diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
index 63b3039243..40615debc4 100755
--- a/t/t7810-grep.sh
+++ b/t/t7810-grep.sh
@@ -1096,11 +1096,6 @@ test_expect_success 'grep -E pattern with grep.patternType=fixed' '
 	test_cmp expected actual
 '
 
-test_config() {
-	git config "$1" "$2" &&
-	test_when_finished "git config --unset $1"
-}
-
 cat >expected <<EOF
 hello.c<RED>:<RESET>int main(int argc, const char **argv)
 hello.c<RED>-<RESET>{