diff --git a/plugins/github-issues/src/setupTests.ts b/plugins/github-issues/src/setupTests.ts
index 326d2ed212..2f91bcb7b3 100644
--- a/plugins/github-issues/src/setupTests.ts
+++ b/plugins/github-issues/src/setupTests.ts
@@ -13,4 +13,8 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 import '@testing-library/jest-dom';
+import { Settings } from 'luxon';
+
+Settings.defaultLocale = 'en';
diff --git a/plugins/home/src/setupTests.ts b/plugins/home/src/setupTests.ts
index 7435872609..d56608cdc8 100644
--- a/plugins/home/src/setupTests.ts
+++ b/plugins/home/src/setupTests.ts
@@ -13,4 +13,8 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 import '@testing-library/jest-dom';
+import { Settings } from 'luxon';
+
+Settings.defaultLocale = 'en';
diff --git a/plugins/kubernetes-react/src/setupTests.ts b/plugins/kubernetes-react/src/setupTests.ts
index 865308e634..609118cd07 100644
--- a/plugins/kubernetes-react/src/setupTests.ts
+++ b/plugins/kubernetes-react/src/setupTests.ts
@@ -13,4 +13,8 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 import '@testing-library/jest-dom';
+import { Settings } from 'luxon';
+
+Settings.defaultLocale = 'en';
diff --git a/plugins/scaffolder-backend/src/setupTests.ts b/plugins/scaffolder-backend/src/setupTests.ts
new file mode 100644
index 0000000000..a494d80f22
--- /dev/null
+++ b/plugins/scaffolder-backend/src/setupTests.ts
@@ -0,0 +1,19 @@
+/*
+ * Copyright 2022 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { Settings } from 'luxon';
+
+Settings.defaultLocale = 'en';