diff --git a/tests/test_charcase.c b/tests/test_charcase.c
index cb2456b..e20ca33 100644
--- a/tests/test_charcase.c
+++ b/tests/test_charcase.c
@@ -14,6 +14,8 @@ int main(int argc, char **argv)
 	MC_SET_DEBUG(1);
 
 	test_case_parse();
+
+	return 0;
 }
 
 /* make sure only lowercase forms are parsed in strict mode */
diff --git a/tests/test_double_serializer.c b/tests/test_double_serializer.c
index 2cec24f..ddace8e 100644
--- a/tests/test_double_serializer.c
+++ b/tests/test_double_serializer.c
@@ -86,12 +86,16 @@ int main()
 	/* Test NaN handling */
 	obj = json_object_new_double(zero_dot_zero / zero_dot_zero);
 	printf("obj(0.0/0.0)=%s\n", json_object_to_json_string(obj));
+	json_object_put(obj);
 
 	/* Test Infinity and -Infinity handling */
 	obj = json_object_new_double(1.0/zero_dot_zero);
 	printf("obj(1.0/0.0)=%s\n", json_object_to_json_string(obj));
+	json_object_put(obj);
 
 	obj = json_object_new_double(-1.0/zero_dot_zero);
 	printf("obj(-1.0/0.0)=%s\n", json_object_to_json_string(obj));
+	json_object_put(obj);
 
+	return 0;
 }
diff --git a/tests/test_locale.c b/tests/test_locale.c
index 7d6541a..be02727 100644
--- a/tests/test_locale.c
+++ b/tests/test_locale.c
@@ -58,5 +58,7 @@ int main(int argc, char **argv)
 
 	printf("new_obj.to_string()=%s\n", json_object_to_json_string_ext(new_obj,JSON_C_TO_STRING_NOZERO));
 	json_object_put(new_obj);
+
+	return 0;
 }
 
diff --git a/tests/test_parse.c b/tests/test_parse.c
index 8f3c922..0c8fc4b 100644
--- a/tests/test_parse.c
+++ b/tests/test_parse.c
@@ -26,6 +26,8 @@ int main(void)
 	puts(separator);
 	test_incremental_parse();
 	puts(separator);
+
+	return 0;
 }
 
 static json_c_visit_userfunc clear_serializer;
diff --git a/tests/test_visit.c b/tests/test_visit.c
index f2ffe8c..4046133 100644
--- a/tests/test_visit.c
+++ b/tests/test_visit.c
@@ -49,6 +49,8 @@ int main(void)
 	printf("================================\n\n");
 
 	json_object_put(jso);
+
+	return 0;
 }