t6302: skip only signed tags rather than all tests when GPG is missing

The primary purpose of these tests is to check filtering, sorting, and
formatting behavior of git-for-each-ref, so it is unfortunate that the
entire test script is skipped when GPG is not present. Rather than
skipping all tests, let's instead just skip testing against signed tags
when GPG is missing.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t6302-for-each-ref-filter.sh

@@ -5,11 +5,14 @@ test_description='test for-each-refs usage of ref-filter APIs'
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-gpg.sh
 
-if ! test_have_prereq GPG
+test_prepare_expect () {
+	if test_have_prereq GPG
 	then
-	skip_all="skipping for-each-ref tests, GPG not available"
+		cat
-	test_done
+	else
+		sed '/signed/d'
 	fi
+}
 
 test_expect_success 'setup some history and refs' '
 	test_commit one &&
@@ -19,8 +22,11 @@ test_expect_success 'setup some history and refs' '
 	test_commit four &&
 	git tag -m "An annotated tag" annotated-tag &&
 	git tag -m "Annonated doubly" doubly-annotated-tag annotated-tag &&
+	if test_have_prereq GPG
+	then
 		git tag -s -m "A signed tag" signed-tag &&
-	git tag -s -m "Signed doubly" doubly-signed-tag signed-tag &&
+		git tag -s -m "Signed doubly" doubly-signed-tag signed-tag
+	fi &&
 	git checkout master &&
 	git update-ref refs/odd/spot master
 '
@@ -36,7 +42,7 @@ test_expect_success 'filtering with --points-at' '
 '
 
 test_expect_success 'check signed tags with --points-at' '
-	sed -e "s/Z$//" >expect <<-\EOF &&
+	test_prepare_expect <<-\EOF | sed -e "s/Z$//" >expect &&
 	refs/heads/side Z
 	refs/tags/annotated-tag four
 	refs/tags/four Z
@@ -59,7 +65,7 @@ test_expect_success 'filtering with --merged' '
 '
 
 test_expect_success 'filtering with --no-merged' '
-	cat >expect <<-\EOF &&
+	test_prepare_expect >expect <<-\EOF &&
 	refs/heads/side
 	refs/tags/annotated-tag
 	refs/tags/doubly-annotated-tag
@@ -72,7 +78,7 @@ test_expect_success 'filtering with --no-merged' '
 '
 
 test_expect_success 'filtering with --contains' '
-	cat >expect <<-\EOF &&
+	test_prepare_expect >expect <<-\EOF &&
 	refs/heads/master
 	refs/heads/side
 	refs/odd/spot
@@ -93,7 +99,7 @@ test_expect_success '%(color) must fail' '
 '
 
 test_expect_success 'left alignment is default' '
-	cat >expect <<-\EOF &&
+	test_prepare_expect >expect <<-\EOF &&
 	refname is refs/heads/master  |refs/heads/master
 	refname is refs/heads/side    |refs/heads/side
 	refname is refs/odd/spot      |refs/odd/spot
@@ -111,7 +117,7 @@ test_expect_success 'left alignment is default' '
 '
 
 test_expect_success 'middle alignment' '
-	cat >expect <<-\EOF &&
+	test_prepare_expect >expect <<-\EOF &&
 	| refname is refs/heads/master |refs/heads/master
 	|  refname is refs/heads/side  |refs/heads/side
 	|   refname is refs/odd/spot   |refs/odd/spot
@@ -129,7 +135,7 @@ test_expect_success 'middle alignment' '
 '
 
 test_expect_success 'right alignment' '
-	cat >expect <<-\EOF &&
+	test_prepare_expect >expect <<-\EOF &&
 	|  refname is refs/heads/master|refs/heads/master
 	|    refname is refs/heads/side|refs/heads/side
 	|      refname is refs/odd/spot|refs/odd/spot
@@ -146,7 +152,7 @@ test_expect_success 'right alignment' '
 	test_cmp expect actual
 '
 
-cat >expect <<-\EOF
+test_prepare_expect >expect <<-\EOF
 |       refname is refs/heads/master       |refs/heads/master
 |        refname is refs/heads/side        |refs/heads/side
 |         refname is refs/odd/spot         |refs/odd/spot
@@ -193,7 +199,7 @@ EOF
 # Individual atoms inside %(align:...) and %(end) must not be quoted.
 
 test_expect_success 'alignment with format quote' "
-	cat >expect <<-\EOF &&
+	test_prepare_expect >expect <<-\EOF &&
 	|'      '\''master| A U Thor'\''      '|
 	|'       '\''side| A U Thor'\''       '|
 	|'     '\''odd/spot| A U Thor'\''     '|
@@ -211,7 +217,7 @@ test_expect_success 'alignment with format quote' "
 "
 
 test_expect_success 'nested alignment with quote formatting' "
-	cat >expect <<-\EOF &&
+	test_prepare_expect >expect <<-\EOF &&
 	|'         master               '|
 	|'           side               '|
 	|'       odd/spot               '|
@@ -229,7 +235,7 @@ test_expect_success 'nested alignment with quote formatting' "
 "
 
 test_expect_success 'check `%(contents:lines=1)`' '
-	cat >expect <<-\EOF &&
+	test_prepare_expect >expect <<-\EOF &&
 	master |three
 	side |four
 	odd/spot |three
@@ -247,7 +253,7 @@ test_expect_success 'check `%(contents:lines=1)`' '
 '
 
 test_expect_success 'check `%(contents:lines=0)`' '
-	cat >expect <<-\EOF &&
+	test_prepare_expect >expect <<-\EOF &&
 	master |
 	side |
 	odd/spot |
@@ -265,7 +271,7 @@ test_expect_success 'check `%(contents:lines=0)`' '
 '
 
 test_expect_success 'check `%(contents:lines=99999)`' '
-	cat >expect <<-\EOF &&
+	test_prepare_expect >expect <<-\EOF &&
 	master |three
 	side |four
 	odd/spot |three