UnitTest

UnitTest is a simple unit testing framework for C code. UnitTest provides facilities for making assertions, mocking (faking) functions and a means for running unit tests. UnitTest is minimalistic in its approach to unit testing. UnitTest is intended to be used with embedded systems.

Documentation

See the documentation page for details on how to setup and use the framework.

Dependencies

• C99 compatible C compiler
• bash version 3.1 or higher

Quick Reference

File Scope Declarations

Macro	Description
Mock_Vars(depth)	Declare framework state; depth = max calls tracked per mock
Mock_Void(fn) / Mock_VoidN(fn, ...)	Declare a void mock (0–5 args)
Mock_Value(ret_t, fn) / Mock_ValueN(ret_t, fn, ...)	Declare a value-returning mock (0–5 args)

Life Cycle (in main)

Macro	Description
Assert_Init()	Load running assertion count from assertions.txt
Assert_Save()	Write assertion count back to assertions.txt

setUp Convention (call at top of every test)

Macro	Description
Test_Init()	Reset call-order tracking and notes
Mock_Reset(fn)	Reset call count, argument history, and return value for a mock

Mock Control

Macro	Description
Mock_Returns(fn, val)	Return val on every call
Mock_ReturnsSequence(fn, len, seq)	Return values in sequence; repeat last when exhausted
Mock_Custom(fn, impl)	Delegate to a custom implementation function

Value Assertions

Macro	Description
Assert_Equals(expected, actual)	Integer equality
Assert_NotEquals(expected, actual)	Integer inequality
Assert_EqualsLong(expected, actual)	64-bit integer equality
Assert_EqualsFloat(expected, actual, delta)	Float equality within tolerance
Assert_ArrayEquals(len, expected, actual)	Element-wise array equality
Assert_StrEquals(expected, actual)	String equality
Assert_True(actual)	Non-zero
Assert_False(actual)	Zero
Assert_IsNull(actual)	Pointer is NULL
Assert_IsNotNull(actual)	Pointer is not NULL
Assert_Fail(msg)	Unconditional failure
Assert_Note(msg)	Set a label shown on the next failure

Mock Call Assertions

Macro	Description
Assert_CalledOnce(fn)	Called exactly once
Assert_NotCalled(fn)	Never called
Assert_CallCount(n, fn)	Called exactly n times
Assert_CallOrder(fn1st, fn2nd)	fn1st was called before fn2nd
Assert_Returned(fn, expected)	Mock returned expected at least once
Assert_CalledN(fn, ...)	At least one call had these args (N = arg count)
Assert_CalledFirstN(fn, ...)	First call had these args
Assert_CalledLastN(fn, ...)	Last call had these args
Assert_CalledNN(n, fn, ...)	Nth call (1-based) had these args
Assert_AllCallsEqualsN(fn, val)	Every call's last arg == val
Assert_AllCallsLessThanN(fn, val)	Every call's last arg < val
Assert_AllCallsGreaterThanN(fn, val)	Every call's last arg > val

License

UnitTest is published under the MIT License. The base MIT license has been modified to prohibit the use of NAND Gate Technologies LLC in any promotion.

(C) NAND Gate Technologies LLC 2026