Re: [PATCH v3 20/35] userdiff tests: assert that new built-in drivers have tests

Add an assertion to the userdiff test framework to check that
everything except a narrow whitelist of existing built-in patterns has
tests.

Since this test framework was added we've added new patterns without
any tests. Let's make it obvious in the future in the diff for such
patches that they should have those tests.

For anything with tests we can skip the "does the pattern compile?"
test, as the actual tests will check that for us.

Signed-off-by: Ævar Arnfjörð Bjarmason <redacted>
---
 t/t4018-diff-funcname.sh | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/t/t4018-diff-funcname.sh b/t/t4018-diff-funcname.sh
index b80546b4d7f..a3058fda130 100755
--- a/t/t4018-diff-funcname.sh
+++ b/t/t4018-diff-funcname.sh

@@ -15,6 +15,19 @@ test_expect_success 'setup' '
 	sort <builtin-drivers >builtin-drivers.sorted &&
 	test_cmp builtin-drivers.sorted builtin-drivers &&
 
+	# Do not add anything to this list. New built-in drivers should have
+	# tests
+	cat >drivers-no-tests <<-\EOF &&
+	ada
+	bibtex
+	csharp
+	html
+	objc
+	pascal
+	ruby
+	tex
+	EOF
+
 	# for regexp compilation tests
 	echo A >A.java &&
 	echo B >B.java

@@ -22,7 +35,12 @@ test_expect_success 'setup' '
 
 for p in $(cat builtin-drivers)
 do
-	test_expect_success "builtin $p pattern compiles" '
+	P=$(echo $p | tr 'a-z' 'A-Z')
+	if grep -q $p drivers-no-tests
+	then
+		test_set_prereq NO_TEST_FOR_DRIVER_$P
+	fi
+	test_expect_success NO_TEST_FOR_DRIVER_$P "builtin $p pattern compiles" '
 		echo "*.java diff=$p" >.gitattributes &&
 		test_expect_code 1 git diff --no-index \
 			A.java B.java 2>msg &&

@@ -119,11 +137,17 @@ test_diff_funcname () {
 	'
 }
 
+>drivers-had-no-tests
 for what in $diffpatterns
 do
 	test="$TEST_DIRECTORY/t4018/$what.sh"
 	if ! test -e "$test"
 	then
+		git -C t4018 ls-files ':!*.sh' "$what*" >other-tests &&
+		if ! test -s other-tests
+		then
+			echo $what >>drivers-had-no-tests
+		fi
 		continue
 	fi &&
 

@@ -135,4 +159,8 @@ do
 	. "$test"
 done
 
+test_expect_success 'we should not have new built-in drivers without tests' '
+	test_cmp drivers-no-tests drivers-had-no-tests
+'
+
 test_done