Bug 1726465 - [marionette] Don't wait for initial window when new "moz:windowless" capability is set. r=webdriver-reviewers,jdescottes

Depends on D134276

Differential Revision: https://phabricator.services.mozilla.com/D134277

remote/marionette/driver.js

@@ -423,64 +423,67 @@ GeckoDriver.prototype.newSession = async function(cmd) {
       this._currentSession.capabilities.delete("webSocketUrl");
     }
 
-    // Creating a WebDriver session too early can cause issues with
-    // clients in not being able to find any available window handle.
-    // Also when closing the application while it's still starting up can
-    // cause shutdown hangs. As such Marionette will return a new session
-    // once the initial application window has finished initializing.
-    logger.debug(`Waiting for initial application window`);
-    await Marionette.browserStartupFinished;
-
-    const win = await windowManager.waitForInitialApplicationWindowLoaded();
-
-    if (MarionettePrefs.clickToStart) {
-      Services.prompt.alert(
-        win,
-        "",
-        "Click to start execution of marionette tests"
-      );
-    }
-
-    this.addBrowser(win);
-    this.mainFrame = win;
-
     registerCommandsActor();
     enableEventsActor();
 
-    // Setup observer for modal dialogs
-    this.dialogObserver = new modal.DialogObserver(() => this.curBrowser);
-    this.dialogObserver.add(this.handleModalDialog.bind(this));
+    // Don't wait for the initial window when Marionette is in windowless mode
+    if (!this.currentSession.capabilities.get("moz:windowless")) {
+      // Creating a WebDriver session too early can cause issues with
+      // clients in not being able to find any available window handle.
+      // Also when closing the application while it's still starting up can
+      // cause shutdown hangs. As such Marionette will return a new session
+      // once the initial application window has finished initializing.
+      logger.debug(`Waiting for initial application window`);
+      await Marionette.browserStartupFinished;
 
-    for (let win of windowManager.windows) {
-      const tabBrowser = TabManager.getTabBrowser(win);
+      const appWin = await windowManager.waitForInitialApplicationWindowLoaded();
 
-      if (tabBrowser) {
-        for (const tab of tabBrowser.tabs) {
-          const contentBrowser = TabManager.getBrowserForTab(tab);
-          this.registerBrowser(contentBrowser);
-        }
+      if (MarionettePrefs.clickToStart) {
+        Services.prompt.alert(
+          appWin,
+          "",
+          "Click to start execution of marionette tests"
+        );
       }
 
-      this.registerListenersForWindow(win);
+      this.addBrowser(appWin);
+      this.mainFrame = appWin;
+
+      // Setup observer for modal dialogs
+      this.dialogObserver = new modal.DialogObserver(() => this.curBrowser);
+      this.dialogObserver.add(this.handleModalDialog.bind(this));
+
+      for (let win of windowManager.windows) {
+        const tabBrowser = TabManager.getTabBrowser(win);
+
+        if (tabBrowser) {
+          for (const tab of tabBrowser.tabs) {
+            const contentBrowser = TabManager.getBrowserForTab(tab);
+            this.registerBrowser(contentBrowser);
+          }
+        }
+
+        this.registerListenersForWindow(win);
+      }
+
+      if (this.mainFrame) {
+        this.currentSession.chromeBrowsingContext = this.mainFrame.browsingContext;
+        this.mainFrame.focus();
+      }
+
+      if (this.curBrowser.tab) {
+        const browsingContext = this.curBrowser.contentBrowser.browsingContext;
+        this.currentSession.contentBrowsingContext = browsingContext;
+
+        await waitForInitialNavigationCompleted(browsingContext.webProgress);
+
+        this.curBrowser.contentBrowser.focus();
+      }
+
+      // Check if there is already an open dialog for the selected browser window.
+      this.dialog = modal.findModalDialogs(this.curBrowser);
     }
 
