Index: tests/OFList/OFList.m
==================================================================
--- tests/OFList/OFList.m
+++ tests/OFList/OFList.m
@@ -14,21 +14,27 @@
 #import <stdio.h>
 #import <string.h>
 
 #import "OFString.h"
 #import "OFList.h"
+
+#ifndef _WIN32
+#define ZD "%zd"
+#else
+#define ZD "%u"
+#endif
 
 #define NUM_TESTS 5
 #define SUCCESS								\
 {									\
-	printf("\r\033[1;%dmTests successful: %zd/%d\033[0m",		\
+	printf("\r\033[1;%dmTests successful: " ZD "/%d\033[0m",	\
 	    (i == NUM_TESTS - 1 ? 32 : 33), i + 1, NUM_TESTS);		\
 	fflush(stdout);							\
 }
 #define FAIL								\
 {									\
-	printf("\r\033[K\033[1;31mTest %zd/%d failed!\033[m\n",		\
+	printf("\r\033[K\033[1;31mTest " ZD "/%d failed!\033[m\n",	\
 	    i + 1, NUM_TESTS);						\
 	return 1;							\
 }
 #define CHECK(cond)							\
 	if (cond)							\

Index: tests/OFString/OFString.m
==================================================================
--- tests/OFString/OFString.m
+++ tests/OFString/OFString.m
@@ -14,18 +14,24 @@
 #import <stdio.h>
 #import <string.h>
 
 #import "OFString.h"
 #import "OFExceptions.h"
+
+#ifndef _WIN32
+#define ZD "%zd"
+#else
+#define ZD "%u"
+#endif
 
 #define NUM_TESTS 10
 #define SUCCESS								\
-	printf("\r\033[1;%dmTests successful: %zd/%d\033[0m",		\
+	printf("\r\033[1;%dmTests successful: " ZD "/%d\033[0m",	\
 	    (i == NUM_TESTS - 1 ? 32 : 33), i + 1, NUM_TESTS);		\
 	fflush(stdout);
 #define FAIL								\
-	printf("\r\033[K\033[1;31mTest %zd/%d failed!\033[m\n",		\
+	printf("\r\033[K\033[1;31mTest " ZD "/%d failed!\033[m\n",	\
 	    i + 1, NUM_TESTS);						\
 	return 1;
 #define CHECK(cond)							\
 	if (cond) {							\
 		SUCCESS							\

Index: tests/OFXMLFactory/OFXMLFactory.m
==================================================================
--- tests/OFXMLFactory/OFXMLFactory.m
+++ tests/OFXMLFactory/OFXMLFactory.m
@@ -16,24 +16,30 @@
 #import <string.h>
 
 #import "OFXMLFactory.h"
 
 #define NUM_TESTS 10
+
+#ifndef _WIN32
+#define ZD "zd"
+#else
+#define ZD "u"
+#endif
 
 static size_t i;
 
 inline void
 check_result(char *result, const char *should)
 {
 	i++;
 
 	if (!strcmp(result, should)) {
-		printf("\r\033[1;%dmTests successful: %2zd/%d\033[0m",
+		printf("\r\033[1;%dmTests successful: %2" ZD "/%d\033[0m",
 		    (i == NUM_TESTS ? 32 : 33), i, NUM_TESTS);
 		fflush(stdout);
 	} else {
-		printf("\r\033[K\033[1;31mTest %zd/%d failed!\033[0m\n",
+		printf("\r\033[K\033[1;31mTest %" ZD "/%d failed!\033[0m\n",
 		    i, NUM_TESTS);
 		printf("%s is NOT expected result!\n", result);
 		exit(1);
 	}