test-casecollision.t: add test for case changing rename

tests/test-casecollision.t

@@ -1,34 +1,40 b''
 run only on case-sensitive filesystems
 
   $ "$TESTDIR/hghave" no-icasefs || exit 80
 
 test file addition with colliding case
 
   $ hg init repo1
   $ cd repo1
   $ echo a > a
   $ echo A > A
   $ hg add a
   $ hg st
   A a
   ? A
   $ hg add --config ui.portablefilenames=abort A
   abort: possible case-folding collision for A
   [255]
   $ hg st
   A a
   ? A
   $ hg add A
   warning: possible case-folding collision for A
   $ hg st
   A A
   A a
   $ hg forget A
   $ hg st
   A a
   ? A
   $ hg add --config ui.portablefilenames=no A
   $ hg st
   A A
   A a
+
+case changing rename must not warn or abort
+
+  $ echo c > c
+  $ hg ci -qAmx
+  $ hg mv c C
   $ cd ..