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 *a)
{
    char *b = a;
    while (isspace(*b))   ++b;
    while (*b)            *a++ = *b++;
    *a = '\0';
    while (isspace(*--a)) *a = '\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
    }
    FCT_QTEST_END();
}
FCT_END();

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.