diff --git a/src/systemcmds/tests/test_mixer.cpp b/src/systemcmds/tests/test_mixer.cpp
index 4da4b77c1e..18e0e8e256 100644
--- a/src/systemcmds/tests/test_mixer.cpp
+++ b/src/systemcmds/tests/test_mixer.cpp
@@ -144,7 +144,7 @@ int test_mixer(int argc, char *argv[])
 
 	while (transmitted < loaded) {
 
-		unsigned	text_length = (loaded - transmitted > chunk_size) ? chunk_size : loaded - transmitted;
+		unsigned text_length = (loaded - transmitted > chunk_size) ? chunk_size : loaded - transmitted;
 
 		/* check for overflow - this would be really fatal */
 		if ((mixer_text_length + text_length + 1) > sizeof(mixer_text)) {
@@ -209,7 +209,7 @@ int test_mixer(int argc, char *argv[])
 	//warnx("mixed %d outputs (max %d), values:", mixed, output_max);
 	for (unsigned i = 0; i < mixed; i++) {
 
-		warnx("pre-arm:\t %d: out: %8.4f, servo: %d", i, (double)outputs[i], (int)r_page_servos[i]);
+		fprintf(stderr, "pre-arm:\t %d: out: %8.4f, servo: %d \n", i, (double)outputs[i], (int)r_page_servos[i]);
 
 		if (i != actuator_controls_s::INDEX_THROTTLE) {
 			if (r_page_servos[i] < r_page_servo_control_min[i]) {
@@ -250,7 +250,7 @@ int test_mixer(int argc, char *argv[])
 		//warnx("mixed %d outputs (max %d), values:", mixed, output_max);
 		for (unsigned i = 0; i < mixed; i++) {
 
-			warnx("ramp:\t %d: out: %8.4f, servo: %d", i, (double)outputs[i], (int)r_page_servos[i]);
+			fprintf(stderr, "ramp:\t %d: out: %8.4f, servo: %d \n", i, (double)outputs[i], (int)r_page_servos[i]);
 
 			/* check mixed outputs to be zero during init phase */
 			if (hrt_elapsed_time(&starttime) < INIT_TIME_US &&
@@ -298,7 +298,7 @@ int test_mixer(int argc, char *argv[])
 			servo_predicted[i] = 1500 + outputs[i] * (r_page_servo_control_max[i] - r_page_servo_control_min[i]) / 2.0f;
 
 			if (abs(servo_predicted[i] - r_page_servos[i]) > 2) {
-				printf("\t %d: %8.4f predicted: %d, servo: %d\n", i, (double)outputs[i], servo_predicted[i], (int)r_page_servos[i]);
+				fprintf(stderr, "\t %d: %8.4f predicted: %d, servo: %d\n", i, (double)outputs[i], servo_predicted[i], (int)r_page_servos[i]);
 				PX4_ERR("mixer violated predicted value");
 				return 1;
 			}
@@ -323,7 +323,7 @@ int test_mixer(int argc, char *argv[])
 		//warnx("mixed %d outputs (max %d), values:", mixed, output_max);
 		for (unsigned i = 0; i < mixed; i++) {
 
-			warnx("disarmed:\t %d: out: %8.4f, servo: %d", i, (double)outputs[i], (int)r_page_servos[i]);
+			fprintf(stderr, "disarmed:\t %d: out: %8.4f, servo: %d \n", i, (double)outputs[i], (int)r_page_servos[i]);
 
 			/* check mixed outputs to be zero during init phase */
 			if (r_page_servos[i] != r_page_servo_disarmed[i]) {
@@ -365,7 +365,7 @@ int test_mixer(int argc, char *argv[])
 
 			/* check ramp */
 
-			warnx("ramp:\t %d: out: %8.4f, servo: %d", i, (double)outputs[i], (int)r_page_servos[i]);
+			fprintf(stderr, "ramp:\t %d: out: %8.4f, servo: %d \n", i, (double)outputs[i], (int)r_page_servos[i]);
 
 			if (hrt_elapsed_time(&starttime) < RAMP_TIME_US &&
 			    (r_page_servos[i] + 1 <= r_page_servo_disarmed[i] ||
diff --git a/unittests/run_tests.sh b/unittests/run_tests.sh
index 9943fc74c7..979f8c95dd 100755
--- a/unittests/run_tests.sh
+++ b/unittests/run_tests.sh
@@ -9,6 +9,6 @@ set -e
 #./param_test
 ./conversion_test
 ./autodeclination_test
-./mixer_test > /dev/null
+./mixer_test 2> /dev/null
 ./sbus2_test
 ./rc_input_test