C header-only unit testing with FCTX

Just a quick hat tip to FCTX, a library I've found invaluable these past few months. FCTX provides header-only unit testing for C. Sure, if you're in C++ land there's a ton of xUnit-like frameworks available (with Boost.Test being my favorite), but for vanilla C projects FCTX wins hands down.

As an example, here's something I put together for a Stack Overflow response:

	#include <ctype.h>
	void trim(char * const a)
	{
	char *p = a, *q = a;
	while (isspace(*q)) ++q;
	while (*q) *p++ = *q++;
	*p = '\0';
	while (p > a && isspace(*--p)) *p = '\0';
	}
	/* See http://fctx.wildbearsoftware.com/ */
	#include "fct.h"
	FCT_BGN()
	{
	FCT_QTEST_BGN(trim)
	{
	{ char s[] = ""; trim(s); fct_chk_eq_str("", s); } // Trivial
	{ char s[] = " "; trim(s); fct_chk_eq_str("", s); } // Trivial
	{ char s[] = "\t"; trim(s); fct_chk_eq_str("", s); } // Trivial
	{ char s[] = "a"; trim(s); fct_chk_eq_str("a", s); } // NOP
	{ char s[] = "abc"; trim(s); fct_chk_eq_str("abc", s); } // NOP
	{ char s[] = " a"; trim(s); fct_chk_eq_str("a", s); } // Leading
	{ char s[] = " a c"; trim(s); fct_chk_eq_str("a c", s); } // Leading
	{ char s[] = "a "; trim(s); fct_chk_eq_str("a", s); } // Trailing
	{ char s[] = "a c "; trim(s); fct_chk_eq_str("a c", s); } // Trailing
	{ char s[] = " a "; trim(s); fct_chk_eq_str("a", s); } // Both
	{ char s[] = " a c "; trim(s); fct_chk_eq_str("a c", s); } // Both
	// Villemoes pointed out an edge case that corrupted memory. Thank you.
	// http://stackoverflow.com/questions/122616/#comment23332594_4505533
	{
	char s[] = "a "; // Buffer with whitespace before s + 2
	trim(s + 2); // Trim " " containing only whitespace
	fct_chk_eq_str("", s + 2); // Ensure correct result from the trim
	fct_chk_eq_str("a ", s); // Ensure preceding buffer not mutated
	}
	}
	FCT_QTEST_END();
	}
	FCT_END();

view raw trim.c hosted with ❤ by GitHub

The logic isn't rocket science, of course. But testing it in C without resorting to external libraries and complicated makefiles shouldn't be rocket science either. Provided that fct.h is in the same directory, this source will compile and run.