diff --git a/mercurial/debugcommands.py b/mercurial/debugcommands.py
--- a/mercurial/debugcommands.py
+++ b/mercurial/debugcommands.py
@@ -1486,7 +1486,7 @@ def debugmanifestfulltextcache(ui, repo,
             manifest.read()  # stores revisision in cache too
 
         if not len(cache):
-            ui.write(_('Cache empty'))
+            ui.write(_('cache empty\n'))
         else:
             ui.write(
                 _('Cache contains %d manifest entries, in order of most to '
diff --git a/tests/test-manifest.t b/tests/test-manifest.t
--- a/tests/test-manifest.t
+++ b/tests/test-manifest.t
@@ -93,3 +93,17 @@ The next two calls are expected to abort
   $ hg manifest -r tip tip
   abort: please specify just one revision
   [255]
+
+Testing the manifest full text cache utility
+--------------------------------------------
+
+Reminder of the manifest log content
+
+  $ hg log --debug | grep 'manifest:'
+  manifest:    1:1e01206b1d2f72bd55f2a33fa8ccad74144825b7
+  manifest:    0:fce2a30dedad1eef4da95ca1dc0004157aa527cf
+
+Showing the content of the caches after the above operations
+
+  $ hg debugmanifestfulltextcache
+  cache empty