diff --git a/.astyleignore b/.astyleignore
index 8583ce89ca..59436acfdf 100644
--- a/.astyleignore
+++ b/.astyleignore
@@ -14,5 +14,6 @@ hal/storage_abstraction
 FEATURE_NANOSTACK/coap-service
 FEATURE_NANOSTACK/sal-stack-nanostack
 rtos/TARGET_CORTEX/rtx5
+TESTS/mbed_hal/trng/pithy
 targets
 tools