diff --git a/sw/device/lib/testing/aon_timer_testutils.c b/sw/device/lib/testing/aon_timer_testutils.c
index d7ef356..2fc7853 100644
--- a/sw/device/lib/testing/aon_timer_testutils.c
+++ b/sw/device/lib/testing/aon_timer_testutils.c
@@ -22,7 +22,7 @@
   CHECK_DIF_OK(dif_aon_timer_irq_acknowledge(aon_timer,
                                              kDifAonTimerIrqWkupTimerExpired));
 
-  bool is_pending;
+  bool is_pending = true;
   CHECK_DIF_OK(dif_aon_timer_irq_is_pending(
       aon_timer, kDifAonTimerIrqWkupTimerExpired, &is_pending));
   CHECK(!is_pending);