diff --git a/tests/contrib/test_hhash.c b/tests/contrib/test_hhash.c
index 43577ac81dd77edba012d2ce931d9566c859817f..707db6a119a42ea5e229baeea230be5f3e541c50 100644
--- a/tests/contrib/test_hhash.c
+++ b/tests/contrib/test_hhash.c
@@ -134,8 +134,7 @@ int main(int argc, char *argv[])
 			break;
 		}
 		prev = cur;
-		int strl = strlen(cur);
-		assert(strl + 1 == len);
+		assert(strlen(cur) + 1 == len);
 		hhash_iter_next(&it);
 	}
 	ok(hhash_iter_finished(&it), "hhash: passed order index checks");
diff --git a/tests/contrib/test_strtonum.c b/tests/contrib/test_strtonum.c
index 92260364807c637427b7ed8abca430fdd6ce7b3f..fb30d74ef0119053e6bde138388c2b49bea479e1 100644
--- a/tests/contrib/test_strtonum.c
+++ b/tests/contrib/test_strtonum.c
@@ -68,7 +68,7 @@ static void test_int(const char *in, int expected, int errcode)
 
 // mute warn_unused_result
 #define asprintf(args, ...) do { \
-	int r = (asprintf)(args, ##__VA_ARGS__); assert(r >= 0); \
+	int r = (asprintf)(args, ##__VA_ARGS__); assert(r >= 0); (void)r; \
 } while (0);
 
 int main(int argc, char *argv[])
diff --git a/tests/journal.c b/tests/journal.c
index 967f1bca7a0b966f855df587a99ec8220b715471..2873a0c59a320d192950e00b6de9d6615ce144bf 100644
--- a/tests/journal.c
+++ b/tests/journal.c
@@ -50,6 +50,7 @@ static void init_soa(knot_rrset_t *rr, const uint32_t serial, const knot_dname_t
 	assert(serial < 256);
 	uint8_t soa_data[MIN_SOA_SIZE] = { 0, 0, 0, 0, 0, serial };
 	int ret = knot_rrset_add_rdata(rr, soa_data, sizeof(soa_data), 3600, NULL);
+	(void)ret;
 	assert(ret == KNOT_EOK);
 }
 
@@ -71,6 +72,7 @@ static void init_random_rr(knot_rrset_t *rr , const knot_dname_t *apex)
 	randstr((char *)(txt + 1), RAND_RR_PAYLOAD);
 
 	int ret = knot_rrset_add_rdata(rr, txt, RAND_RR_PAYLOAD, 3600, NULL);
+	(void)ret;
 	assert(ret == KNOT_EOK);
 }
 
@@ -78,6 +80,7 @@ static void init_random_rr(knot_rrset_t *rr , const knot_dname_t *apex)
 static void init_random_changeset(changeset_t *ch, const uint32_t from, const uint32_t to, const size_t size, const knot_dname_t *apex)
 {
 	int ret = changeset_init(ch, apex);
+	(void)ret;
 	assert(ret == KNOT_EOK);
 
 	// Add SOAs
@@ -98,6 +101,7 @@ static void init_random_changeset(changeset_t *ch, const uint32_t from, const ui
 		knot_rrset_t rr;
 		init_random_rr(&rr, apex);
 		int ret = changeset_add_rrset(ch, &rr, 0);
+		(void)ret;
 		assert(ret == KNOT_EOK);
 		knot_rrset_clear(&rr, NULL);
 	}
@@ -107,6 +111,7 @@ static void init_random_changeset(changeset_t *ch, const uint32_t from, const ui
 		knot_rrset_t rr;
 		init_random_rr(&rr, apex);
 		int ret = changeset_rem_rrset(ch, &rr, 0);
+		(void)ret;
 		assert(ret == KNOT_EOK);
 		knot_rrset_clear(&rr, NULL);
 	}
@@ -220,6 +225,7 @@ static void test_store_load(const char *jfilename)
 	changeset_t ch;
 	init_random_changeset(&ch, 0, 1, 128, apex);
 	int ret = journal_store_changeset(&ch, jfilename, filesize);
+	(void)ret;
 	ok(ret == KNOT_EOK, "journal: store changeset");
 	list_t l;
 	init_list(&l);
diff --git a/tests/node.c b/tests/node.c
index 28c5a3066b714a1c7e09d3522fc8d80e5b2ac0ec..824afcfc2f99050355a62007542968d32c6863fe 100644
--- a/tests/node.c
+++ b/tests/node.c
@@ -31,6 +31,7 @@ static knot_rrset_t *create_dummy_rrset(const knot_dname_t *owner,
 	memcpy(wire, "testtest", strlen("testtest"));
 	int ret = knot_rrset_add_rdata(r, wire, strlen("testtest"), 3600, NULL);
 	assert(ret == KNOT_EOK);
+	(void)ret;
 	return r;
 }
 
@@ -44,6 +45,7 @@ static knot_rrset_t *create_dummy_rrsig(const knot_dname_t *owner,
 	wire_write_u16(wire, type);
 	int ret = knot_rrset_add_rdata(r, wire, sizeof(uint16_t), 3600, NULL);
 	assert(ret == KNOT_EOK);
+	(void)ret;
 	return r;
 }
 
diff --git a/tests/requestor.c b/tests/requestor.c
index dd657d3804f6554c0bd42d3f74e0ed7109439b2d..d3afc5ac394bcf41a51bbe766cb1d6a9f8b44556 100644
--- a/tests/requestor.c
+++ b/tests/requestor.c
@@ -142,6 +142,7 @@ int main(int argc, char *argv[])
 
 	/* Start responder. */
 	int ret = listen(responder_fd, 10);
+	(void)ret;
 	assert(ret == 0);
 	pthread_t thread;
 	pthread_create(&thread, 0, responder_thread, &responder_fd);
diff --git a/tests/zone_update.c b/tests/zone_update.c
index c3dc262e8945041e845ad0c50e4c451faa5ef88a..ef3f2cb582a883db8a676d811f071460c28f88cd 100644
--- a/tests/zone_update.c
+++ b/tests/zone_update.c
@@ -60,6 +60,7 @@ static void process_rr(zs_scanner_t *scanner)
 	int ret = knot_rrset_add_rdata(&rrset, scanner->r_data,
 	                               scanner->r_data_length,
 	                               scanner->r_ttl, NULL);
+	(void)ret;
 	assert(ret == KNOT_EOK);
 }
 
@@ -296,6 +297,7 @@ int main(int argc, char *argv[])
 
 	/* Load test configuration. */
 	int ret = test_conf(conf_str, NULL);
+	(void)ret;
 	assert(ret == KNOT_EOK);
 
 	/* Set up empty zone */