test-lib: tests skipped by GIT_SKIP_TESTS say so

We used to show "(missing )" next to tests skipped because they are
specified in GIT_SKIP_TESTS.  Use "(GIT_SKIP_TESTS)" instead.

Plus tests that check basic GIT_SKIP_TESTS functions.

Signed-off-by: Ilya Bobyr <ilya.bobyr@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: illia-bobyr

t/t0000-basic.sh

@@ -270,6 +270,69 @@ test_expect_success 'test --verbose-only' '
 	EOF
 '
 
+test_expect_success 'GIT_SKIP_TESTS' "
+	GIT_SKIP_TESTS='git.2' \
+		run_sub_test_lib_test git-skip-tests-basic \
+		'GIT_SKIP_TESTS' <<-\\EOF &&
+	for i in 1 2 3
+	do
+		test_expect_success \"passing test #\$i\" 'true'
+	done
+	test_done
+	EOF
+	check_sub_test_lib_test git-skip-tests-basic <<-\\EOF
+	> ok 1 - passing test #1
+	> ok 2 # skip passing test #2 (GIT_SKIP_TESTS)
+	> ok 3 - passing test #3
+	> # passed all 3 test(s)
+	> 1..3
+	EOF
+"
+
+test_expect_success 'GIT_SKIP_TESTS several tests' "
+	GIT_SKIP_TESTS='git.2 git.5' \
+		run_sub_test_lib_test git-skip-tests-several \
+		'GIT_SKIP_TESTS several tests' <<-\\EOF &&
+	for i in 1 2 3 4 5 6
+	do
+		test_expect_success \"passing test #\$i\" 'true'
+	done
+	test_done
+	EOF
+	check_sub_test_lib_test git-skip-tests-several <<-\\EOF
+	> ok 1 - passing test #1
+	> ok 2 # skip passing test #2 (GIT_SKIP_TESTS)
+	> ok 3 - passing test #3
+	> ok 4 - passing test #4
+	> ok 5 # skip passing test #5 (GIT_SKIP_TESTS)
+	> ok 6 - passing test #6
+	> # passed all 6 test(s)
+	> 1..6
+	EOF
+"
+
+test_expect_success 'GIT_SKIP_TESTS sh pattern' "
+	GIT_SKIP_TESTS='git.[2-5]' \
+		run_sub_test_lib_test git-skip-tests-sh-pattern \
+		'GIT_SKIP_TESTS sh pattern' <<-\\EOF &&
+	for i in 1 2 3 4 5 6
+	do
+		test_expect_success \"passing test #\$i\" 'true'
+	done
+	test_done
+	EOF
+	check_sub_test_lib_test git-skip-tests-sh-pattern <<-\\EOF
+	> ok 1 - passing test #1
+	> ok 2 # skip passing test #2 (GIT_SKIP_TESTS)
+	> ok 3 # skip passing test #3 (GIT_SKIP_TESTS)
+	> ok 4 # skip passing test #4 (GIT_SKIP_TESTS)
+	> ok 5 # skip passing test #5 (GIT_SKIP_TESTS)
+	> ok 6 - passing test #6
+	> # passed all 6 test(s)
+	> 1..6
+	EOF
+"
+
 test_set_prereq HAVEIT
 haveit=no
 test_expect_success HAVEIT 'test runs if prerequisite is satisfied' '

t/test-lib.sh

@@ -452,25 +452,28 @@ test_finish_ () {
 
 test_skip () {
 	to_skip=
+	skipped_reason=
 	if match_pattern_list $this_test.$test_count $GIT_SKIP_TESTS
 	then
 		to_skip=t
+		skipped_reason="GIT_SKIP_TESTS"
 	fi
 	if test -z "$to_skip" && test -n "$test_prereq" &&
 	   ! test_have_prereq "$test_prereq"
 	then
 		to_skip=t
-	fi
-	case "$to_skip" in
-	t)
+
 		of_prereq=
 		if test "$missing_prereq" != "$test_prereq"
 		then
 			of_prereq=" of $test_prereq"
 		fi
-
+		skipped_reason="missing $missing_prereq${of_prereq}"
+	fi
+	case "$to_skip" in
+	t)
 		say_color skip >&3 "skipping test: $@"
-		say_color skip "ok $test_count # skip $1 (missing $missing_prereq${of_prereq})"
+		say_color skip "ok $test_count # skip $1 ($skipped_reason)"
 		: true
 		;;
 	*)