diff --git a/t/lib-httpd.sh b/t/lib-httpd.sh
index d3829b8d0a..b8996a373a 100644
--- a/t/lib-httpd.sh
+++ b/t/lib-httpd.sh
@@ -157,8 +157,7 @@ test_http_push_nonff() {
 		grep "^ ! \[rejected\][ ]*$BRANCH -> $BRANCH (non-fast-forward)$" output
 	'
 
-	test_expect_success C_LOCALE_OUTPUT 'non-fast-forward push shows help message' '
-		grep "To prevent you from losing history, non-fast-forward updates were rejected" \
-			output
+	test_expect_success 'non-fast-forward push shows help message' '
+		test_i18ngrep "To prevent you from losing history, non-fast-forward updates were rejected" output
 	'
 }
diff --git a/t/t2019-checkout-ambiguous-ref.sh b/t/t2019-checkout-ambiguous-ref.sh
index cc34e5535b..b99d5192a9 100755
--- a/t/t2019-checkout-ambiguous-ref.sh
+++ b/t/t2019-checkout-ambiguous-ref.sh
@@ -29,9 +29,9 @@ test_expect_success 'checkout chooses branch over tag' '
 	test_cmp expect file
 '
 
-test_expect_success C_LOCALE_OUTPUT 'checkout reports switch to branch' '
-	grep "Switched to branch" stderr &&
-	! grep "^HEAD is now at" stderr
+test_expect_success 'checkout reports switch to branch' '
+	test_i18ngrep "Switched to branch" stderr &&
+	test_i18ngrep ! "^HEAD is now at" stderr
 '
 
 test_expect_success 'checkout vague ref succeeds' '
@@ -51,9 +51,9 @@ test_expect_success VAGUENESS_SUCCESS 'checkout chooses branch over tag' '
 	test_cmp expect file
 '
 
-test_expect_success VAGUENESS_SUCCESS,C_LOCALE_OUTPUT 'checkout reports switch to branch' '
-	grep "Switched to branch" stderr &&
-	! grep "^HEAD is now at" stderr
+test_expect_success VAGUENESS_SUCCESS 'checkout reports switch to branch' '
+	test_i18ngrep "Switched to branch" stderr &&
+	test_i18ngrep ! "^HEAD is now at" stderr
 '
 
 test_done