MinUnit, an unit test framework for C and a programming pearl

Sometimes on the Internet you find a programming pearl and you must share with others what you have found.

I’ve found a programming pearl here:

http://www.jera.com/techinfo/jtns/jtn002.html

The pearl is:

/* file: minunit.h */
#define mu_assert(message, test) do { if (!(test)) return message; } while (0)
#define mu_run_test(test) do { char *message = test(); tests_run++; \
                                if (message) return message; } while (0)
extern int tests_run;

Just 3 lines of clear, readable code, represent an unit test framework for C. You can use that like this:

 #include <stdio.h>
 #include "minunit.h"
 
 int tests_run = 0;
 
 int foo = 7;
 int bar = 4;
 
 static char * test_foo() {
     mu_assert("error, foo != 7", foo == 7);
     return 0;
 }
 
 static char * test_bar() {
     mu_assert("error, bar != 5", bar == 5);
     return 0;
 }
 
 static char * all_tests() {
     mu_run_test(test_foo);
     mu_run_test(test_bar);
     return 0;
 }
 
 int main(int argc, char **argv) {
     char *result = all_tests();
     if (result != 0) {
         printf("%s\n", result);
     }
     else {
         printf("ALL TESTS PASSED\n");
     }
     printf("Tests run: %d\n", tests_run);
 
     return result != 0;
 }

Remember what Uncle Bob said?
You must express your problem in the chosen programming language in a manner that the language must appear to be designed exactly for the problem that you are trying to solve.

Isn’t that wonderful?