diff_cmp expected output
'
+test_expect_success 'setup file' '
+ test_write_lines a "" b "" c >file &&
+ git add file &&
+ test_write_lines a "" d "" c >file
+'
+
+test_expect_success 'setup patch' '
+ SP=" " &&
+ NULL="" &&
+ cat >patch <<-EOF
+ @@ -1,4 +1,4 @@
+ a
+ $NULL
+ -b
+ +f
+ $SP
+ c
+ EOF
+'
+
+test_expect_success 'setup expected' '
+ cat >expected <<-EOF
+ diff --git a/file b/file
+ index b5dd6c9..f910ae9 100644
+ --- a/file
+ +++ b/file
+ @@ -1,5 +1,5 @@
+ a
+ $SP
+ -f
+ +d
+ $SP
+ c
+ EOF
+'
+
+test_expect_success 'edit can strip spaces from empty context lines' '
+ test_write_lines e n q | git add -p 2>error &&
+ test_must_be_empty error &&
+ git diff >output &&
+ diff_cmp expected output
+'
+
test_expect_success 'skip files similarly as commit -a' '
git reset &&
echo file >.gitignore &&
grep "$(printf "\\033")" output
'
+test_expect_success TTY 'diffFilter filters diff' '
+ git reset --hard &&
+
+ echo content >test &&
+ test_config interactive.diffFilter "sed s/^/foo:/" &&
+ printf y | test_terminal git add -p >output 2>&1 &&
+
+ # avoid depending on the exact coloring or content of the prompts,
+ # and just make sure we saw our diff prefixed
+ grep foo:.*content output
+'
+
+test_expect_success TTY 'detect bogus diffFilter output' '
+ git reset --hard &&
+
+ echo content >test &&
+ test_config interactive.diffFilter "echo too-short" &&
+ printf y | test_must_fail test_terminal git add -p
+'
+
test_expect_success 'patch-mode via -i prompts for files' '
git reset --hard &&