diff --git a/tests/test_options.c b/tests/test_options.c
index fd032b4f..35082ed9 100644
--- a/tests/test_options.c
+++ b/tests/test_options.c
@@ -393,9 +393,12 @@ t_access_option5(void) {
 
 static void
 t_access_option6(void) {
+  coap_log_t level = coap_get_log_level();
   const uint8_t teststr[] = { 0xf2, 'a', 'b' };
 
+  coap_set_log_level(LOG_CRIT);
   CU_ASSERT(coap_opt_delta((coap_opt_t *)teststr) == 0);
+  coap_set_log_level(level);
   CU_ASSERT(coap_opt_length((coap_opt_t *)teststr) == 0);
   CU_ASSERT_PTR_EQUAL(coap_opt_value((coap_opt_t *)teststr), NULL);
   CU_ASSERT(coap_opt_size((coap_opt_t *)teststr) == 0);
diff --git a/tests/test_pdu.c b/tests/test_pdu.c
index 1ae8460c..9d317e7d 100644
--- a/tests/test_pdu.c
+++ b/tests/test_pdu.c
@@ -599,6 +599,7 @@ t_encode_pdu10(void) {
 
 static void
 t_encode_pdu11(void) {
+  coap_log_t level = coap_get_log_level();
   /* data too long for PDU */
   size_t old_max = pdu->max_size;
   int result;
@@ -606,7 +607,9 @@ t_encode_pdu11(void) {
   coap_pdu_clear(pdu, 8);	/* clear PDU, with small maximum */
 
   CU_ASSERT(pdu->data == NULL);
+  coap_set_log_level(LOG_CRIT);
   result = coap_add_data(pdu, 10, (unsigned char *)"0123456789");
+  coap_set_log_level(level);
 
   CU_ASSERT(result == 0);
   CU_ASSERT(pdu->data == NULL);