Index: tests/OFString/OFString.m
==================================================================
--- tests/OFString/OFString.m
+++ tests/OFString/OFString.m
@@ -17,31 +17,50 @@
 /* TODO: Do real checks */
 
 int
 main()
 {
-	OFString *s1 = [OFString new: "foo"];
+	OFString *s1 = [OFString new: "test"];
 	OFString *s2 = [[OFString alloc] init: ""];
 	OFString *s3;
 	OFString *s4 = [OFString new];
 
-	[s2 append: "bar"];
+	[s2 append: "123"];
 	s3 = [s1 clone];
 
 	[s4 setTo: [s2 cString]];
 
-	printf("s1 = %s\n", [s1 cString]);
-	printf("s2 = %s\n", [s2 cString]);
-	printf("s3 = %s\n", [s3 cString]);
-	printf("s4 = %s\n", [s4 cString]);
-
-	[s1 append: [s2 cString]];
-	printf("s1 append s2 = %s\n", [s1 cString]);
-	printf("strlen(s1) = %zd, [s1 length] = %zd\n",
-	    strlen([s1 cString]), [s1 length]);
+	if (!strcmp([s1 cString], [s3 cString]))
+		puts("s1 and s3 match! GOOD!");
+	else {
+		puts("s1 and s3 don't match!");
+		return 1;
+	}
+
+	if (!strcmp([s2 cString], [s4 cString]))
+		puts("s2 and s4 match! GOOD!");
+	else {
+		puts("s1 and s3 don't match!");
+		return 1;
+	}
+
+	if (!strcmp([[s1 append: [s2 cString]] cString], "test123"))
+		puts("s1 appended with s2 is the expected string! GOOD!");
+	else {
+		puts("s1 appended with s2 is not the expected string!");
+		return 1;
+	}
+
+	if (strlen([s1 cString]) == [s1 length] && [s1 length] == 7)
+		puts("s1 has the expected length. GOOD!");
+	else {
+		puts("s1 does not have the expected length!");
+		return 1;
+	}
+
 	[s1 free];
 	[s2 free];
 	[s3 free];
 	[s4 free];
 
 	return 0;
 }

Index: tests/OFWideString/OFWideString.m
==================================================================
--- tests/OFWideString/OFWideString.m
+++ tests/OFWideString/OFWideString.m
@@ -7,41 +7,59 @@
  * This file is part of libobjfw. It may be distributed under the terms of the
  * Q Public License 1.0, which can be found in the file LICENSE included in
  * the packaging of this file.
  */
 
-#define _ISOC99_SOURCE
 #import <wchar.h>
 
 #import "OFWideString.h"
 
 /* TODO: Do real checks */
 
 int
 main()
 {
-	OFWideString *s1 = [OFWideString new: L"foo"];
+	OFWideString *s1 = [OFWideString new: L"test"];
 	OFWideString *s2 = [[OFWideString alloc] init: L""];
 	OFWideString *s3;
 	OFWideString *s4 = [OFWideString new];
 
-	[s2 append: L"bar"];
+	[s2 append: L"123"];
 	s3 = [s1 clone];
 
 	[s4 setTo: [s2 wcString]];
 
-	wprintf(L"s1 = %S\n", [s1 wcString]);
-	wprintf(L"s2 = %S\n", [s2 wcString]);
-	wprintf(L"s3 = %S\n", [s3 wcString]);
-	wprintf(L"s4 = %S\n", [s4 wcString]);
-
-	[s1 append: [s2 wcString]];
-	wprintf(L"s1 append s2 = %S\n", [s1 wcString]);
-	wprintf(L"wcslen(s1) = %zd, [s1 length] = %zd\n",
-	    wcslen([s1 wcString]), [s1 length]);
+	if (!wcscmp([s1 wcString], [s3 wcString]))
+		puts("s1 and s3 match! GOOD!");
+	else {
+		puts("s1 and s3 don't match!");
+		return 1;
+	}
+
+	if (!wcscmp([s2 wcString], [s4 wcString]))
+		puts("s2 and s4 match! GOOD!");
+	else {
+		puts("s1 and s3 don't match!");
+		return 1;
+	}
+
+	if (!wcscmp([[s1 append: [s2 wcString]] wcString], L"test123"))
+		puts("s1 appended with s2 is the expected string! GOOD!");
+	else {
+		puts("s1 appended with s2 is not the expected string!");
+		return 1;
+	}
+
+	if (wcslen([s1 wcString]) == [s1 length] && [s1 length] == 7)
+		puts("s1 has the expected length. GOOD!");
+	else {
+		puts("s1 does not have the expected length!");
+		return 1;
+	}
+
 	[s1 free];
 	[s2 free];
 	[s3 free];
 	[s4 free];
 
 	return 0;
 }