaps the length of elements within the array. + +Notes: +- The `_MESSAGE` variant convention still applies here to array assertions. The +`_MESSAGE` variants of the `_ARRAY` assertions have names ending with +`_ARRAY_MESSAGE`. +- Assertions for handling arrays of floating point values are grouped with float +and double assertions (see immediately following section). + + +### TEST_ASSERT_EACH_EQUAL_X Variants + +Unity provides a collection of assertions for arrays containing a variety of +types which can be compared to a single value as well. These are documented in +the Each Equal section below. these are almost on par with the `_MESSAGE` +variants of Unity's Asserts in that for pretty much any Unity type assertion you +can inject _EACH_EQUAL and run assertions on an entire block of memory. + + TEST_ASSERT_EACH_EQUAL_TYPEX( expected, actual, {size/count} ) + +"Expected" is a single value to compare to. +"Actual" is an array where each element will be compared to the expected value. +"Size/count" is one of two parameters necessary to establish the number of array +elements and perhaps the length of elements within the array. + +Notes: +- The `_MESSAGE` variant convention still applies here to Each Equal assertions. +- Assertions for handling Each Equal of floating point values are grouped with +float and double assertions (see immediately following section). + + +### Configuration + +#### Floating Point Support Is Optional + +Support for floating point types is configurable. That is, by defining the +appropriate preprocessor symbols, floats and doubles can be individually enabled +or disabled in Unity code. This is useful for embedded targets with no floating +point math support (i.e. Unity compiles free of errors for fixed point only +platforms). See Unity documentation for specifics. + + +#### Maximum Data Type Width Is Configurable + +Not all targets support 64 bit wide types or even 32 bit wide types. Define the +appropriate preprocessor symbols and Unity will omit all operations from +compilation that exceed the maximum width of your target. See Unity +documentation for specifics. + + +## The Assertions in All Their Blessed Glory + +### Basic Fail and Ignore + +##### `TEST_FAIL()` + +This fella is most often used in special conditions where your test code is +performing logic beyond a simple assertion. That is, in practice, `TEST_FAIL()` +will always be found inside a conditional code block. + +_Examples:_ +- Executing a state machine multiple times that increments a counter your test +code then verifies as a final step. +- Triggering an exception and verifying it (as in Try / Catch / Throw - see the +[CException](https://github.com/ThrowTheSwitch/CException) project). + +##### `TEST_IGNORE()` + +Marks a test case (i.e. function meant to contain test assertions) as ignored. +Usually this is employed as a breadcrumb to come back and implement a test case. +An ignored test case has effects if other assertions are in the enclosing test +case (see Unity documentation for more). + +### Boolean + +##### `TEST_ASSERT (condition)` + +##### `TEST_ASSERT_TRUE (condition)` + +##### `TEST_ASSERT_FALSE (condition)` + +##### `TEST_ASSERT_UNLESS (condition)` + +A simple wording variation on `TEST_ASSERT_FALSE`.The semantics of +`TEST_ASSERT_UNLESS` aid readability in certain test constructions or +conditional statements. + +##### `TEST_ASSERT_NULL (pointer)` + +##### `TEST_ASSERT_NOT_NULL (pointer)` + + +### Signed and Unsigned Integers (of all sizes) + +Large integer sizes can be disabled for build targets that do not support them. +For example, if your target only supports up to 16 bit types, by defining the +appropriate symbols Unity can be configured to omit 32 and 64 bit operations +that would break compilation (see Unity documentation for more). Refer to +Advanced Asserting later in this document for advice on dealing with other word +sizes. + +##### `TEST_ASSERT_EQUAL_INT (expected, actual)` + +##### `TEST_ASSERT_EQUAL_INT8 (expected, actual)` + +##### `TEST_ASSERT_EQUAL_INT16 (expected, actual)` + +##### `TEST_ASSERT_EQUAL_INT32 (expected, actual)` + +##### `TEST_ASSERT_EQUAL_INT64 (expected, actual)` + +##### `TEST_ASSERT_EQUAL (expected, actual)` + +##### `TEST_ASSERT_NOT_EQUAL (expected, actual)` + +##### `TEST_ASSERT_EQUAL_UINT (expected, actual)` + +##### `TEST_ASSERT_EQUAL_UINT8 (expected, actual)` + +##### `TEST_ASSERT_EQUAL_UINT16 (expected, actual)` + +##### `TEST_ASSERT_EQUAL_UINT32 (expected, actual)` + +##### `TEST_ASSERT_EQUAL_UINT64 (expected, actual)` + + +### Unsigned Integers (of all sizes) in Hexadecimal + +All `_HEX` assertions are identical in function to unsigned integer assertions +but produce failure messages with the `expected` and `actual` values formatted +in hexadecimal. Unity output is big endian. + +##### `TEST_ASSERT_EQUAL_HEX (expected, actual)` + +##### `TEST_ASSERT_EQUAL_HEX8 (expected, actual)` + +##### `TEST_ASSERT_EQUAL_HEX16 (expected, actual)` + +##### `TEST_ASSERT_EQUAL_HEX32 (expected, actual)` + +##### `TEST_ASSERT_EQUAL_HEX64 (expected, actual)` + + +### Masked and Bit-level Assertions + +Masked and bit-level assertions produce output formatted in hexadecimal. Unity +output is big endian. + + +##### `TEST_ASSERT_BITS (mask, expected, actual)` + +Only compares the masked (i.e. high) bits of `expected` and `actual` parameters. + + +##### `TEST_ASSERT_BITS_HIGH (mask, actual)` + +Asserts the masked bits of the `actual` parameter are high. + + +##### `TEST_ASSERT_BITS_LOW (mask, actual)` + +Asserts the masked bits of the `actual` parameter are low. + + +##### `TEST_ASSERT_BIT_HIGH (bit, actual)` + +Asserts the specified bit of the `actual` parameter is high. + + +##### `TEST_ASSERT_BIT_LOW (bit, actual)` + +Asserts the specified bit of the `actual` parameter is low. + +### Integer Less Than / Greater Than + +These assertions verify that the `actual` parameter is less than or greater +than `threshold` (exclusive). For example, if the threshold value is 0 for the +greater than assertion will fail if it is 0 or less. + +##### `TEST_ASSERT_GREATER_THAN (threshold, actual)` + +##### `TEST_ASSERT_GREATER_THAN_INT (threshold, actual)` + +##### `TEST_ASSERT_GREATER_THAN_INT8 (threshold, actual)` + +##### `TEST_ASSERT_GREATER_THAN_INT16 (threshold, actual)` + +##### `TEST_ASSERT_GREATER_THAN_INT32 (threshold, actual)` + +##### `TEST_ASSERT_GREATER_THAN_UINT (threshold, actual)` + +##### `TEST_ASSERT_GREATER_THAN_UINT8 (threshold, actual)` + +##### `TEST_ASSERT_GREATER_THAN_UINT16 (threshold, actual)` + +##### `TEST_ASSERT_GREATER_THAN_UINT32 (threshold, actual)` + +##### `TEST_ASSERT_GREATER_THAN_HEX8 (threshold, actual)` + +##### `TEST_ASSERT_GREATER_THAN_HEX16 (threshold, actual)` + +##### `TEST_ASSERT_GREATER_THAN_HEX32 (threshold, actual)` + +##### `TEST_ASSERT_LESS_THAN (threshold, actual)` + +##### `TEST_ASSERT_LESS_THAN_INT (threshold, actual)` + +##### `TEST_ASSERT_LESS_THAN_INT8 (threshold, actual)` + +##### `TEST_ASSERT_LESS_THAN_INT16 (threshold, actual)` + +##### `TEST_ASSERT_LESS_THAN_INT32 (threshold, actual)` + +##### `TEST_ASSERT_LESS_THAN_UINT (threshold, actual)` + +##### `TEST_ASSERT_LESS_THAN_UINT8 (threshold, actual)` + +##### `TEST_ASSERT_LESS_THAN_UINT16 (threshold, actual)` + +##### `TEST_ASSERT_LESS_THAN_UINT32 (threshold, actual)` + +##### `TEST_ASSERT_LESS_THAN_HEX8 (threshold, actual)` + +##### `TEST_ASSERT_LESS_THAN_HEX16 (threshold, actual)` + +##### `TEST_ASSERT_LESS_THAN_HEX32 (threshold, actual)` + + +### Integer Ranges (of all sizes) + +These assertions verify that the `expected` parameter is within +/- `delta` +(inclusive) of the `actual` parameter. For example, if the expected value is 10 +and the delta is 3 then the assertion will fail for any value outside the range +of 7 - 13. + +##### `TEST_ASSERT_INT_WITHIN (delta, expected, actual)` + +##### `TEST_ASSERT_INT8_WITHIN (delta, expected, actual)` + +##### `TEST_ASSERT_INT16_WITHIN (delta, expected, actual)` + +##### `TEST_ASSERT_INT32_WITHIN (delta, expected, actual)` + +##### `TEST_ASSERT_INT64_WITHIN (delta, expected, actual)` + +##### `TEST_ASSERT_UINT_WITHIN (delta, expected, actual)` + +##### `TEST_ASSERT_UINT8_WITHIN (delta, expected, actual)` + +##### `TEST_ASSERT_UINT16_WITHIN (delta, expected, actual)` + +##### `TEST_ASSERT_UINT32_WITHIN (delta, expected, actual)` + +##### `TEST_ASSERT_UINT64_WITHIN (delta, expected, actual)` + +##### `TEST_ASSERT_HEX_WITHIN (delta, expected, actual)` + +##### `TEST_ASSERT_HEX8_WITHIN (delta, expected, actual)` + +##### `TEST_ASSERT_HEX16_WITHIN (delta, expected, actual)` + +##### `TEST_ASSERT_HEX32_WITHIN (delta, expected, actual)` + +##### `TEST_ASSERT_HEX64_WITHIN (delta, expected, actual)` + + +### Structs and Strings + +##### `TEST_ASSERT_EQUAL_PTR (expected, actual)` + +Asserts that the pointers point to the same memory location. + + +##### `TEST_ASSERT_EQUAL_STRING (expected, actual)` + +Asserts that the null terminated (`'\0'`)strings are identical. If strings are +of different lengths or any portion of the strings before their terminators +differ, the assertion fails. Two NULL strings (i.e. zero length) are considered +equivalent. + + +##### `TEST_ASSERT_EQUAL_MEMORY (expected, actual, len)` + +Asserts that the contents of the memory specified by the `expected` and `actual` +pointers is identical. The size of the memory blocks in bytes is specified by +the `len` parameter. + + +### Arrays + +`expected` and `actual` parameters are both arrays. `num_elements` specifies the +number of elements in the arrays to compare. + +`_HEX` assertions produce failure messages with expected and actual array +contents formatted in hexadecimal. + +For array of strings comparison behavior, see comments for +`TEST_ASSERT_EQUAL_STRING` in the preceding section. + +Assertions fail upon the first element in the compared arrays found not to +match. Failure messages specify the array index of the failed comparison. + +##### `TEST_ASSERT_EQUAL_INT_ARRAY (expected, actual, num_elements)` + +##### `TEST_ASSERT_EQUAL_INT8_ARRAY (expected, actual, num_elements)` + +##### `TEST_ASSERT_EQUAL_INT16_ARRAY (expected, actual, num_elements)` + +##### `TEST_ASSERT_EQUAL_INT32_ARRAY (expected, actual, num_elements)` + +##### `TEST_ASSERT_EQUAL_INT64_ARRAY (expected, actual, num_elements)` + +##### `TEST_ASSERT_EQUAL_UINT_ARRAY (expected, actual, num_elements)` + +##### `TEST_ASSERT_EQUAL_UINT8_ARRAY (expected, actual, num_elements)` + +##### `TEST_ASSERT_EQUAL_UINT16_ARRAY (expected, actual, num_elements)` + +##### `TEST_ASSERT_EQUAL_UINT32_ARRAY (expected, actual, num_elements)` + +##### `TEST_ASSERT_EQUAL_UINT64_ARRAY (expected, actual, num_elements)` + +##### `TEST_ASSERT_EQUAL_HEX_ARRAY (expected, actual, num_elements)` + +##### `TEST_ASSERT_EQUAL_HEX8_ARRAY (expected, actual, num_elements)` + +##### `TEST_ASSERT_EQUAL_HEX16_ARRAY (expected, actual, num_elements)` + +##### `TEST_ASSERT_EQUAL_HEX32_ARRAY (expected, actual, num_elements)` + +##### `TEST_ASSERT_EQUAL_HEX64_ARRAY (expected, actual, num_elements)` + +##### `TEST_ASSERT_EQUAL_PTR_ARRAY (expected, actual, num_elements)` + +##### `TEST_ASSERT_EQUAL_STRING_ARRAY (expected, actual, num_elements)` + +##### `TEST_ASSERT_EQUAL_MEMORY_ARRAY (expected, actual, len, num_elements)` + +`len` is the memory in bytes to be compared at each array element. + + +### Each Equal (Arrays to Single Value) + +`expected` are single values and `actual` are arrays. `num_elements` specifies +the number of elements in the arrays to compare. + +`_HEX` assertions produce failure messages with expected and actual array +contents formatted in hexadecimal. + +Assertions fail upon the first element in the compared arrays found not to +match. Failure messages specify the array index of the failed comparison. + +#### `TEST_ASSERT_EACH_EQUAL_INT (expected, actual, num_elements)` + +#### `TEST_ASSERT_EACH_EQUAL_INT8 (expected, actual, num_elements)` + +#### `TEST_ASSERT_EACH_EQUAL_INT16 (expected, actual, num_elements)` + +#### `TEST_ASSERT_EACH_EQUAL_INT32 (expected, actual, num_elements)` + +#### `TEST_ASSERT_EACH_EQUAL_INT64 (expected, actual, num_elements)` + +#### `TEST_ASSERT_EACH_EQUAL_UINT (expected, actual, num_elements)` + +#### `TEST_ASSERT_EACH_EQUAL_UINT8 (expected, actual, num_elements)` + +#### `TEST_ASSERT_EACH_EQUAL_UINT16 (expected, actual, num_elements)` + +#### `TEST_ASSERT_EACH_EQUAL_UINT32 (expected, actual, num_elements)` + +#### `TEST_ASSERT_EACH_EQUAL_UINT64 (expected, actual, num_elements)` + +#### `TEST_ASSERT_EACH_EQUAL_HEX (expected, actual, num_elements)` + +#### `TEST_ASSERT_EACH_EQUAL_HEX8 (expected, actual, num_elements)` + +#### `TEST_ASSERT_EACH_EQUAL_HEX16 (expected, actual, num_elements)` + +#### `TEST_ASSERT_EACH_EQUAL_HEX32 (expected, actual, num_elements)` + +#### `TEST_ASSERT_EACH_EQUAL_HEX64 (expected, actual, num_elements)` + +#### `TEST_ASSERT_EACH_EQUAL_PTR (expected, actual, num_elements)` + +#### `TEST_ASSERT_EACH_EQUAL_STRING (expected, actual, num_elements)` + +#### `TEST_ASSERT_EACH_EQUAL_MEMORY (expected, actual, len, num_elements)` + +`len` is the memory in bytes to be compared at each array element. + + +### Floating Point (If enabled) + +##### `TEST_ASSERT_FLOAT_WITHIN (delta, expected, actual)` + +Asserts that the `actual` value is within +/- `delta` of the `expected` value. +The nature of floating point representation is such that exact evaluations of +equality are not guaranteed. + + +##### `TEST_ASSERT_EQUAL_FLOAT (expected, actual)` + +Asserts that the ?actual?value is "close enough to be considered equal" to the +`expected` value. If you are curious about the details, refer to the Advanced +Asserting section for more details on this. Omitting a user-specified delta in a +floating point assertion is both a shorthand convenience and a requirement of +code generation conventions for CMock. + + +##### `TEST_ASSERT_EQUAL_FLOAT_ARRAY (expected, actual, num_elements)` + +See Array assertion section for details. Note that individual array element +float comparisons are executed using T?EST_ASSERT_EQUAL_FLOAT?.That is, user +specified delta comparison values requires a custom-implemented floating point +array assertion. + + +##### `TEST_ASSERT_FLOAT_IS_INF (actual)` + +Asserts that `actual` parameter is equivalent to positive infinity floating +point representation. + + +##### `TEST_ASSERT_FLOAT_IS_NEG_INF (actual)` + +Asserts that `actual` parameter is equivalent to negative infinity floating +point representation. + + +##### `TEST_ASSERT_FLOAT_IS_NAN (actual)` + +Asserts that `actual` parameter is a Not A Number floating point representation. + + +##### `TEST_ASSERT_FLOAT_IS_DETERMINATE (actual)` + +Asserts that ?actual?parameter is a floating point representation usable for +mathematical operations. That is, the `actual` parameter is neither positive +infinity nor negative infinity nor Not A Number floating point representations. + + +##### `TEST_ASSERT_FLOAT_IS_NOT_INF (actual)` + +Asserts that `actual` parameter is a value other than positive infinity floating +point representation. + + +##### `TEST_ASSERT_FLOAT_IS_NOT_NEG_INF (actual)` + +Asserts that `actual` parameter is a value other than negative infinity floating +point representation. + + +##### `TEST_ASSERT_FLOAT_IS_NOT_NAN (actual)` + +Asserts that `actual` parameter is a value other than Not A Number floating +point representation. + + +##### `TEST_ASSERT_FLOAT_IS_NOT_DETERMINATE (actual)` + +Asserts that `actual` parameter is not usable for mathematical operations. That +is, the `actual` parameter is either positive infinity or negative infinity or +Not A Number floating point representations. + + +### Double (If enabled) + +##### `TEST_ASSERT_DOUBLE_WITHIN (delta, expected, actual)` + +Asserts that the `actual` value is within +/- `delta` of the `expected` value. +The nature of floating point representation is such that exact