test "$diff" = ""
'
+test_expect_success PERL 'difftool forwards arguments to diff' '
+ >for-diff &&
+ git add for-diff &&
+ echo changes>for-diff &&
+ git add for-diff &&
+ diff=$(git difftool --cached --no-prompt -- for-diff) &&
+ test "$diff" = "" &&
+ git reset -- for-diff &&
+ rm for-diff
+'
+
test_expect_success PERL 'difftool honors --gui' '
git config merge.tool bogus-tool &&
git config diff.tool bogus-tool &&