A unit testing system for C, contained in 1 file. It doesn't use dynamic allocation or depend on anything beyond ANSI C89, and the test scaffolding should build without warnings under -Wall -pedantic.

To use, just #include greatest.h in your project.

Note that there are some compile time options, and slightly nicer syntax for parametric testing (running tests with arguments) is available if compiled with -std=c99.

Also, I wrote a blog post with more information.

• ASSERT(COND)/ASSERTm(MSG, COND)

  Assert that COND evaluates to a true value.

• ASSERT_FALSE(COND)/ASSERT_FAILm(MSG, COND)

  Assert that COND evaluates to a false value.

• ASSERT_EQ(EXPECTED, ACTUAL)/ASSERT_EQm(MSG, EXPECTED, ACTUAL)

  Assert that EXPECTED == ACTUAL. (To compare structures, use ASSERT with your own function to compare the structures' members.)

• ASSERT_STR_EQ(EXPECTED, ACTUAL)/ASSERT_STR_EQm(MSG, EXPECTED, ACTUAL)

  Assert that strcmp(EXPECTED, ACTUAL) == 0.

In all cases, the m version allows you to pass in a customized failure message. If an assertion without a custom message fails, greatest uses C preprocessor stringification to simply print the assertion's parameters.

#include "greatest.h"

TEST x_should_equal_1() {
    int x = 1;
    ASSERT_EQ(1, x);                              /* default message */
    ASSERT_EQm("yikes, x doesn't equal 1", 1, x); /* custom message */
    PASS();
}

SUITE(the_suite) {
    RUN_TEST(x_should_equal_1);
}

/* Add definitions that need to be in the test runner's main file. */
GREATEST_MAIN_DEFS();

int main(int argc, char **argv) {
    GREATEST_MAIN_BEGIN();      /* command-line arguments, initialization. */
    RUN_SUITE(the_suite);
    GREATEST_MAIN_END();        /* display results */
}

Output:

$ make simple && ./simple
cc -g -Wall -Werror -pedantic    simple.c   -o simple

* Suite the_suite:
.
1 tests - 1 pass, 0 fail, 0 skipped (5 ticks, 0.000 sec)

Total: 1 tests (47 ticks, 0.000 sec)
Pass: 1, fail: 0, skip: 0.

Test cases should call assertions and then end in PASS(), SKIP(), FAIL(), or one of their message variants (e.g. SKIPm("TODO");).

Tests and suites are just functions, so normal C scoping rules apply.

(For more examples, look at example.c and example-suite.c.)

Test runners build with the following command line options:

Usage: (test_runner) [-hlfv] [-s SUITE] [-t TEST]
  -h        print this Help
  -l        List suites and their tests, then exit
  -f        Stop runner after first failure
  -v        Verbose output
  -s SUITE  only run suite w/ name containing SUITE substring
  -t TEST   only run test w/ name containing TEST substring

If you want to run multiple test suites in parallel, look at parade.

All the Macros exist with the unprefixed notation and with the prefixed notation, for example:

SUITE is the same as GREATEST_SUITE

Checkout the source for the entire list.

If you want color output (PASS in green, FAIL in red, etc.), you can pipe the output through the included greenest script:

$ ./example -v | greenest

greatest itself doesn't have built-in coloring to stay small and portable.