Adds API tests for listRemovableStorageDevices

chrome/test/data/extensions/api_test/image_writer_private/list_devices/test.js

Index: chrome/test/data/extensions/api_test/image_writer_private/list_devices/test.js
diff --git a/chrome/test/data/extensions/api_test/image_writer_private/list_devices/test.js b/chrome/test/data/extensions/api_test/image_writer_private/list_devices/test.js
new file mode 100644
index 0000000000000000000000000000000000000000..20687a96fe9d9862e0a4d60e56f219afb2585d2c
--- /dev/null
+++ b/chrome/test/data/extensions/api_test/image_writer_private/list_devices/test.js
@@ -0,0 +1,45 @@
+// Copyright 2014 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.
+
+var expectedDevices = [{
+  'vendor': 'Vendor 1',
+  'model': 'Model 1',
+  'capacity': 1 << 20,
+  'storageUnitId': '/test/id/1',
+  }, {
+  'vendor': 'Vendor 2',
+  'model': 'Model 2',
+  'capacity': 1 << 22,
+  'storageUnitId': '/test/id/2',
+  }];
+
+
+function testDeviceList() {
+  chrome.imageWriterPrivate.
+      listRemovableStorageDevices(listRemovableDevicesCallback);
+}
+
+function listRemovableDevicesCallback(deviceList) {
+  deviceList.sort(function (a, b) {
+    if (a.storageUnitId > b.storageUnitId) return 1;
+    if (a.storageUnitId < b.storageUnitId) return -1;
+    return 0;
+  });
+
+  if (deviceList.length == 2) {
+    deviceList.forEach(function (dev, i) {
+      var expected = expectedDevices[i];
+      chrome.test.assertEq(expected.vendor, dev.vendor);
+      chrome.test.assertEq(expected.model, dev.model);
+      chrome.test.assertEq(expected.capacity, dev.capacity);
+      chrome.test.assertEq(expected.storageUnitId, dev.storageUnitId);
+    });
+    chrome.test.succeed();
+    return;
+  }
+
+  chrome.test.fail();
+}
+
+chrome.test.runTests([testDeviceList])

[asargent_no_longer_on_chrome, 2014/05/07 21:31:40]

FYI, I think your test is in danger of completing before your callback ever gets
a chance to fire. You either need to *not* use chrome.test.runTests and only
manually call chrome.test.succeed/chrome.test.fail once, *or* use
chrome.test.runTests along with the helpers to make sure it doesn't early
succeed (it waits for known outstanding callbacks to fire before moving on to
success for each test, but you have to tell it that a callback is outstanding).

The chrome.test framework is a little creaky and could use better documentation.
You can see the source code at
chrome/renderer/resources/extensions/test_custom_bindings.js

The general idea for most tests is:


chrome.test.runTests([

  function myFirstTest() {
    // We use chrome.test.callback here to let the test 
    // framework know that there is an outstanding callback
    // and it should not move on to the next test until the
    // callback has fired. If no assertion fails inside the
    // callback, it will consider the test a success and
    // move on to the next one.
    chrome.foo.someMethodWithACallback(
      42, chrome.test.callback(function(some_args) {
      chrome.test.assertEq(some_args.whatever, 19);
    });
  },


  function mySecondTest() {
    // This demonstrates telling the test framework that
    // we are calling a function with a callback and expect
    // that chrome.runtime.lastError will be set, with a
    // particular value for the error message in
    // chrome.runtime.lastError.message.
    chrome.foo.someMethodWithACallback(
      "whatever", chrome.test.callbackFail("invalid input"));
  }

[Drew Haven, 2014/05/08 00:14:34]

Yeah, I had trouble understanding the framework and looking for documentation. 
My next test involves spawning a window and not just a background page so it can
use the fileSystem API and I'm having trouble getting it all to work.

I went with the chrome.test.callback in this case because I feel like if we have
a test framework I should learn to use it.