diff --git a/services/surfaceflinger/tests/Credentials_test.cpp b/services/surfaceflinger/tests/Credentials_test.cpp
index 3b6a51a..c1ef48e 100644
--- a/services/surfaceflinger/tests/Credentials_test.cpp
+++ b/services/surfaceflinger/tests/Credentials_test.cpp
@@ -358,8 +358,13 @@
                 .apply();
     }
 
-    // Called from non privileged process
-    Transaction().setTrustedOverlay(surfaceControl, true);
+    // Attempt to set a trusted overlay from a non-privileged process. This should fail silently.
+    {
+        UIDFaker f{AID_BIN};
+        Transaction().setTrustedOverlay(surfaceControl, true).apply(/*synchronous=*/true);
+    }
+
+    // Verify that the layer was not made a trusted overlay.
     {
         UIDFaker f(AID_SYSTEM);
         auto windowIsPresentAndNotTrusted = [&](const std::vector<WindowInfo>& windowInfos) {
@@ -370,12 +375,14 @@
             }
             return !foundWindowInfo->inputConfig.test(WindowInfo::InputConfig::TRUSTED_OVERLAY);
         };
-        windowInfosListenerUtils.waitForWindowInfosPredicate(windowIsPresentAndNotTrusted);
+        ASSERT_TRUE(
+                windowInfosListenerUtils.waitForWindowInfosPredicate(windowIsPresentAndNotTrusted));
     }
 
+    // Verify that privileged processes are able to set trusted overlays.
     {
         UIDFaker f(AID_SYSTEM);
-        Transaction().setTrustedOverlay(surfaceControl, true);
+        Transaction().setTrustedOverlay(surfaceControl, true).apply(/*synchronous=*/true);
         auto windowIsPresentAndTrusted = [&](const std::vector<WindowInfo>& windowInfos) {
             auto foundWindowInfo =
                     WindowInfosListenerUtils::findMatchingWindowInfo(windowInfo, windowInfos);
@@ -384,7 +391,8 @@
             }
             return foundWindowInfo->inputConfig.test(WindowInfo::InputConfig::TRUSTED_OVERLAY);
         };
-        windowInfosListenerUtils.waitForWindowInfosPredicate(windowIsPresentAndTrusted);
+        ASSERT_TRUE(
+                windowInfosListenerUtils.waitForWindowInfosPredicate(windowIsPresentAndTrusted));
     }
 }