diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index a8f36745c..3574b9842 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -1002,10 +1002,11 @@ psa_status_t psa_wipe_key_slot( psa_key_slot_t *slot )
 
    /*
     * As the return error code may not be handled in case of multiple errors,
-    * do our best to report an unexpected lock counter: if available call
-    * MBEDTLS_TEST_HOOK_TEST_ASSERT that may terminate execution (if called as
-    * part of the execution of a test suite this will stop the test suite
-    * execution).
+    * do our best to report an unexpected lock counter. Assert with
+    * MBEDTLS_TEST_HOOK_TEST_ASSERT that the lock counter is equal to one:
+    * if the MBEDTLS_TEST_HOOKS configuration option is enabled and the
+    * function is called as part of the execution of a test suite, the
+    * execution of the test suite is stopped in error if the assertion fails.
     */
     if( slot->lock_count != 1 )
     {
diff --git a/library/psa_crypto_slot_management.c b/library/psa_crypto_slot_management.c
index 49e6b873b..a5c43b1b2 100644
--- a/library/psa_crypto_slot_management.c
+++ b/library/psa_crypto_slot_management.c
@@ -414,10 +414,11 @@ psa_status_t psa_unlock_key_slot( psa_key_slot_t *slot )
 
    /*
     * As the return error code may not be handled in case of multiple errors,
-    * do our best to report if the lock counter is equal to zero: if available
-    * call MBEDTLS_TEST_HOOK_TEST_ASSERT that may terminate execution (if called
-    * as part of the execution of a unit test suite this will stop the test
-    * suite execution).
+    * do our best to report if the lock counter is equal to zero. Assert with
+    * MBEDTLS_TEST_HOOK_TEST_ASSERT that the lock counter is strictly greater
+    * than zero: if the MBEDTLS_TEST_HOOKS configuration option is enabled and
+    * the function is called as part of the execution of a test suite, the
+    * execution of the test suite is stopped in error if the assertion fails.
     */
     MBEDTLS_TEST_HOOK_TEST_ASSERT( slot->lock_count > 0 );
     return( PSA_ERROR_CORRUPTION_DETECTED );