test-copy2: add case for moving a missing file

tests/test-copy2.t

@@ -27,6 +27,13 b' should print a warning that this is not '
   A foo
   $ hg commit -m1
 
+moving a missing file
+  $ rm foo
+  $ hg mv foo foo3
+  foo: deleted in working copy
+  foo3 does not exist!
+  $ hg up -qC .
+
 copy --after to a nonexistant target filename
   $ hg cp -A foo dummy
   foo: not recording copy - dummy does not exist