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tests/TC052-namecache-miss.md

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+# Test Case: Repeated Negative Lookup Behavior
+
+**Test ID**: TC052-namecache-miss
+**Category**: VFS Integration
+**Priority**: High
+
+## Objective
+
+Verify repeated missing-name lookups consistently return ENOENT and do not
+poison a later positive lookup. This is behavior-level negative-namecache
+coverage, not proof of an internal cache hit.
+
+## Procedure
+
+Mount vfs/vfs-plain.erofs and run:
+
+    ./g3_vfs_probe expect-error stat \
+      /tmp/repo22-g3/mnt/testdir/cache-missing 2
+    ./g3_vfs_probe expect-error stat \
+      /tmp/repo22-g3/mnt/testdir/cache-missing 2
+    ./g3_vfs_probe expect-success stat \
+      /tmp/repo22-g3/mnt/testdir/file.txt
+
+## Expected Results
+
+Both negative syscalls report errno 2 and the positive control succeeds.
+Record the stable behavior honestly, with no latency-based cache assertion,
+then clean the mount and md.