780 lines
28 KiB
Markdown
780 lines
28 KiB
Markdown
# Unity Assertions Reference
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## Background and Overview
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### Super Condensed Version
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- An assertion establishes truth (i.e. boolean True) for a single condition.
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Upon boolean False, an assertion stops execution and reports the failure.
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- Unity is mainly a rich collection of assertions and the support to gather up
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and easily execute those assertions.
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- The structure of Unity allows you to easily separate test assertions from
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source code in, well, test code.
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- Unity's assertions:
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- Come in many, many flavors to handle different C types and assertion cases.
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- Use context to provide detailed and helpful failure messages.
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- Document types, expected values, and basic behavior in your source code for
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free.
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### Unity Is Several Things But Mainly It's Assertions
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One way to think of Unity is simply as a rich collection of assertions you can
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use to establish whether your source code behaves the way you think it does.
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Unity provides a framework to easily organize and execute those assertions in
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test code separate from your source code.
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### What's an Assertion?
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At their core, assertions are an establishment of truth - boolean truth. Was this
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thing equal to that thing? Does that code doohickey have such-and-such property
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or not? You get the idea. Assertions are executable code (to appreciate the big
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picture on this read up on the difference between
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[link:Dynamic Verification and Static Analysis]). A failing assertion stops
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execution and reports an error through some appropriate I/O channel (e.g.
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stdout, GUI, file, blinky light).
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Fundamentally, for dynamic verification all you need is a single assertion
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mechanism. In fact, that's what the [assert() macro in C's standard library](http://en.wikipedia.org/en/wiki/Assert.h)
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is for. So why not just use it? Well, we can do far better in the reporting
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department. C's `assert()` is pretty dumb as-is and is particularly poor for
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handling common data types like arrays, structs, etc. And, without some other
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support, it's far too tempting to litter source code with C's `assert()`'s. It's
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generally much cleaner, manageable, and more useful to separate test and source
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code in the way Unity facilitates.
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### Unity's Assertions: Helpful Messages _and_ Free Source Code Documentation
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Asserting a simple truth condition is valuable, but using the context of the
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assertion is even more valuable. For instance, if you know you're comparing bit
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flags and not just integers, then why not use that context to give explicit,
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readable, bit-level feedback when an assertion fails?
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That's what Unity's collection of assertions do - capture context to give you
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helpful, meaningful assertion failure messages. In fact, the assertions
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themselves also serve as executable documentation about types and values in your
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source code. So long as your tests remain current with your source and all those
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tests pass, you have a detailed, up-to-date view of the intent and mechanisms in
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your source code. And due to a wondrous mystery, well-tested code usually tends
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to be well designed code.
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## Assertion Conventions and Configurations
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### Naming and Parameter Conventions
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The convention of assertion parameters generally follows this order:
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TEST_ASSERT_X( {modifiers}, {expected}, actual, {size/count} )
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The very simplest assertion possible uses only a single "actual" parameter (e.g.
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a simple null check).
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"Actual" is the value being tested and unlike the other parameters in an
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assertion construction is the only parameter present in all assertion variants.
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"Modifiers" are masks, ranges, bit flag specifiers, floating point deltas.
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"Expected" is your expected value (duh) to compare to an "actual" value; it's
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marked as an optional parameter because some assertions only need a single
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"actual" parameter (e.g. null check).
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"Size/count" refers to string lengths, number of array elements, etc.
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Many of Unity's assertions are clear duplications in that the same data type
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is handled by several assertions. The differences among these are in how failure
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messages are presented. For instance, a `_HEX` variant of an assertion prints
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the expected and actual values of that assertion formatted as hexadecimal.
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#### TEST_ASSERT_X_MESSAGE Variants
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_All_ assertions are complemented with a variant that includes a simple string
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message as a final parameter. The string you specify is appended to an assertion
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failure message in Unity output.
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For brevity, the assertion variants with a message parameter are not listed
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below. Just tack on `_MESSAGE` as the final component to any assertion name in
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the reference list below and add a string as the final parameter.
