t4014: more tests about appending s-o-b lines

[bc: Squash the tests from Duy's original unify-appending-sob series.

     Fix test 90 "signoff: some random signoff-alike" and mark as failing.
     Correct behavior should insert a blank line after message body and
     signed-off-by.

     Add two additional tests:

       1. failure to detect non-conforming elements in the footer when last
          line matches committer's s-o-b.
       2. ensure various s-o-b -like elements in the footer are handled as
          conforming. e.g. "Change-id: IXXXX or Bug: 1234"
]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Brandon Casey <bcasey@nvidia.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t4014-format-patch.sh

@@ -963,4 +963,245 @@ test_expect_success 'format patch ignores color.ui' '
 	test_cmp expect actual
 '
 
+append_signoff()
+{
+	C=$(git commit-tree HEAD^^{tree} -p HEAD) &&
+	git format-patch --stdout --signoff $C^..$C >append_signoff.patch &&
+	sed -n -e "1,/^---$/p" append_signoff.patch |
+		egrep -n "^Subject|Sign|^$"
+}
+
+test_expect_success 'signoff: commit with no body' '
+	append_signoff </dev/null >actual &&
+	cat <<\EOF | sed "s/EOL$//" >expected &&
+4:Subject: [PATCH] EOL
+8:
+9:Signed-off-by: C O Mitter <committer@example.com>
+EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'signoff: commit with only subject' '
+	echo subject | append_signoff >actual &&
+	cat >expected <<\EOF &&
+4:Subject: [PATCH] subject
+8:
+9:Signed-off-by: C O Mitter <committer@example.com>
+EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'signoff: commit with only subject that does not end with NL' '
+	printf subject | append_signoff >actual &&
+	cat >expected <<\EOF &&
+4:Subject: [PATCH] subject
+8:
+9:Signed-off-by: C O Mitter <committer@example.com>
+EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'signoff: no existing signoffs' '
+	append_signoff <<\EOF >actual &&
+subject
+
+body
+EOF
+	cat >expected <<\EOF &&
+4:Subject: [PATCH] subject
+8:
+10:
+11:Signed-off-by: C O Mitter <committer@example.com>
+EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'signoff: no existing signoffs and no trailing NL' '
+	printf "subject\n\nbody" | append_signoff >actual &&
+	cat >expected <<\EOF &&
+4:Subject: [PATCH] subject
+8:
+10:
+11:Signed-off-by: C O Mitter <committer@example.com>
+EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'signoff: some random signoff' '
+	append_signoff <<\EOF >actual &&
+subject
+
+body
+
+Signed-off-by: my@house
+EOF
+	cat >expected <<\EOF &&
+4:Subject: [PATCH] subject
+8:
+10:
+11:Signed-off-by: my@house
+12:Signed-off-by: C O Mitter <committer@example.com>
+EOF
+	test_cmp expected actual
+'
+
+test_expect_failure 'signoff: some random signoff-alike' '
+	append_signoff <<\EOF >actual &&
+subject
+
+body
+Fooled-by-me: my@house
+EOF
+	cat >expected <<\EOF &&
+4:Subject: [PATCH] subject
+8:
+11:
+12:Signed-off-by: C O Mitter <committer@example.com>
+EOF
+	test_cmp expected actual
+'
+
+test_expect_failure 'signoff: not really a signoff' '
+	append_signoff <<\EOF >actual &&
+subject
+
+I want to mention about Signed-off-by: here.
+EOF
+	cat >expected <<\EOF &&
+4:Subject: [PATCH] subject
+8:
+9:I want to mention about Signed-off-by: here.
+10:
+11:Signed-off-by: C O Mitter <committer@example.com>
+EOF
+	test_cmp expected actual
+'
+
+test_expect_failure 'signoff: not really a signoff (2)' '
+	append_signoff <<\EOF >actual &&
+subject
+
+My unfortunate
+Signed-off-by: example happens to be wrapped here.
+EOF
+	cat >expected <<\EOF &&
+4:Subject: [PATCH] subject
+8:
+10:Signed-off-by: example happens to be wrapped here.
+11:
+12:Signed-off-by: C O Mitter <committer@example.com>
+EOF
+	test_cmp expected actual
+'
+
+test_expect_failure 'signoff: valid S-o-b paragraph in the middle' '
+	append_signoff <<\EOF >actual &&
+subject
+
+Signed-off-by: my@house
+Signed-off-by: your@house
+
+A lot of houses.
+EOF
+	cat >expected <<\EOF &&
+4:Subject: [PATCH] subject
+8:
+9:Signed-off-by: my@house
+10:Signed-off-by: your@house
+11:
+13:
+14:Signed-off-by: C O Mitter <committer@example.com>
+EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'signoff: the same signoff at the end' '
+	append_signoff <<\EOF >actual &&
+subject
+
+body
+
+Signed-off-by: C O Mitter <committer@example.com>
+EOF
+	cat >expected <<\EOF &&
+4:Subject: [PATCH] subject
+8:
+10:
+11:Signed-off-by: C O Mitter <committer@example.com>
+EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'signoff: the same signoff at the end, no trailing NL' '
+	printf "subject\n\nSigned-off-by: C O Mitter <committer@example.com>" |
+		append_signoff >actual &&
+	cat >expected <<\EOF &&
+4:Subject: [PATCH] subject
+8:
+9:Signed-off-by: C O Mitter <committer@example.com>
+EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'signoff: the same signoff NOT at the end' '
+	append_signoff <<\EOF >actual &&
+subject
+
+body
+
+Signed-off-by: C O Mitter <committer@example.com>
+Signed-off-by: my@house
+EOF
+	cat >expected <<\EOF &&
+4:Subject: [PATCH] subject
+8:
+10:
+11:Signed-off-by: C O Mitter <committer@example.com>
+12:Signed-off-by: my@house
+EOF
+	test_cmp expected actual
+'
+
+test_expect_failure 'signoff: detect garbage in non-conforming footer' '
+	append_signoff <<\EOF >actual &&
+subject
+
+body
+
+Tested-by: my@house
+Some Trash
+Signed-off-by: C O Mitter <committer@example.com>
+EOF
+	cat >expected <<\EOF &&
+4:Subject: [PATCH] subject
+8:
+10:
+13:Signed-off-by: C O Mitter <committer@example.com>
+14:
+15:Signed-off-by: C O Mitter <committer@example.com>
+EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'signoff: footer begins with non-signoff without @ sign' '
+	append_signoff <<\EOF >actual &&
+subject
+
+body
+
+Reviewed-id: Noone
+Tested-by: my@house
+Change-id: Ideadbeef
+Signed-off-by: C O Mitter <committer@example.com>
+Bug: 1234
+EOF
+	cat >expected <<\EOF &&
+4:Subject: [PATCH] subject
+8:
+10:
+14:Signed-off-by: C O Mitter <committer@example.com>
+EOF
+	test_cmp expected actual
+'
+
 test_done