t1300: add tests for missing keys

There are several tests in t1300-config.sh that validate failing
invocations of "git config".  However, there are no tests that check
what happens when "git config" is asked to retrieve a value for a
missing key.

Add tests that check this for various combinations of "<section>.<key>"
and "<section>.<subsection>.<key>".

Signed-off-by: Andrei Rybak <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: rybak

t/t1300-config.sh

@@ -98,6 +98,23 @@ test_expect_success 'subsections are not canonicalized by git-config' '
 	test_cmp_config two section.SubSection.key
 '
 
+test_missing_key () {
+	local key="$1" &&
+	local title="$2" &&
+	test_expect_success "value for $title is not printed" '
+		test_must_fail git config "$key" >out 2>err &&
+		test_must_be_empty out &&
+		test_must_be_empty err
+	'
+}
+
+test_missing_key 'missingsection.missingkey' 'missing section and missing key'
+test_missing_key 'missingsection.penguin' 'missing section and existing key'
+test_missing_key 'section.missingkey' 'existing section and missing key'
+test_missing_key 'section.MissingSubSection.missingkey' 'missing subsection and missing key'
+test_missing_key 'section.SubSection.missingkey' 'existing subsection and missing key'
+test_missing_key 'section.MissingSubSection.key' 'missing subsection and existing key'
+
 cat > .git/config <<\EOF
 [alpha]
 bar = foo