Unit Tests for C, in a single header.

test.h

#ifndef TEST_H_
#define TEST_H_

/* Unit testing framework.
 * 
 * Copyright (c) 2014, Jim Ingram <ingramj@gmail.com>
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * http://jingram.sdf.org/2014/11/29/unit-tests-for-c-in-two-macros.html
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>

/*
 * Begin a new test definition, with the given name.
 */
#define BEGIN_TEST(name)                        \
    static int test_##name(void)                \
    {                                           \
        pid_t pid = fork();                     \
        if (pid < 0) {                          \
            return -1;                          \
        }                                       \
        if (pid == 0) {                         \
            int failed = 0;

/*
 * End a test definition and set its expected exit status.
 */
#define END_TEST(expected)                                      \
            exit(failed ? !expected : expected);                \
        } else {                                                \
            int status;                                         \
            waitpid(pid, &status, 0);                           \
            if (WIFEXITED(status)) {                            \
                return WEXITSTATUS(status) == expected ? 0 : 1; \
            }                                                   \
            return -1;                                          \
        }                                                       \
    }


/*
 * Set the `failed` flag to 1 for this test, if `cond` evaluates to true.
 */
#define FAIL_IF(cond)     failed = (cond) ? 1 : failed

/*
 * Set the `failed` flag to 1 for this test, unless `cond` evaluates to true.
 */
#define FAIL_UNLESS(cond) failed = (cond) ? failed : 1


/*
 * Container for summary data about a series of tests.
 */
typedef struct {
    int passed;
    int failed;
    int errors;
} tests_summary;

/*
 * Reset passed, failed, and error counts in a `tests_summary` struct.
 */
static inline void reset_summary(tests_summary *summary)
{
    summary->passed = 0;
    summary->failed = 0;
    summary->errors = 0;
}

/*
 * Print passed, failed, errors, and total tests run from a
 * `tests_summary` struct.
 */
static inline void print_summary(tests_summary *summary)
{
    printf("passed : %d\nfailed : %d\nerrors : %d\ntotal  : %d\n",
           summary->passed, summary->failed, summary->errors,
           summary->passed + summary->failed + summary->errors);
}


/*
 * Run the named test, and update `summary` with the result.
 */
#define RUN_TEST(name, summary)                 \
    do {                                        \
        int ret;                                \
        printf("%s: ", #name);                  \
        fflush(stdout);                         \
        ret = test_##name();                    \
        if (ret == 0) {                         \
            printf("passed\n");                 \
            (summary).passed++;                 \
        } else if (ret == 1) {                  \
            printf("failed\n");                 \
            (summary).failed++;                 \
        } else {                                \
            printf("failed to to an error\n");  \
            (summary).errors++;                 \
        }                                       \
    } while (0)

#endif