diff --git a/tests/lib/chrome-source.js b/tests/lib/chrome-source.js
new file mode 100644
index 0000000..2be0799
--- /dev/null
+++ b/tests/lib/chrome-source.js
@@ -0,0 +1,53 @@
+/**
+ * Copyright 2022 Google LLC
+ *
+ * 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 test from 'ava';
+import {tmpdir} from 'os';
+import { urlFor, fetchAllTo } from '../../tools/lib/chrome-source.js';
+
+const revision = '23a41c068e35f33df1c3579a3b0b469d4458e6c1';
+const chromePath = 'chrome/common/apps/platform_apps/api';
+const chromePaths = [
+  'tools/json_schema_compiler',
+  'tools/json_schema_compiler/test',
+  'tools/json_comment_eater',
+  'ppapi/generators',
+  'third_party/ply',
+];
+
+test('urlFor', (t) => {
+  // Returns valid url
+  const uf = urlFor(revision, chromePath);
+  t.is(uf.startsWith('https://'), true);
+  t.is(uf.includes(revision), true);
+  t.is(uf.endsWith(`${chromePath}.tar.gz`), true);
+});
+
+test('fetchAllTo', async (t) => {
+  let fta;
+  // Returns chrome source tree files for each path
+  fta = await fetchAllTo(tmpdir(), chromePaths, revision);
+  t.is(Array.isArray(fta), true);
+  t.is(fta.length, chromePaths.length);
+
+  // Throws error with invalid arguments
+  // @ts-ignore
+  await t.throwsAsync(() => fetchAllTo(null, chromePaths, revision));
+  // @ts-ignore
+  t.throws(() => fetchAllTo(tmpdir(), null, revision));
+  // @ts-ignore
+  await t.throwsAsync(() => fetchAllTo(tmpdir(), chromePaths, null));
+});
diff --git a/tools/lib/chrome-source.js b/tools/lib/chrome-source.js
index 290da47..75a7743 100644
--- a/tools/lib/chrome-source.js
+++ b/tools/lib/chrome-source.js
@@ -33,7 +33,7 @@ import fetch from 'node-fetch';
  * @param {string} chromePath
  * @return {string}
  */
-function urlFor(revision, chromePath) {
+export function urlFor(revision, chromePath) {
   return `https://chromium.googlesource.com/chromium/src/+archive/${revision}/${chromePath}.tar.gz`;
 }
 
@@ -46,7 +46,7 @@ function urlFor(revision, chromePath) {
  * @param {string} revision revision to fetch
  * @return {Promise<(string[]?)[]>} files written for paths, null for skipped
  */
-export async function fetchAllTo(targetPath, chromePaths, revision) {
+export function fetchAllTo(targetPath, chromePaths, revision) {
   // This removes any trailing "/" from the paths.
   chromePaths = chromePaths.map(chromePath => path.join(chromePath, '.'));