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_Example:_
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TEST_ASSERT_X( {modifiers}, {expected}, actual, {size/count} )
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becomes messageified like thus...
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TEST_ASSERT_X_MESSAGE( {modifiers}, {expected}, actual, {size/count}, message )
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Notes:
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- The `_MESSAGE` variants intentionally do not support `printf` style formatting
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since many embedded projects don't support or avoid `printf` for various reasons.
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It is possible to use `sprintf` before the assertion to assemble a complex fail
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message, if necessary.
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- If you want to output a counter value within an assertion fail message (e.g. from
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a loop) , building up an array of results and then using one of the `_ARRAY`
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assertions (see below) might be a handy alternative to `sprintf`.
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#### TEST_ASSERT_X_ARRAY Variants
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Unity provides a collection of assertions for arrays containing a variety of
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types. These are documented in the Array section below. These are almost on par
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with the `_MESSAGE`variants of Unity's Asserts in that for pretty much any Unity
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type assertion you can tack on `_ARRAY` and run assertions on an entire block of
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memory.
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TEST_ASSERT_EQUAL_TYPEX_ARRAY( expected, actual, {size/count} )
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"Expected" is an array itself.
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"Size/count" is one or two parameters necessary to establish the number of array
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elements and perhaps the length of elements within the array.
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Notes:
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- The `_MESSAGE` variant convention still applies here to array assertions. The
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`_MESSAGE` variants of the `_ARRAY` assertions have names ending with
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`_ARRAY_MESSAGE`.
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- Assertions for handling arrays of floating point values are grouped with float
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and double assertions (see immediately following section).
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### TEST_ASSERT_EACH_EQUAL_X Variants
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Unity provides a collection of assertions for arrays containing a variety of
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types which can be compared to a single value as well. These are documented in
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the Each Equal section below. these are almost on par with the `_MESSAGE`
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variants of Unity's Asserts in that for pretty much any Unity type assertion you
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can inject _EACH_EQUAL and run assertions on an entire block of memory.
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TEST_ASSERT_EACH_EQUAL_TYPEX( expected, actual, {size/count} )
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"Expected" is a single value to compare to.
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"Actual" is an array where each element will be compared to the expected value.
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"Size/count" is one of two parameters necessary to establish the number of array
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elements and perhaps the length of elements within the array.
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Notes:
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- The `_MESSAGE` variant convention still applies here to Each Equal assertions.
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- Assertions for handling Each Equal of floating point values are grouped with
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float and double assertions (see immediately following section).
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### Configuration
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#### Floating Point Support Is Optional
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Support for floating point types is configurable. That is, by defining the
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appropriate preprocessor symbols, floats and doubles can be individually enabled
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or disabled in Unity code. This is useful for embedded targets with no floating
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point math support (i.e. Unity compiles free of errors for fixed point only
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platforms). See Unity documentation for specifics.
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#### Maximum Data Type Width Is Configurable
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Not all targets support 64 bit wide types or even 32 bit wide types. Define the
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appropriate preprocessor symbols and Unity will omit all operations from
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compilation that exceed the maximum width of your target. See Unity
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documentation for specifics.
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## The Assertions in All Their Blessed Glory
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### Basic Fail and Ignore
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##### `TEST_FAIL()`
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This fella is most often used in special conditions where your test code is
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performing logic beyond a simple assertion. That is, in practice, `TEST_FAIL()`
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will always be found inside a conditional code block.
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_Examples:_
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- Executing a state machine multiple times that increments a counter your test
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code then verifies as a final step.
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- Triggering an exception and verifying it (as in Try / Catch / Throw - see the
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[CException](https://github.com/ThrowTheSwitch/CException) project).
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##### `TEST_IGNORE()`
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Marks a test case (i.e. function meant to contain test assertions) as ignored.
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Usually this is employed as a breadcrumb to come back and implement a test case.
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An ignored test case has effects if other assertions are in the enclosing test
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case (see Unity documentation for more).
