builtin/submodule--helper: factor out submodule updating

diff --git a/t/t4020-diff-external.sh b/t/t4020-diff-external.sh
index 49d3f54b298c6519cf83dd59a3886fed9bdf4d96..e009826fcbe5a893df748a47d162e010b95d758b 100755 (executable)
--- a/t/t4020-diff-external.sh
+++ b/t/t4020-diff-external.sh
@@ -13,6 +13,8 @@ test_expect_success setup '
 
        test_tick &&
        echo second >file &&
+       before=$(git hash-object file) &&
+       before=$(git rev-parse --short $before) &&
        git add file &&
        git commit -m second &&
 
@@ -180,9 +182,13 @@ test_expect_success 'no diff with -diff' '
 echo NULZbetweenZwords | perl -pe 'y/Z/\000/' > file
 
 test_expect_success 'force diff with "diff"' '
+       after=$(git hash-object file) &&
+       after=$(git rev-parse --short $after) &&
        echo >.gitattributes "file diff" &&
        git diff >actual &&
-       test_cmp "$TEST_DIRECTORY"/t4020/diff.NUL actual
+       sed -e "s/^index .*/index $before..$after 100644/" \
+               "$TEST_DIRECTORY"/t4020/diff.NUL >expected-diff &&
+       test_cmp expected-diff actual
 '
 
 test_expect_success 'GIT_EXTERNAL_DIFF with more than one changed files' '
@@ -237,7 +243,7 @@ test_expect_success 'diff --cached' '
        git update-index --assume-unchanged file &&
        echo second >file &&
        git diff --cached >actual &&
-       test_cmp "$TEST_DIRECTORY"/t4020/diff.NUL actual
+       test_cmp expected-diff actual
 '
 
 test_expect_success 'clean up crlf leftovers' '