webdriver: fix is_fullscreen assertions

The "is True" and "is False" style is unnecessary as the return
values are boolean, which means "assert is_fullscreen(session)"
and "assert not is_fullscreen(session)" is sufficient.

Depends on D8404

Differential Revision: https://phabricator.services.mozilla.com/D8405

bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1492499
gecko-commit: 246b45eae45c12e0755be1665208309d2e9f4b6f
gecko-integration-branch: autoland
gecko-reviewers: automatedtester

webdriver/tests/fullscreen_window/fullscreen.py

@@ -26,7 +26,7 @@ def test_fullscreen(session):
     response = fullscreen(session)
     assert_success(response)
 
-    assert is_fullscreen(session) is True
+    assert is_fullscreen(session)
 
 
 def test_payload(session):
@@ -47,12 +47,12 @@ def test_payload(session):
 
 
 def test_fullscreen_twice_is_idempotent(session):
-    assert is_fullscreen(session) is False
+    assert not is_fullscreen(session)
 
     first_response = fullscreen(session)
     assert_success(first_response)
-    assert is_fullscreen(session) is True
+    assert is_fullscreen(session)
 
     second_response = fullscreen(session)
     assert_success(second_response)
-    assert is_fullscreen(session) is True
+    assert is_fullscreen(session)

webdriver/tests/fullscreen_window/user_prompts.py

@@ -24,41 +24,39 @@ def is_fullscreen(session):
 @pytest.fixture
 def check_user_prompt_closed_without_exception(session, create_dialog):
     def check_user_prompt_closed_without_exception(dialog_type, retval):
-        assert is_fullscreen(session) is False
+        assert not is_fullscreen(session)
 
         create_dialog(dialog_type, text=dialog_type)
 
         response = fullscreen(session)
         assert_success(response)
 
         assert_dialog_handled(session, expected_text=dialog_type, expected_retval=retval)
-
-        assert is_fullscreen(session) is True
+        assert is_fullscreen(session)
 
     return check_user_prompt_closed_without_exception
 
 
 @pytest.fixture
 def check_user_prompt_closed_with_exception(session, create_dialog):
     def check_user_prompt_closed_with_exception(dialog_type, retval):
-        assert is_fullscreen(session) is False
+        assert not is_fullscreen(session)
 
         create_dialog(dialog_type, text=dialog_type)
 
         response = fullscreen(session)
         assert_error(response, "unexpected alert open")
 
         assert_dialog_handled(session, expected_text=dialog_type, expected_retval=retval)
-
-        assert is_fullscreen(session) is False
+        assert not is_fullscreen(session)
 
     return check_user_prompt_closed_with_exception
 
 
 @pytest.fixture
 def check_user_prompt_not_closed_but_exception(session, create_dialog):
     def check_user_prompt_not_closed_but_exception(dialog_type):
-        assert is_fullscreen(session) is False
+        assert not is_fullscreen(session)
 
         create_dialog(dialog_type, text=dialog_type)
 
@@ -68,7 +66,7 @@ def check_user_prompt_not_closed_but_exception(dialog_type):
         assert session.alert.text == dialog_type
         session.alert.dismiss()
 
-        assert is_fullscreen(session) is False
+        assert not is_fullscreen(session)
 
     return check_user_prompt_not_closed_but_exception
 

webdriver/tests/maximize_window/maximize.py

@@ -24,11 +24,11 @@ def test_no_browsing_context(session, closed_window):
 
 def test_fully_exit_fullscreen(session):
     session.window.fullscreen()
-    assert is_fullscreen(session) is True
+    assert is_fullscreen(session)
 
     response = maximize(session)
     assert_success(response)
-    assert is_fullscreen(session) is False
+    assert not is_fullscreen(session)
 
 
 def test_restore_the_window(session):

webdriver/tests/set_window_rect/set.py

@@ -142,14 +142,14 @@ def test_no_change(session, rect):
 
 def test_fully_exit_fullscreen(session):
     session.window.fullscreen()
-    assert is_fullscreen(session) is True
+    assert is_fullscreen(session)
 
     response = set_window_rect(session, {"width": 400, "height": 400})
     value = assert_success(response)
     assert value["width"] == 400
     assert value["height"] == 400
 
-    assert is_fullscreen(session) is False
+    assert not is_fullscreen(session)
 
 
 def test_restore_from_minimized(session):