evaluations of +equality are not guaranteed. + + +##### `TEST_ASSERT_EQUAL_DOUBLE (expected, actual)` + +Asserts that the `actual` value is "close enough to be considered equal" to the +`expected` value. If you are curious about the details, refer to the Advanced +Asserting section for more details. Omitting a user-specified delta in a +floating point assertion is both a shorthand convenience and a requirement of +code generation conventions for CMock. + + +##### `TEST_ASSERT_EQUAL_DOUBLE_ARRAY (expected, actual, num_elements)` + +See Array assertion section for details. Note that individual array element +double comparisons are executed using `TEST_ASSERT_EQUAL_DOUBLE`.That is, user +specified delta comparison values requires a custom implemented double array +assertion. + + +##### `TEST_ASSERT_DOUBLE_IS_INF (actual)` + +Asserts that `actual` parameter is equivalent to positive infinity floating +point representation. + + +##### `TEST_ASSERT_DOUBLE_IS_NEG_INF (actual)` + +Asserts that `actual` parameter is equivalent to negative infinity floating point +representation. + + +##### `TEST_ASSERT_DOUBLE_IS_NAN (actual)` + +Asserts that `actual` parameter is a Not A Number floating point representation. + + +##### `TEST_ASSERT_DOUBLE_IS_DETERMINATE (actual)` + +Asserts that `actual` parameter is a floating point representation usable for +mathematical operations. That is, the ?actual?parameter is neither positive +infinity nor negative infinity nor Not A Number floating point representations. + + +##### `TEST_ASSERT_DOUBLE_IS_NOT_INF (actual)` + +Asserts that `actual` parameter is a value other than positive infinity floating +point representation. + + +##### `TEST_ASSERT_DOUBLE_IS_NOT_NEG_INF (actual)` + +Asserts that `actual` parameter is a value other than negative infinity floating +point representation. + + +##### `TEST_ASSERT_DOUBLE_IS_NOT_NAN (actual)` + +Asserts that `actual` parameter is a value other than Not A Number floating +point representation. + + +##### `TEST_ASSERT_DOUBLE_IS_NOT_DETERMINATE (actual)` + +Asserts that `actual` parameter is not usable for mathematical operations. That +is, the `actual` parameter is either positive infinity or negative infinity or +Not A Number floating point representations. + + +## Advanced Asserting: Details On Tricky Assertions + +This section helps you understand how to deal with some of the trickier +assertion situations you may run into. It will give you a glimpse into some of +the under-the-hood details of Unity's assertion mechanisms. If you're one of +those people who likes to know what is going on in the background, read on. If +not, feel free to ignore the rest of this document until you need it. + + +### How do the EQUAL assertions work for FLOAT and DOUBLE? + +As you may know, directly checking for equality between a pair of floats or a +pair of doubles is sloppy at best and an outright no-no at worst. Floating point +values can often be represented in multiple ways, particularly after a series of +operations on a value. Initializing a variable to the value of 2.0 is likely to +result in a floating point representation of 2 x 20,but a series of +mathematical operations might result in a representation of 8 x 2-2 +that also evaluates to a value of 2. At some point repeated operations cause +equality checks to fail. + +So Unity doesn't do direct floating point comparisons for equality. Instead, it +checks if two floating point values are "really close." If you leave Unity +running with defaults, "really close" means "within a significant bit or two." +Under the hood, `TEST_ASSERT_EQUAL_FLOAT` is really `TEST_ASSERT_FLOAT_WITHIN` +with the `delta` parameter calculated on the fly. For single precision, delta is +the expected value multiplied by 0.00001, producing a very small proportional +range around the expected value. + +If you are expecting a value of 20,000.0 the delta is calculated to be 0.2. So +any value between 19,999.8 and 20,000.2 will