repoview: add a test to track operation not supposed to trigger filtering

This test will be useful to confirm we removed filtering trigger and to prevent
it to come back without us noticing.

Differential Revision: https://phab.mercurial-scm.org/D7479

tests/test-repo-filters-tiptoe.t

@@ -0,0 +1,53 b''
+===================================
+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