Update TEST_MAPPING

Test: None

Bug: 233924440
Change-Id: Ib46bbb8fb237cd57dd3c57a9394c9c546e435822
diff --git a/TEST_MAPPING b/TEST_MAPPING
index 8029a19..222631c 100644
--- a/TEST_MAPPING
+++ b/TEST_MAPPING
@@ -5,6 +5,11 @@
       "path": "external/rust/crates/base64"
     }
   ],
+  "postsubmit": [
+    {
+      "name": "authfs_device_test_src_lib"
+    }
+  ],
   "presubmit": [
     {
       "name": "authfs_device_test_src_lib"