--- a/tests/test-manifest.t	Thu Mar 14 10:58:53 2019 +0000
+++ b/tests/test-manifest.t	Thu Mar 14 09:12:46 2019 +0000
@@ -142,3 +142,9 @@
   id: 1e01206b1d2f72bd55f2a33fa8ccad74144825b7, size 133 bytes
   id: fce2a30dedad1eef4da95ca1dc0004157aa527cf, size 87 bytes
   total cache data size 268 bytes, on-disk 268 bytes
+
+Check cache clearing
+
+  $ hg debugmanifestfulltextcache --clear
+  $ hg debugmanifestfulltextcache
+  cache empty