New test helper to purge persistent key from memory

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>

tests/include/test/psa_crypto_helpers.h

@@ -43,6 +43,11 @@ int mbedtls_test_uses_key_id( mbedtls_svc_key_id_t key_id );
  */
 void mbedtls_test_psa_purge_key_storage( void );
 
+/** Purge the in-memory cache of persistent keys recorded with
+ * #TEST_USES_KEY_ID.
+ */
+void mbedtls_test_psa_purge_key_cache( void );
+
 /** \def TEST_USES_KEY_ID
  *
  * Call this macro in a test function before potentially creating a

tests/src/psa_crypto_helpers.c

@@ -63,6 +63,14 @@ void mbedtls_test_psa_purge_key_storage( void )
         psa_destroy_persistent_key( key_ids_used_in_test[i] );
     num_key_ids_used = 0;
 }
+
+void mbedtls_test_psa_purge_key_cache( void )
+{
+    size_t i;
+    for( i = 0; i < num_key_ids_used; i++ )
+        psa_purge_key( key_ids_used_in_test[i] );
+}
+
 #endif /* MBEDTLS_PSA_CRYPTO_STORAGE_C */
 
 const char *mbedtls_test_helper_is_psa_leaking( void )

tests/suites/test_suite_psa_crypto_slot_management.function

@@ -86,6 +86,7 @@ static int invalidate_psa( invalidate_method_t invalidate_method )
         case INVALIDATE_BY_DESTROYING_WITH_SHUTDOWN:
         case INVALIDATE_BY_PURGING_WITH_SHUTDOWN:
             /* All keys must have been closed. */
+            mbedtls_test_psa_purge_key_cache( );
             PSA_DONE( );
             break;
         case INVALIDATE_BY_SHUTDOWN: