Bug 1751954 - [marionette] Improve tests for PageLoadStrategy "none" in test_navigation.py. r=webdriver-reviewers,jgraham

By using an URL that is delaying any response by a certain
amount of time it is easier to check for the PageLoadStrategy
"none" as when we only have a lazily loaded resource where
the element to wait for might immediately be available.

Differential Revision: https://phabricator.services.mozilla.com/D137112

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

@@ -47,10 +47,6 @@ class BaseNavigationTestCase(WindowManagerMixin, MarionetteTestCase):
             "navigation_pushstate.html"
         )
         self.test_page_remote = self.marionette.absolute_url("test.html")
-        self.test_page_slow_coop = self.marionette.absolute_url("slow-coop")
-        self.test_page_slow_resource = self.marionette.absolute_url(
-            "slow_resource.html"
-        )
 
         if self.marionette.session_capabilities["platformName"] == "mac":
             self.mod_key = Keys.META
@@ -848,6 +844,23 @@ class TestTLSNavigation(BaseNavigationTestCase):
 
 
 class TestPageLoadStrategy(BaseNavigationTestCase):
+    def setUp(self):
+        super(TestPageLoadStrategy, self).setUp()
+
+        # Test page that delays the response and as such the document to be
+        # loaded. It is used for testing the page load strategy "none".
+        self.test_page_slow = self.marionette.absolute_url("slow")
+
+        # Similar to "slow" but additionally triggers a cross group navigation
+        # which triggers a replacement of the top-level browsing context.
+        self.test_page_slow_coop = self.marionette.absolute_url("slow-coop")
+
+        # Test page that contains a slow loading <img> element which delays the
+        # "load" but not the "DOMContentLoaded" event.
+        self.test_page_slow_resource = self.marionette.absolute_url(
+            "slow_resource.html"
+        )
+
     def tearDown(self):
         self.marionette.delete_session()
         self.marionette.start_session()
@@ -860,30 +873,33 @@ class TestPageLoadStrategy(BaseNavigationTestCase):
 
         # Navigate will return immediately. As such wait for the target URL to
         # be the current location, and the element to exist.
-        self.marionette.navigate(self.test_page_slow_resource)
-        Wait(self.marionette, timeout=self.marionette.timeout.page_load).until(
-            lambda _: self.marionette.get_url() == self.test_page_slow_resource,
-            message="Target page has not been loaded",
-        )
-        Wait(self.marionette, ignored_exceptions=errors.NoSuchElementException).until(
-            lambda _: self.marionette.find_element(By.ID, "slow")
-        )
+        self.marionette.navigate(self.test_page_slow)
+        with self.assertRaises(errors.NoSuchElementException):
+            self.marionette.find_element(By.ID, "delay")
+
+        Wait(
+            self.marionette,
+            ignored_exceptions=errors.NoSuchElementException,
+            timeout=self.marionette.timeout.page_load,
+        ).until(lambda _: self.marionette.find_element(By.ID, "delay"))
+
+        self.assertEqual(self.marionette.get_url(), self.test_page_slow)
 
     def test_none_with_new_session_waits_for_page_loaded(self):
         self.marionette.delete_session()
         self.marionette.start_session({"pageLoadStrategy": "none"})
 
         # Navigate will return immediately.
-        self.marionette.navigate(self.test_page_slow_resource)
+        self.marionette.navigate(self.test_page_slow)
 
         # Make sure that when creating a new session right away it waits
         # until the page has been finished loading.
         self.marionette.delete_session()
         self.marionette.start_session()
 
-        self.assertEqual(self.test_page_slow_resource, self.marionette.get_url())
-        self.assertEqual("complete", self.ready_state)
-        self.marionette.find_element(By.ID, "slow")
+        self.assertEqual(self.marionette.get_url(), self.test_page_slow)
+        self.assertEqual(self.ready_state, "complete")
+        self.marionette.find_element(By.ID, "delay")
 
     def test_none_with_new_session_waits_for_page_loaded_remoteness_change(self):
         self.marionette.delete_session()
@@ -897,8 +913,8 @@ class TestPageLoadStrategy(BaseNavigationTestCase):
         self.marionette.delete_session()
         self.marionette.start_session()
 
-        self.assertEqual(self.test_page_slow_coop, self.marionette.get_url())
-        self.assertEqual("complete", self.ready_state)
+        self.assertEqual(self.marionette.get_url(), self.test_page_slow_coop)
+        self.assertEqual(self.ready_state, "complete")
         self.marionette.find_element(By.ID, "delay")
 
     def test_eager(self):
@@ -906,8 +922,8 @@ class TestPageLoadStrategy(BaseNavigationTestCase):
         self.marionette.start_session({"pageLoadStrategy": "eager"})
 
         self.marionette.navigate(self.test_page_slow_resource)
-        self.assertEqual("interactive", self.ready_state)
-        self.assertEqual(self.test_page_slow_resource, self.marionette.get_url())
+        self.assertEqual(self.ready_state, "interactive")
+        self.assertEqual(self.marionette.get_url(), self.test_page_slow_resource)
         self.marionette.find_element(By.ID, "slow")
 
     def test_normal(self):
@@ -915,8 +931,8 @@ class TestPageLoadStrategy(BaseNavigationTestCase):
         self.marionette.start_session({"pageLoadStrategy": "normal"})
 
         self.marionette.navigate(self.test_page_slow_resource)
-        self.assertEqual(self.test_page_slow_resource, self.marionette.get_url())
-        self.assertEqual("complete", self.ready_state)
+        self.assertEqual(self.marionette.get_url(), self.test_page_slow_resource)
+        self.assertEqual(self.ready_state, "complete")
         self.marionette.find_element(By.ID, "slow")
 
     def test_strategy_after_remoteness_change(self):
@@ -931,4 +947,4 @@ class TestPageLoadStrategy(BaseNavigationTestCase):
         self.marionette.navigate("about:robots")
         self.assertFalse(self.is_remote_tab, "Tab has remoteness flag set")
         self.marionette.navigate(self.test_page_slow_resource)
-        self.assertEqual("interactive", self.ready_state)
+        self.assertEqual(self.ready_state, "interactive")