C: add test for asprintf.c

c-programming/asprintf.c

@@ -34,3 +34,33 @@ ssize_t asprintf(char** strp, char* format, ...) {
 
 	return result;
 }
+
+#ifdef TEST
+# include <inttypes.h>
+# include <math.h>
+# include <stdbool.h>
+# define PRINT_ASSERT(caption, test) do {                                     \
+    bool test_result = (test);                                                \
+    printf("[test] " caption ": %s\n", test_result ? "OK" : "failed");        \
+    if (test_result == false)                                                 \
+        exit(EXIT_FAILURE);                                                   \
+} while (0);
+
+int main(void) {
+	const char* world = " world";
+
+	char* output;
+	size_t result = asprintf(&output, "Hello%s! -- Unsigned 32-bit type is "
+		"constrained to lie\nwithin the range of integer values from "
+		"%" PRIu32 " to %" PRIu32 " inclusive.", world, 0,
+		(uint32_t) (powf(2.0f, 32.0f) - 1.0f));
+
+	PRINT_ASSERT("segmentation fault", true);
+	PRINT_ASSERT("no errors", errno == 0);
+	PRINT_ASSERT("zero termination test", output[result] == '\0');
+
+	printf("[asprintf (%zu)] '%s'\n", result, output);
+
+	return 0;
+}
+#endif