diff --git a/tests/failmalloc.c b/tests/failmalloc.c
index 6ca39165..4bf83ca5 100644
--- a/tests/failmalloc.c
+++ b/tests/failmalloc.c
@@ -43,13 +43,13 @@ int main() {
 
   /* initialize the CUnit test registry */
   if (CUE_SUCCESS != CU_initialize_registry())
-    return CU_get_error();
+    return (int)CU_get_error();
 
   /* add a suite to the registry */
   pSuite = CU_add_suite("libnghttp2_TestSuite", init_suite1, clean_suite1);
   if (NULL == pSuite) {
     CU_cleanup_registry();
-    return CU_get_error();
+    return (int)CU_get_error();
   }
 
   /* add the tests to the suite */
@@ -62,7 +62,7 @@ int main() {
       !CU_add_test(pSuite, "failmalloc_frame", test_nghttp2_frame) ||
       !CU_add_test(pSuite, "failmalloc_hd", test_nghttp2_hd)) {
     CU_cleanup_registry();
-    return CU_get_error();
+    return (int)CU_get_error();
   }
 
   /* Run all tests using the CUnit Basic interface */
@@ -74,6 +74,6 @@ int main() {
     return (int)num_tests_failed;
   } else {
     printf("CUnit Error: %s\n", CU_get_error_msg());
-    return CU_get_error();
+    return (int)CU_get_error();
   }
 }
diff --git a/tests/main.c b/tests/main.c
index 41e52017..aa584ad8 100644
--- a/tests/main.c
+++ b/tests/main.c
@@ -55,13 +55,13 @@ int main() {
 
   /* initialize the CUnit test registry */
   if (CUE_SUCCESS != CU_initialize_registry())
-    return CU_get_error();
+    return (int)CU_get_error();
 
   /* add a suite to the registry */
   pSuite = CU_add_suite("libnghttp2_TestSuite", init_suite1, clean_suite1);
   if (NULL == pSuite) {
     CU_cleanup_registry();
-    return CU_get_error();
+    return (int)CU_get_error();
   }
 
   /* add the tests to the suite */
@@ -416,7 +416,7 @@ int main() {
                    test_nghttp2_bufs_next_present) ||
       !CU_add_test(pSuite, "bufs_realloc", test_nghttp2_bufs_realloc)) {
     CU_cleanup_registry();
-    return CU_get_error();
+    return (int)CU_get_error();
   }
 
   /* Run all tests using the CUnit Basic interface */
@@ -428,6 +428,6 @@ int main() {
     return (int)num_tests_failed;
   } else {
     printf("CUnit Error: %s\n", CU_get_error_msg());
-    return CU_get_error();
+    return (int)CU_get_error();
   }
 }