Add unit test

unit_test.c

@@ -260,12 +260,14 @@ int main(void) {
 
   {
     /* Example more complex regular expression */
-    static const char * str = "aa 1234 xy\nz";
-    static const char * regex = "aa ([0-9]*) *([x-z]*)";
-    struct slre_cap caps[2];
-    ASSERT(slre_match(regex, str, strlen(str), caps, 2, 0) > 0);
+    static const char * str = "aa 1234 xy\nxyz";
+    static const char * regex = "aa ([0-9]*) *([x-z]*)\\s+xy([yz])";
+    struct slre_cap caps[3];
+    ASSERT(slre_match(regex, str, strlen(str), caps, 3, 0) > 0);
     ASSERT(caps[0].len == 4);
-    ASSERT(caps[1].len == 2); /* Fails here */
+    ASSERT(caps[1].len == 2);
+    ASSERT(caps[2].len == 1);
+    ASSERT(caps[2].ptr[0] == 'z');
   }
 
   printf("Unit test %s (total test: %d, failed tests: %d)\n",