+test_expect_success \
+ 'prepare work tree once again' \
+ 'cat ../../COPYING >COPYING &&
+ git-update-cache --add --remove COPYING COPYING.1'
+
+# tree has COPYING. work tree has the same COPYING and COPYING.1,
+# but COPYING is not edited. We say you copy-and-edit COPYING.1;
+# this is only possible because -C mode now reports the unmodified
+# file to the diff-core.
+
+GIT_DIFF_OPTS=--unified=0 git-diff-cache -C $tree |
+sed -e 's/\([0-9][0-9]*\)/#/g' >current
+cat >expected <<\EOF
+diff --git a/COPYING b/COPYING.#
+similarity index #%
+copy from COPYING
+copy to COPYING.#
+--- a/COPYING
++++ b/COPYING.#
+@@ -# +# @@
+- HOWEVER, in order to allow a migration to GPLv# if that seems like
++ However, in order to allow a migration to GPLv# if that seems like
+EOF
+
+test_expect_success \
+ 'validate output from rename/copy detection' \
+ 'diff -u current expected'
+