diff --git a/t/t4018-diff-funcname.sh b/t/t4018-diff-funcname.sh
index 4bd2a1c838..9b5db6c77b 100755
--- a/t/t4018-diff-funcname.sh
+++ b/t/t4018-diff-funcname.sh
@@ -93,11 +93,6 @@ sed -e '
 	s/song;/song();/
 ' <Beer.perl >Beer-correct.perl
 
-test_config () {
-	git config "$1" "$2" &&
-	test_when_finished "git config --unset $1"
-}
-
 test_expect_funcname () {
 	lang=${2-java}
 	test_expect_code 1 git diff --no-index -U1 \
diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
index 3021cf251c..b33b7ba6d0 100755
--- a/t/t7810-grep.sh
+++ b/t/t7810-grep.sh
@@ -861,11 +861,6 @@ test_expect_success LIBPCRE 'grep -G -F -E -P pattern' '
 	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>{
diff --git a/t/t7811-grep-open.sh b/t/t7811-grep-open.sh
index a8957782cf..e1951a5cbb 100755
--- a/t/t7811-grep-open.sh
+++ b/t/t7811-grep-open.sh
@@ -125,11 +125,6 @@ test_expect_success 'modified file' '
 	test_cmp empty out
 '
 
-test_config() {
-	git config "$1" "$2" &&
-	test_when_finished "git config --unset $1"
-}
-
 test_expect_success 'copes with color settings' '
 	rm -f actual &&
 	echo grep.h >expect &&