[PATCH 20/20] userdiff tests: assert empty hunk header context on -U<large>

Assert the existing behavior that under -U<large> we'll show no hunk
header context, where <large> takes us past the potential hunk header
we'd have extracted. I'm just picking a number over nine thousand as a
really large number we're unlikely to exceed in these tests.

Signed-off-by: Ævar Arnfjörð Bjarmason <redacted>
---
 t/t4018-diff-funcname.sh | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/t/t4018-diff-funcname.sh b/t/t4018-diff-funcname.sh
index 94026b8296..bd81974dab 100755
--- a/t/t4018-diff-funcname.sh
+++ b/t/t4018-diff-funcname.sh

@@ -103,6 +103,14 @@ test_diff_funcname () {
 		tail -n 1 actual.lines >actual &&
 		test_cmp expected actual
 	'
+
+	test_expect_success "$desc -U9001 (accumulated)" '
+		git diff -U9001 "$what".acc >diff &&
+		last_diff_context_line diff >actual.lines &&
+		tail -n 1 actual.lines >actual &&
+		echo >blank &&
+		test_cmp blank actual
+	'
 }
 
 for what in $diffpatterns

-- 
2.30.0.284.gd98b1dd5eaa7