test_cmp expect actual
'
+test_expect_success 'set up pathological context' '
+ git reset --hard &&
+ test_write_lines a a a a a a a a a a a >a &&
+ git add a &&
+ git commit -m a &&
+ test_write_lines c b a a a a a a a b a a a a >a &&
+ test_write_lines a a a a a a a b a a a a >expected-1 &&
+ test_write_lines b a a a a a a a b a a a a >expected-2 &&
+ # check editing can cope with missing header and deleted context lines
+ # as well as changes to other lines
+ test_write_lines +b " a" >patch
+'
+
+test_expect_failure 'add -p works with pathological context lines' '
+ git reset &&
+ printf "%s\n" n y |
+ git add -p &&
+ git cat-file blob :a >actual &&
+ test_cmp expected-1 actual
+'
+
+test_expect_failure 'add -p patch editing works with pathological context lines' '
+ git reset &&
+ # n q q below is in case edit fails
+ printf "%s\n" e y n q q |
+ git add -p &&
+ git cat-file blob :a >actual &&
+ test_cmp expected-2 actual
+'
+
test_done