Ensure tests don't depend on fake devices being added synchronously

third_party/WebKit/LayoutTests/usb/usb.html

Index: third_party/WebKit/LayoutTests/usb/usb.html
diff --git a/third_party/WebKit/LayoutTests/usb/usb.html b/third_party/WebKit/LayoutTests/usb/usb.html
index 82bc0f5af3e447ef55ec6951685715093044c2ab..4a01ac90763273989700e0cf76d003dc67f78995 100644
--- a/third_party/WebKit/LayoutTests/usb/usb.html
+++ b/third_party/WebKit/LayoutTests/usb/usb.html
@@ -7,35 +7,23 @@
 <script>
 'use strict';
 
-// Returns a promise that is resolved when the next USBConnectionEvent of the
-// given type is received.
-function connectionEventPromise(eventType) {
-  return new Promise(resolve => {
-    let eventHandler = e => {
-      assert_true(e instanceof USBConnectionEvent);
-      navigator.usb.removeEventListener(eventType, eventHandler);
-      resolve(e.device);
-    };
-    navigator.usb.addEventListener(eventType, eventHandler);
-  });
-}
-
 usb_test(() => {
-  navigator.usb.test.addFakeDevice(fakeDeviceInit);
-
-  return navigator.usb.getDevices().then(devices => {
-    assert_equals(devices.length, 1);
-    assertDeviceInfoEquals(devices[0], fakeDeviceInit);
+  return getFakeDevice().then(device => {
+    return navigator.usb.getDevices().then(devices => {
+      assert_equals(devices.length, 1);
+      assert_equals(device, devices[0]);
+      assertDeviceInfoEquals(devices[0], fakeDeviceInit);
+    });
   });
-}, 'getDevices returns devices exposed by the DeviceManager service');
+}, 'getDevices returns devices that are connected');
 
 usb_test(() => {
-  navigator.usb.test.addFakeDevice(fakeDeviceInit);
-
-  return navigator.usb.getDevices().then(devicesFirstTime => {
-    assert_equals(devicesFirstTime.length, 1);
-    return navigator.usb.getDevices().then(devicesSecondTime => {
-      assert_array_equals(devicesSecondTime, devicesFirstTime);
+  return getFakeDevice().then(() => {
+    return navigator.usb.getDevices().then(devicesFirstTime => {
+      assert_equals(devicesFirstTime.length, 1);
+      return navigator.usb.getDevices().then(devicesSecondTime => {
+        assert_array_equals(devicesSecondTime, devicesFirstTime);
+      });
     });
   });
 }, 'getDevices returns the same objects for each USB device');
@@ -62,26 +50,29 @@ usb_test(() => {
 }, 'requestDevice rejects when no device is chosen');
 
 usb_test(() => {
-  let guid = navigator.usb.test.addFakeDevice(fakeDeviceInit);
-  navigator.usb.test.chosenDevice = guid;
-
-  return callWithKeyDown(() => navigator.usb.requestDevice({ filters: [] })
-    .then(device => {
-      assertDeviceInfoEquals(device, fakeDeviceInit);
-    })
-  );
+  return getFakeDeviceAndGuid().then(({ device, guid }) => {
+    navigator.usb.test.chosenDevice = guid;
+    return callWithKeyDown(() => {
+      return navigator.usb.requestDevice({ filters: [] }).then(chosenDevice => {

[ortuno, 2017/04/18 00:44:22]

out of topic: Out of curiosity, how do you test the chooser? For web bluetooth
we have a test API that we use to check what happens in the chooser e.g. a new
device is added, a device is removed, etc.

[Reilly Grant (use Gerrit), 2017/04/18 01:27:52]

https://cs.chromium.org/chromium/src/chrome/browser/usb/usb_chooser_controlle...

[ortuno, 2017/04/18 03:04:06]

hmm so for Web Bluetooth we have tests to make sure the right devices appear on
the chooser depending on the filters. Do WebUSB's layout tests have something
similar?

[Reilly Grant (use Gerrit), 2017/04/18 18:21:38]

What devices appear in the chooser isn't visible to layout tests. The filtering
logic is tested in,

https://cs.chromium.org/chromium/src/device/usb/usb_device_filter_unittest.cc

[ortuno, 2017/04/18 21:27:16]

No need to change anything, but why isn't this tested through layout tests? The
algorithm to filter devices is spec'ed and without cross browser tests for the
algorithm there is no way to know all implementations are correct.

+        assert_equals(chosenDevice, device);
+      });
+    });
+  });
 }, 'requestDevice returns the device chosen by the user');
 
 usb_test(() => {
-  let guid = navigator.usb.test.addFakeDevice(fakeDeviceInit);
-  navigator.usb.test.chosenDevice = guid;
-
-  return callWithKeyDown(() => navigator.usb.requestDevice({ filters: [] })
-      .then(device => navigator.usb.getDevices().then(devices => {
-        assert_equals(devices.length, 1);
-        assert_equals(devices[0], device);
-      }))
-  );
+  return getFakeDeviceAndGuid().then(({ device, guid }) => {
+    navigator.usb.test.chosenDevice = guid;
+    return callWithKeyDown(() => {
+      return navigator.usb.requestDevice({ filters: [] }).then(chosenDevice => {
+        assert_equals(chosenDevice, device);
+        return navigator.usb.getDevices().then(devices => {
+          assert_equals(devices.length, 1);
+          assert_equals(devices[0], chosenDevice);
+        });
+      });
+    });
+  });
 }, 'getDevices returns the same object as requestDevice');
 
 usb_test(() => {
@@ -105,34 +96,15 @@ usb_test(() => {
 }, 'filters are sent correctly');
 
 usb_test(() => {
-  let promise = connectionEventPromise('connect');
-  navigator.usb.test.addFakeDevice(fakeDeviceInit);
-
-  return promise.then(device => {
+  return getFakeDevice().then(device => {
     assertDeviceInfoEquals(device, fakeDeviceInit);
     return device.open().then(() => device.close());
   });
 }, 'onconnect event is trigged by adding a device');
 
 usb_test(usb => {
-  let promise = connectionEventPromise('connect');
-  navigator.usb.test.addFakeDevice(fakeDeviceInit);
-
-  return promise
-      .then(device => navigator.usb.getDevices().then(devices => {
-        assert_equals(devices.length, 1);
-        assert_equals(devices[0], device);
-      }));
-}, 'getDevices returns the same object as sent in the onconnect event');
-
-usb_test(usb => {
-  let deviceAdded = connectionEventPromise('connect');
-  let guid = navigator.usb.test.addFakeDevice(fakeDeviceInit);
-
-  return deviceAdded.then(device => {
-    let deviceRemoved = connectionEventPromise('disconnect');
-    navigator.usb.test.removeFakeDevice(guid);
-    return deviceRemoved.then(removedDevice => {
+  return getFakeDeviceAndGuid().then(({ device, guid }) => {
+    return waitForDisconnect(guid).then(removedDevice => {
       assertDeviceInfoEquals(removedDevice, fakeDeviceInit);
       assert_equals(removedDevice, device);
       return removedDevice.open().then(() => {