Bug 1303484 - browser_device_modal_submit.js | unexpected number of devices; r=jryans

- Added `addDeviceForTest` that removes automatically the device added at the
  end of the test.
- Improved `switchDevice` with more assertions.

MozReview-Commit-ID: D1BJozD65uj

devtools/client/responsive.html/test/browser/browser_device_change.js

@@ -13,8 +13,6 @@ const DEFAULT_UA = Cc["@mozilla.org/network/protocol;1?name=http"]
 
 const Types = require("devtools/client/responsive.html/types");
 
-const { addDevice, removeDevice } = require("devtools/client/shared/devices");
-
 const testDevice = {
   "name": "Fake Phone RDM Test",
   "width": 320,
@@ -28,7 +26,7 @@ const testDevice = {
 };
 
 // Add the new device to the list
-addDevice(testDevice);
+addDeviceForTest(testDevice);
 
 addRDMTask(TEST_URL, function* ({ ui, manager }) {
   let { store } = ui.toolWindow;
@@ -65,9 +63,6 @@ addRDMTask(TEST_URL, function* ({ ui, manager }) {
   yield testUserAgent(ui, DEFAULT_UA);
   yield testDevicePixelRatio(ui, 1);
   yield testTouchEventsOverride(ui, false);
-
-  ok(removeDevice(testDevice),
-    "Test Device properly removed.");
 });
 
 function testViewportDimensions(ui, w, h) {

devtools/client/responsive.html/test/browser/browser_device_modal_submit.js

@@ -4,7 +4,7 @@ http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 
 // Test submitting display device changes on the device modal
-const { getDevices, addDevice } = require("devtools/client/shared/devices");
+const { getDevices } = require("devtools/client/shared/devices");
 
 const addedDevice = {
   "name": "Fake Phone RDM Test",
@@ -107,7 +107,7 @@ addRDMTask(TEST_URL, function* ({ ui }) {
     checkedVal + " is unchecked in the device modal.");
 
   // Let's add a dummy device to simulate featured flag changes for next test
-  addDevice(addedDevice);
+  addDeviceForTest(addedDevice);
 });
 
 addRDMTask(TEST_URL, function* ({ ui }) {

devtools/client/responsive.html/test/browser/head.js

@@ -37,6 +37,7 @@ const OPEN_DEVICE_MODAL_VALUE = "OPEN_DEVICE_MODAL";
 const { _loadPreferredDevices } = require("devtools/client/responsive.html/actions/devices");
 const { getOwnerWindow } = require("sdk/tabs/utils");
 const asyncStorage = require("devtools/shared/async-storage");
+const { addDevice, removeDevice } = require("devtools/client/shared/devices");
 
 SimpleTest.requestCompleteLog();
 SimpleTest.waitForExplicitFinish();
@@ -229,9 +230,14 @@ function openDeviceModal(ui) {
     "The device modal is displayed.");
 }
 
-function switchDevice({ toolWindow }, name) {
+function switchDevice({ toolWindow }, value) {
   return new Promise(resolve => {
-    let select = toolWindow.document.querySelector(".viewport-device-selector");
+    let selector = ".viewport-device-selector";
+    let select = toolWindow.document.querySelector(selector);
+    isnot(select, null, `selector "${selector}" should match an existing element.`);
+
+    let option = [...select.options].find(o => o.value === String(value));
+    isnot(option, undefined, `value "${value}" should match an existing option.`);
 
     let event = new toolWindow.UIEvent("change", {
       view: toolWindow,
@@ -239,13 +245,13 @@ function switchDevice({ toolWindow }, name) {
       cancelable: true
     });
 
-    select.addEventListener("change", function onChange() {
-      is(select.value, name, "Device should be selected");
-      select.removeEventListener("change", onChange);
+    select.addEventListener("change", () => {
+      is(select.value, value,
+        `Select's option with value "${value}" should be selected.`);
       resolve();
-    });
+    }, { once: true });
 
-    select.value = name;
+    select.value = value;
     select.dispatchEvent(event);
   });
 }
@@ -312,3 +318,13 @@ function forward(browser) {
   browser.goForward();
   return shown;
 }
+
+function addDeviceForTest(device) {
+  info(`Adding Test Device "${device.name}" to the list.`);
+  addDevice(device);
+
+  registerCleanupFunction(() => {
+    // Note that assertions in cleanup functions are not displayed unless they failed.
+    ok(removeDevice(device), `Removed Test Device "${device.name}" from the list.`);
+  });
+}