diff --git a/static_src/shared/math.test.js b/static_src/shared/math.test.js
new file mode 100644
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--- /dev/null
+++ b/static_src/shared/math.test.js
@@ -0,0 +1,22 @@
+// 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.
+
+import {assert} from 'chai';
+import {linearRegression} from './math.js';
+
+describe('linearRegression', () => {
+  it('calculate slope and intercept using formula', () => {
+    const values = [0, 1, 2, 3, 4, 5, 6];
+    const [slope, intercept] = linearRegression(values, 7);
+    assert.equal(slope, 1);
+    assert.equal(intercept, 0);
+  });
+
+  it('calculate slope and intercept using last n data points', () => {
+    const values = [0, 1, 0, 3, 5, 7, 9];
+    const [slope, intercept] = linearRegression(values, 4);
+    assert.equal(slope, 2);
+    assert.equal(intercept, 3);
+  });
+});