diff --git a/tests/src/psa_crypto_helpers.c b/tests/src/psa_crypto_helpers.c
index 1069edd..197fd41 100644
--- a/tests/src/psa_crypto_helpers.c
+++ b/tests/src/psa_crypto_helpers.c
@@ -74,7 +74,12 @@
 
     mbedtls_psa_get_stats(&stats);
 
-    if (stats.volatile_slots > 1) {
+    /* Some volatile slots may be used for internal purposes. Generally
+     * we'll have exactly MBEDTLS_TEST_PSA_INTERNAL_KEYS at this point,
+     * but in some cases we might have less, e.g. if a code path calls
+     * PSA_DONE more than once, or if there has only been a partial or
+     * failed initialization. */
+    if (stats.volatile_slots > MBEDTLS_TEST_PSA_INTERNAL_KEYS) {
         return "A volatile slot has not been closed properly.";
     }
     if (stats.persistent_slots != 0) {