diff --git a/tests/test_kem.c b/tests/test_kem.c
index d2e649875..d6f480253 100644
--- a/tests/test_kem.c
+++ b/tests/test_kem.c
@@ -167,7 +167,7 @@ int main(int argc, char **argv) {
 	OQS_STATUS rc;
 #if OQS_USE_PTHREADS_IN_TESTS
 	// don't run Classic McEliece or LEDAcryptKEM-LT52 in threads because of large stack usage
-	if ((strnstr(alg_name, "Classic-McEliece", 16) == NULL) && (strnstr(alg_name, "LEDAcryptKEM-LT52", 17) == NULL)) {
+	if ((strstr(alg_name, "Classic-McEliece") == NULL) && (strstr(alg_name, "LEDAcryptKEM-LT52") == NULL)) {
 		pthread_t thread;
 		void *status;
 		int trc = pthread_create(&thread, NULL, test_wrapper, alg_name);
diff --git a/tests/test_sig.c b/tests/test_sig.c
index 10b5e9309..308c28661 100644
--- a/tests/test_sig.c
+++ b/tests/test_sig.c
@@ -127,7 +127,7 @@ int main(int argc, char **argv) {
 	OQS_STATUS rc;
 #if OQS_USE_PTHREADS_IN_TESTS
 	// don't run Rainbow IIIc and Vc in threads because of large stack usage
-	if ((strnstr(alg_name, "Rainbow-IIIc", 12) == NULL) && (strnstr(alg_name, "Rainbow-Vc", 10) == NULL)) {
+	if ((strstr(alg_name, "Rainbow-IIIc") == NULL) && (strstr(alg_name, "Rainbow-Vc") == NULL)) {
 		pthread_t thread;
 		void *status;
 		int trc = pthread_create(&thread, NULL, test_wrapper, alg_name);