[PATCH 6 of 8 "] manifestcache: clear the cache before testing the debug command

[Pierre-Yves David]

# HG changeset patch
# User Pierre-Yves David <pierre-yves.david at octobus.net>
# Date 1552554775 0
#      Thu Mar 14 09:12:55 2019 +0000
# Node ID 81ba24a2f24106d17e0d865d4973a6228b6106a4
# Parent  fe4fb6f5891c9990e4cdfe22919a8f4d64f3bcf5
# EXP-Topic manifestcache
# Available At https://bitbucket.org/octobus/mercurial-devel/
#              hg pull https://bitbucket.org/octobus/mercurial-devel/ -r 81ba24a2f241
manifestcache: clear the cache before testing the debug command

Right now the cache is empty before this section of the test. However, we are
about to improve the persistence of the cache (putting it under `wllock`,
intead of `lock`). So we install the cleanup before.

diff --git a/tests/test-manifest.t b/tests/test-manifest.t
--- a/tests/test-manifest.t
+++ b/tests/test-manifest.t
@@ -108,6 +108,10 @@ Showing the content of the caches after 
   $ hg debugmanifestfulltextcache
   cache empty
 
+(Clearing the cache in case of any content)
+
+  $ hg debugmanifestfulltextcache --clear
+
 Adding a new persistent entry in the cache
 
   $ hg debugmanifestfulltextcache --add 1e01206b1d2f72bd55f2a33fa8ccad74144825b7