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### Boolean
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##### `TEST_ASSERT (condition)`
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##### `TEST_ASSERT_TRUE (condition)`
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##### `TEST_ASSERT_FALSE (condition)`
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##### `TEST_ASSERT_UNLESS (condition)`
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A simple wording variation on `TEST_ASSERT_FALSE`.The semantics of
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`TEST_ASSERT_UNLESS` aid readability in certain test constructions or
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conditional statements.
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##### `TEST_ASSERT_NULL (pointer)`
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##### `TEST_ASSERT_NOT_NULL (pointer)`
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### Signed and Unsigned Integers (of all sizes)
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Large integer sizes can be disabled for build targets that do not support them.
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For example, if your target only supports up to 16 bit types, by defining the
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appropriate symbols Unity can be configured to omit 32 and 64 bit operations
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that would break compilation (see Unity documentation for more). Refer to
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Advanced Asserting later in this document for advice on dealing with other word
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sizes.
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##### `TEST_ASSERT_EQUAL_INT (expected, actual)`
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##### `TEST_ASSERT_EQUAL_INT8 (expected, actual)`
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##### `TEST_ASSERT_EQUAL_INT16 (expected, actual)`
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##### `TEST_ASSERT_EQUAL_INT32 (expected, actual)`
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##### `TEST_ASSERT_EQUAL_INT64 (expected, actual)`
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##### `TEST_ASSERT_EQUAL (expected, actual)`
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##### `TEST_ASSERT_NOT_EQUAL (expected, actual)`
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##### `TEST_ASSERT_EQUAL_UINT (expected, actual)`
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##### `TEST_ASSERT_EQUAL_UINT8 (expected, actual)`
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##### `TEST_ASSERT_EQUAL_UINT16 (expected, actual)`
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##### `TEST_ASSERT_EQUAL_UINT32 (expected, actual)`
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##### `TEST_ASSERT_EQUAL_UINT64 (expected, actual)`
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### Unsigned Integers (of all sizes) in Hexadecimal
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All `_HEX` assertions are identical in function to unsigned integer assertions
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but produce failure messages with the `expected` and `actual` values formatted
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in hexadecimal. Unity output is big endian.
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##### `TEST_ASSERT_EQUAL_HEX (expected, actual)`
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##### `TEST_ASSERT_EQUAL_HEX8 (expected, actual)`
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##### `TEST_ASSERT_EQUAL_HEX16 (expected, actual)`
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##### `TEST_ASSERT_EQUAL_HEX32 (expected, actual)`
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##### `TEST_ASSERT_EQUAL_HEX64 (expected, actual)`
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### Masked and Bit-level Assertions
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Masked and bit-level assertions produce output formatted in hexadecimal. Unity
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output is big endian.
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##### `TEST_ASSERT_BITS (mask, expected, actual)`
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Only compares the masked (i.e. high) bits of `expected` and `actual` parameters.
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##### `TEST_ASSERT_BITS_HIGH (mask, actual)`
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Asserts the masked bits of the `actual` parameter are high.
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##### `TEST_ASSERT_BITS_LOW (mask, actual)`
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Asserts the masked bits of the `actual` parameter are low.
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##### `TEST_ASSERT_BIT_HIGH (bit, actual)`
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Asserts the specified bit of the `actual` parameter is high.
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##### `TEST_ASSERT_BIT_LOW (bit, actual)`
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Asserts the specified bit of the `actual` parameter is low.
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### Integer Less Than / Greater Than
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These assertions verify that the `actual` parameter is less than or greater
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than `threshold` (exclusive). For example, if the threshold value is 0 for the
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greater than assertion will fail if it is 0 or less.
