--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test-repo-filters-tiptoe.t	Sun Nov 17 07:11:06 2019 +0100
@@ -0,0 +1,53 @@
+===================================
+Test repository filtering avoidance
+===================================
+
+This test file is a bit special as he does not check feature, but performance related internal code path.
+
+Right now, filtering a repository comes with a cost that might be significant.
+Until this get better, ther are various operation that try hard not to trigger
+a filtering computation. This test file make sure we don't reintroduce code that trigger the filtering for these operation:
+
+Setup
+-----
+  $ hg init test-repo
+  $ cd test-repo
+  $ echo "some line" > z
+  $ echo a > a
+  $ hg commit -Am a
+  adding a
+  adding z
+  $ echo "in a" >> z
+  $ echo b > b
+  $ hg commit -Am b
+  adding b
+  $ echo "file" >> z
+  $ echo c > c
+  $ hg commit -Am c
+  adding c
+  $ hg rm a
+  $ echo c1 > c
+  $ hg add c
+  c already tracked!
+  $ echo d > d
+  $ hg add d
+  $ rm b
+
+  $ cat << EOF >> $HGRCPATH
+  > [devel]
+  > debug.repo-filters = yes
+  > [ui]
+  > debug = yes
+  > EOF
+
+
+tests
+-----
+
+Getting the node of `null`
+
+  $ hg init test-repo
+  $ cd test-repo
+  $ hg log -r null -T "{node}\n"
+  debug.filters: computing revision filter for "visible"
+  0000000000000000000000000000000000000000