satisfy the equality check. This +works out to be roughly a single bit of range for a single-precision number, and +that's just about as tight a tolerance as you can reasonably get from a floating +point value. + +So what happens when it's zero? Zero - even more than other floating point +values - can be represented many different ways. It doesn't matter if you have +0 x 20 or 0 x 263.It's still zero, right? Luckily, if you +subtract these values from each other, they will always produce a difference of +zero, which will still fall between 0 plus or minus a delta of 0. So it still +works! + +Double precision floating point numbers use a much smaller multiplier, again +approximating a single bit of error. + +If you don't like these ranges and you want to make your floating point equality +assertions less strict, you can change these multipliers to whatever you like by +defining UNITY_FLOAT_PRECISION and UNITY_DOUBLE_PRECISION. See Unity +documentation for more. + + +### How do we deal with targets with non-standard int sizes? + +It's "fun" that C is a standard where something as fundamental as an integer +varies by target. According to the C standard, an `int` is to be the target's +natural register size, and it should be at least 16-bits and a multiple of a +byte. It also guarantees an order of sizes: + +```C +char <= short <= int <= long <= long long +``` + +Most often, `int` is 32-bits. In many cases in the embedded world, `int` is +16-bits. There are rare microcontrollers out there that have 24-bit integers, +and this remains perfectly standard C. + +To make things even more interesting, there are compilers and targets out there +that have a hard choice to make. What if their natural register size is 10-bits +or 12-bits? Clearly they can't fulfill _both_ the requirement to be at least +16-bits AND the requirement to match the natural register size. In these +situations, they often choose the natural register size, leaving us with +something like this: + +```C +char (8 bit) <= short (12 bit) <= int (12 bit) <= long (16 bit) +``` + +Um... yikes. It's obviously breaking a rule or two... but they had to break SOME +rules, so they made a choice. + +When the C99 standard rolled around, it introduced alternate standard-size types. +It also introduced macros for pulling in MIN/MAX values for your integer types. +It's glorious! Unfortunately, many embedded compilers can't be relied upon to +use the C99 types (Sometimes because they have weird register sizes as described +above. Sometimes because they don't feel like it?). + +A goal of Unity from the beginning was to support every combination of +microcontroller or microprocessor and C compiler. Over time, we've gotten really +close to this. There are a few tricks that you should be aware of, though, if +you're going to do this effectively on some of these more idiosyncratic targets. + +First, when setting up Unity for a new target, you're going to want to pay +special attention to the macros for automatically detecting types +(where available) or manually configuring them yourself. You can get information +on both of these in Unity's documentation. + +What about the times where you suddenly need to deal with something odd, like a +24-bit `int`? The simplest solution is to use the next size up. If you have a +24-bit `int`, configure Unity to use 32-bit integers. If you have a 12-bit +`int`, configure Unity to use 16 bits. There are two ways this is going to +affect you: + +1. When Unity displays errors for you, it's going to pad the upper unused bits +with zeros. +2. You're going to have to be careful of assertions that perform signed +operations, particularly `TEST_ASSERT_INT_WITHIN`.Such assertions might wrap +your `int` in the wrong place, and you could experience false failures. You can +always back down to a simple `TEST_ASSERT` and do the operations yourself. + + +*Find The Latest of This And More at [ThrowTheSwitch.org](https://throwtheswitch.org)* |