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##### `TEST_ASSERT_GREATER_THAN (threshold, actual)`
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##### `TEST_ASSERT_GREATER_THAN_INT (threshold, actual)`
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##### `TEST_ASSERT_GREATER_THAN_INT8 (threshold, actual)`
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##### `TEST_ASSERT_GREATER_THAN_INT16 (threshold, actual)`
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##### `TEST_ASSERT_GREATER_THAN_INT32 (threshold, actual)`
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##### `TEST_ASSERT_GREATER_THAN_UINT (threshold, actual)`
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##### `TEST_ASSERT_GREATER_THAN_UINT8 (threshold, actual)`
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##### `TEST_ASSERT_GREATER_THAN_UINT16 (threshold, actual)`
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##### `TEST_ASSERT_GREATER_THAN_UINT32 (threshold, actual)`
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##### `TEST_ASSERT_GREATER_THAN_HEX8 (threshold, actual)`
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##### `TEST_ASSERT_GREATER_THAN_HEX16 (threshold, actual)`
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##### `TEST_ASSERT_GREATER_THAN_HEX32 (threshold, actual)`
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##### `TEST_ASSERT_LESS_THAN (threshold, actual)`
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##### `TEST_ASSERT_LESS_THAN_INT (threshold, actual)`
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##### `TEST_ASSERT_LESS_THAN_INT8 (threshold, actual)`
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##### `TEST_ASSERT_LESS_THAN_INT16 (threshold, actual)`
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##### `TEST_ASSERT_LESS_THAN_INT32 (threshold, actual)`
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##### `TEST_ASSERT_LESS_THAN_UINT (threshold, actual)`
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##### `TEST_ASSERT_LESS_THAN_UINT8 (threshold, actual)`
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##### `TEST_ASSERT_LESS_THAN_UINT16 (threshold, actual)`
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##### `TEST_ASSERT_LESS_THAN_UINT32 (threshold, actual)`
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##### `TEST_ASSERT_LESS_THAN_HEX8 (threshold, actual)`
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##### `TEST_ASSERT_LESS_THAN_HEX16 (threshold, actual)`
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##### `TEST_ASSERT_LESS_THAN_HEX32 (threshold, actual)`
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### Integer Ranges (of all sizes)
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These assertions verify that the `expected` parameter is within +/- `delta`
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(inclusive) of the `actual` parameter. For example, if the expected value is 10
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and the delta is 3 then the assertion will fail for any value outside the range
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of 7 - 13.
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##### `TEST_ASSERT_INT_WITHIN (delta, expected, actual)`
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##### `TEST_ASSERT_INT8_WITHIN (delta, expected, actual)`
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##### `TEST_ASSERT_INT16_WITHIN (delta, expected, actual)`
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##### `TEST_ASSERT_INT32_WITHIN (delta, expected, actual)`
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##### `TEST_ASSERT_INT64_WITHIN (delta, expected, actual)`
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##### `TEST_ASSERT_UINT_WITHIN (delta, expected, actual)`
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##### `TEST_ASSERT_UINT8_WITHIN (delta, expected, actual)`
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##### `TEST_ASSERT_UINT16_WITHIN (delta, expected, actual)`
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##### `TEST_ASSERT_UINT32_WITHIN (delta, expected, actual)`
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##### `TEST_ASSERT_UINT64_WITHIN (delta, expected, actual)`
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##### `TEST_ASSERT_HEX_WITHIN (delta, expected, actual)`
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##### `TEST_ASSERT_HEX8_WITHIN (delta, expected, actual)`
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##### `TEST_ASSERT_HEX16_WITHIN (delta, expected, actual)`
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##### `TEST_ASSERT_HEX32_WITHIN (delta, expected, actual)`
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##### `TEST_ASSERT_HEX64_WITHIN (delta, expected, actual)`
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### Structs and Strings
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##### `TEST_ASSERT_EQUAL_PTR (expected, actual)`
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Asserts that the pointers point to the same memory location.
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##### `TEST_ASSERT_EQUAL_STRING (expected, actual)`
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Asserts that the null terminated (`'\0'`)strings are identical. If strings are
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of different lengths or any portion of the strings before their terminators
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differ, the assertion fails. Two NULL strings (i.e. zero length) are considered
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equivalent.
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##### `TEST_ASSERT_EQUAL_MEMORY (expected, actual, len)`
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Asserts that the contents of the memory specified by the `expected` and `actual`
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pointers is identical. The size of the memory blocks in bytes is specified by
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the `len` parameter.
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### Arrays
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`expected` and `actual` parameters are both arrays. `num_elements` specifies the
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number of elements in the arrays to compare.
