bug 1492499: webdriver: take 22px window border into account on maximizing; r=automatedtester,whimboo

On some systems and window managers, such as macOS and when X11
forwarding an application across systems, there exists a 22px
window border that we cannot detect or do anything about.  As this
test is to verify that the width/height changed beyond 800x600,
this assertion change should make the tests pass on more configurations.

Depends on D8409

Differential Revision: https://phabricator.services.mozilla.com/D8410

--HG--
extra : moz-landing-system : lando

testing/web-platform/tests/webdriver/tests/set_window_rect/set.py

@@ -5,7 +5,8 @@ import pytest
 from webdriver.transport import Response
 
 from tests.support.asserts import assert_error, assert_success
-from tests.support.helpers import document_hidden, is_fullscreen
+from tests.support.helpers import (available_screen_size, document_hidden,
+                                   is_fullscreen, screen_size)
 
 
 def set_window_rect(session, rect):
@@ -172,38 +173,31 @@ def test_height_width(session):
     session.window.position = (50, 50)
 
     original = session.window.rect
-    max = session.execute_script("""
-        return {
-          width: window.screen.availWidth,
-          height: window.screen.availHeight,
-        }""")
+    screen_width, screen_height = screen_size(session)
 
     response = set_window_rect(session, {
-        "width": max["width"] - 100,
-        "height": max["height"] - 100
+        "width": screen_width - 100,
+        "height": screen_height - 100
     })
     assert_success(response, {
         "x": original["x"],
         "y": original["y"],
-        "width": max["width"] - 100,
-        "height": max["height"] - 100
+        "width": screen_width - 100,
+        "height": screen_height - 100,
     })
 
 
 def test_height_width_larger_than_max(session):
-    max = session.execute_script("""
-        return {
-          width: window.screen.availWidth,
-          height: window.screen.availHeight,
-        }""")
+    screen_width, screen_height = screen_size(session)
+    avail_width, avail_height = available_screen_size(session)
 
     response = set_window_rect(session, {
-        "width": max["width"] + 100,
-        "height": max["height"] + 100
+        "width": screen_width + 100,
+        "height": screen_height + 100
     })
     rect = assert_success(response)
-    assert rect["width"] >= max["width"]
-    assert rect["height"] >= max["height"]
+    assert rect["width"] >= avail_width
+    assert rect["height"] >= avail_height
 
 
 def test_height_width_as_current(session):

testing/web-platform/tests/webdriver/tests/support/helpers.py

@@ -181,3 +181,34 @@ def is_fullscreen(session):
     return session.execute_script("""
         return !!(window.fullScreen || document.webkitIsFullScreen)
         """)
+
+
+def document_dimensions(session):
+    return tuple(session.execute_script("""
+        let {devicePixelRatio} = window;
+        let {width, height} = document.documentElement.getBoundingClientRect();
+        return [width * devicePixelRatio, height * devicePixelRatio];
+        """))
+
+
+def screen_size(session):
+    """Returns the available width/height size of the screen."""
+    return tuple(session.execute_script("""
+        return [
+            screen.availWidth,
+            screen.availHeight,
+        ];
+        """))
+
+
+def available_screen_size(session):
+    """
+    Returns the effective available screen width/height size,
+    excluding any fixed window manager elements.
+    """
+    return tuple(session.execute_script("""
+        return [
+            screen.availWidth - screen.availLeft,
+            screen.availHeight - screen.availTop,
+        ];
+        """))