[PATCH v3 28/35] 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 | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/t/t4018-diff-funcname.sh b/t/t4018-diff-funcname.sh
index ca23d156666..ba10d1f5313 100755
--- a/t/t4018-diff-funcname.sh
+++ b/t/t4018-diff-funcname.sh

@@ -130,6 +130,13 @@ test_diff_funcname () {
 		test_cmp expected actual
 	' &&
 
+	test_expect_success "$desc -U9001" '
+		git diff -U9001 "$what" >diff &&
+		last_diff_context_line diff >actual &&
+		echo >blank &&
+		test_cmp blank actual
+	' &&
+
 	test_expect_success "teardown: $desc" '
 		# In case any custom config was set immediately before
 		# the test itself in the test file

-- 
2.30.0.284.gd98b1dd5eaa7