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`_HEX` assertions produce failure messages with expected and actual array
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contents formatted in hexadecimal.
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For array of strings comparison behavior, see comments for
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`TEST_ASSERT_EQUAL_STRING` in the preceding section.
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Assertions fail upon the first element in the compared arrays found not to
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match. Failure messages specify the array index of the failed comparison.
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##### `TEST_ASSERT_EQUAL_INT_ARRAY (expected, actual, num_elements)`
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##### `TEST_ASSERT_EQUAL_INT8_ARRAY (expected, actual, num_elements)`
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##### `TEST_ASSERT_EQUAL_INT16_ARRAY (expected, actual, num_elements)`
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##### `TEST_ASSERT_EQUAL_INT32_ARRAY (expected, actual, num_elements)`
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##### `TEST_ASSERT_EQUAL_INT64_ARRAY (expected, actual, num_elements)`
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##### `TEST_ASSERT_EQUAL_UINT_ARRAY (expected, actual, num_elements)`
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##### `TEST_ASSERT_EQUAL_UINT8_ARRAY (expected, actual, num_elements)`
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##### `TEST_ASSERT_EQUAL_UINT16_ARRAY (expected, actual, num_elements)`
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##### `TEST_ASSERT_EQUAL_UINT32_ARRAY (expected, actual, num_elements)`
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##### `TEST_ASSERT_EQUAL_UINT64_ARRAY (expected, actual, num_elements)`
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##### `TEST_ASSERT_EQUAL_HEX_ARRAY (expected, actual, num_elements)`
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##### `TEST_ASSERT_EQUAL_HEX8_ARRAY (expected, actual, num_elements)`
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##### `TEST_ASSERT_EQUAL_HEX16_ARRAY (expected, actual, num_elements)`
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##### `TEST_ASSERT_EQUAL_HEX32_ARRAY (expected, actual, num_elements)`
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##### `TEST_ASSERT_EQUAL_HEX64_ARRAY (expected, actual, num_elements)`
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##### `TEST_ASSERT_EQUAL_PTR_ARRAY (expected, actual, num_elements)`
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##### `TEST_ASSERT_EQUAL_STRING_ARRAY (expected, actual, num_elements)`
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##### `TEST_ASSERT_EQUAL_MEMORY_ARRAY (expected, actual, len, num_elements)`
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`len` is the memory in bytes to be compared at each array element.
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### Each Equal (Arrays to Single Value)
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`expected` are single values and `actual` are arrays. `num_elements` specifies
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the number of elements in the arrays to compare.
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`_HEX` assertions produce failure messages with expected and actual array
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contents formatted in hexadecimal.
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Assertions fail upon the first element in the compared arrays found not to
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match. Failure messages specify the array index of the failed comparison.
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#### `TEST_ASSERT_EACH_EQUAL_INT (expected, actual, num_elements)`
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#### `TEST_ASSERT_EACH_EQUAL_INT8 (expected, actual, num_elements)`
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#### `TEST_ASSERT_EACH_EQUAL_INT16 (expected, actual, num_elements)`
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#### `TEST_ASSERT_EACH_EQUAL_INT32 (expected, actual, num_elements)`
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#### `TEST_ASSERT_EACH_EQUAL_INT64 (expected, actual, num_elements)`
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#### `TEST_ASSERT_EACH_EQUAL_UINT (expected, actual, num_elements)`
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#### `TEST_ASSERT_EACH_EQUAL_UINT8 (expected, actual, num_elements)`
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#### `TEST_ASSERT_EACH_EQUAL_UINT16 (expected, actual, num_elements)`
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#### `TEST_ASSERT_EACH_EQUAL_UINT32 (expected, actual, num_elements)`
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#### `TEST_ASSERT_EACH_EQUAL_UINT64 (expected, actual, num_elements)`
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#### `TEST_ASSERT_EACH_EQUAL_HEX (expected, actual, num_elements)`
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#### `TEST_ASSERT_EACH_EQUAL_HEX8 (expected, actual, num_elements)`
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#### `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)*
|