diff --git a/tests/libtest/lib1515.c b/tests/libtest/lib1515.c
index c72554a3b..b879836f9 100644
--- a/tests/libtest/lib1515.c
+++ b/tests/libtest/lib1515.c
@@ -36,7 +36,7 @@
 #define DNS_TIMEOUT 1
 
 #if defined(WIN32) || defined(_WIN32)
-#define sleep(s) Sleep(s * 1000)
+#define sleep(sec) Sleep ((sec)*1000)
 #endif
 
 static int debug_callback(CURL *curl, curl_infotype info, char *msg,
diff --git a/tests/libtest/lib1531.c b/tests/libtest/lib1531.c
index 4a4dc133a..5c9399559 100644
--- a/tests/libtest/lib1531.c
+++ b/tests/libtest/lib1531.c
@@ -107,7 +107,7 @@ int test(char *URL)
        curl_multi_fdset() doc. */
 
     if(maxfd == -1) {
-#ifdef _WIN32
+#if defined(WIN32) || defined(_WIN32)
       Sleep(100);
       rc = 0;
 #else
diff --git a/tests/server/util.h b/tests/server/util.h
index 7b4ec1626..236d4550e 100644
--- a/tests/server/util.h
+++ b/tests/server/util.h
@@ -37,16 +37,16 @@ extern const char *path;
 /* global variable, log file name */
 extern const char *serverlogfile;
 
-#ifdef WIN32
+#if defined(WIN32) || defined(_WIN32)
 #include <process.h>
 #include <fcntl.h>
 
-#define sleep(sec)   Sleep ((sec)*1000)
+#define sleep(sec) Sleep ((sec)*1000)
 
 #undef perror
 #define perror(m) win32_perror(m)
 void win32_perror(const char *msg);
-#endif  /* WIN32 */
+#endif  /* WIN32 or _WIN32 */
 
 #ifdef USE_WINSOCK
 void win32_init(void);