1 files changed, 55 insertions, 0 deletions
diff --git a/testing/marionette/harness/marionette_harness/tests/unit/test_element_id.py b/testing/marionette/harness/marionette_harness/tests/unit/test_element_id.py
new file mode 100644
index 0000000000..c7827daa08
--- /dev/null
+++ b/testing/marionette/harness/marionette_harness/tests/unit/test_element_id.py
@@ -0,0 +1,55 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import re
+from urllib.parse import quote
+
+from marionette_driver.by import By
+from marionette_driver.errors import NoSuchElementException, InvalidSelectorException
+from marionette_driver.marionette import WebElement
+
+from marionette_harness import MarionetteTestCase
+
+
+def inline(doc):
+    return "data:text/html;charset=utf-8,{}".format(quote(doc))
+
+
+id_html = inline("<p id=foo></p>")
+
+
+class TestElementID(MarionetteTestCase):
+    def setUp(self):
+        MarionetteTestCase.setUp(self)
+        self.marionette.timeout.implicit = 0
+
+    def test_id_is_valid_uuid(self):
+        self.marionette.navigate(id_html)
+        el = self.marionette.find_element(By.TAG_NAME, "p")
+        uuid_regex = re.compile(
+            "^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$"
+        )
+        self.assertIsNotNone(
+            re.search(uuid_regex, el.id),
+            "UUID for the WebElement is not valid. ID is {}".format(el.id),
+        )
+
+    def test_id_identical_for_the_same_element(self):
+        self.marionette.navigate(id_html)
+        found = self.marionette.find_element(By.ID, "foo")
+        self.assertIsInstance(found, WebElement)
+
+        found_again = self.marionette.find_element(By.ID, "foo")
+        self.assertEqual(found_again, found)
+
+    def test_id_unique_per_session(self):
+        self.marionette.navigate(id_html)
+        found = self.marionette.find_element(By.ID, "foo")
+        self.assertIsInstance(found, WebElement)
+
+        self.marionette.delete_session()
+        self.marionette.start_session()
+
+        found_again = self.marionette.find_element(By.ID, "foo")
+        self.assertNotEqual(found_again.id, found.id)