-    if (this.mainFrame) {
-      this.currentSession.chromeBrowsingContext = this.mainFrame.browsingContext;
-      this.mainFrame.focus();
-    }
-
-    if (this.curBrowser.tab) {
-      const browsingContext = this.curBrowser.contentBrowser.browsingContext;
-      this.currentSession.contentBrowsingContext = browsingContext;
-
-      await waitForInitialNavigationCompleted(browsingContext.webProgress);
-
-      this.curBrowser.contentBrowser.focus();
-    }
-
-    // Check if there is already an open dialog for the selected browser window.
-    this.dialog = modal.findModalDialogs(this.curBrowser);
-
     Services.obs.addObserver(this, "browser-delayed-startup-finished");
   } catch (e) {
     throw new error.SessionNotCreatedError(e);

remote/shared/WindowManager.jsm

@@ -270,7 +270,7 @@ class WindowManager {
         resolve(subject);
       },
       {
-        errorMessage: "No applicable application windows found",
+        errorMessage: "No applicable application window found",
       }
     );
   }

remote/shared/webdriver/Capabilities.jsm

@@ -457,6 +457,7 @@ class Capabilities extends Map {
       ],
       ["moz:useNonSpecCompliantPointerOrigin", false],
       ["moz:webdriverClick", true],
+      ["moz:windowless", false],
     ]);
   }
 
@@ -586,6 +587,11 @@ class Capabilities extends Map {
           assert.boolean(v, pprint`Expected ${k} to be boolean, got ${v}`);
           break;
 
+        // Don't set the value because it's only used to return the address
+        // of the Remote Agent's debugger (HTTP server).
+        case "moz:debuggerAddress":
+          continue;
+
         case "moz:useNonSpecCompliantPointerOrigin":
           assert.boolean(v, pprint`Expected ${k} to be boolean, got ${v}`);
           break;
@@ -594,10 +600,9 @@ class Capabilities extends Map {
           assert.boolean(v, pprint`Expected ${k} to be boolean, got ${v}`);
           break;
 
-        // Don't set the value because it's only used to return the address
-        // of the Remote Agent's debugger (HTTP server).
-        case "moz:debuggerAddress":
-          continue;
+        case "moz:windowless":
+          assert.boolean(v, pprint`Expected ${k} to be boolean, got ${v}`);
+          break;
       }
 
       matched.set(k, v);

testing/marionette/harness/marionette_harness/tests/unit/test_capabilities.py

@@ -5,6 +5,8 @@
 from __future__ import absolute_import, print_function
 
 import os
+import sys
+import unittest
 
 from marionette_driver.errors import SessionNotCreatedException
 from marionette_harness import MarionetteTestCase
@@ -103,6 +105,9 @@ class TestCapabilities(MarionetteTestCase):
         self.assertIn("moz:webdriverClick", self.caps)
         self.assertTrue(self.caps["moz:webdriverClick"])
 
+        self.assertIn("moz:windowless", self.caps)
+        self.assertFalse(self.caps["moz:windowless"])
+
     def test_disable_webdriver_click(self):
         self.marionette.delete_session()
         self.marionette.start_session({"moz:webdriverClick": False})
@@ -115,13 +120,20 @@ class TestCapabilities(MarionetteTestCase):
         caps = self.marionette.session_capabilities
         self.assertTrue(caps["moz:useNonSpecCompliantPointerOrigin"])
 
-    def test_we_get_valid_uuid4_when_creating_a_session(self):
+    def test_valid_uuid4_when_creating_a_session(self):
         self.assertNotIn(
             "{",
             self.marionette.session_id,
             "Session ID has {{}} in it: {}".format(self.marionette.session_id),
         )
 
+    @unittest.skipUnless(sys.platform.startswith("darwin"), "Only supported on MacOS")
+    def test_windowless(self):
+        self.marionette.delete_session()
+        self.marionette.start_session({"moz:windowless": True})
+        caps = self.marionette.session_capabilities
+        self.assertTrue(caps["moz:windowless"])
+
 
 class TestCapabilityMatching(MarionetteTestCase):
     def setUp(self):