diff --git a/static_src/test/setup.js b/static_src/test/setup.js
new file mode 100644
index 0000000..7907cdd
--- /dev/null
+++ b/static_src/test/setup.js
@@ -0,0 +1,16 @@
+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * @fileoverview Test setup code that defines functionality meant to run
+ * before each test.
+ */
+
+import {resetState, store} from 'reducers/base.js';
+
+Mocha.beforeEach(() => {
+  // We reset the Redux state before each test run to prevent Redux
+  // state changes in previous tests from affecting results.
+  store.dispatch(resetState());
+});
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