Fallback to the deeplinking configuration for url by default

The behaviour we had in D2L applies to all LMS where we have tried deep
linking being Canvas the exceptions which overrides get_document.

The behaviour is:

- If we have the assignment in the DB use its document
- If not, but we have a record of the original assignment the current
  launch was copied from, use that.

- If not, check if we have deep linking configuration in the launch and
  use that. This is likely the first launch of the assignment.

- Return None otherwise.

lms/product/d2l/_plugin/misc.py

@@ -12,16 +12,6 @@ def get_ltia_aud_claim(self, lti_registration):
         # `lti_registration.token_url` as in other LMS
         return "https://api.brightspace.com/auth/token"
 
-    def get_document_url(self, request, assignment, historical_assignment):
-        url = super().get_document_url(request, assignment, historical_assignment)
-
-        if not url:
-            # In D2L support both deep linking and DB backed assignment.
-            # Use the DL url as a fallback.
-            url = self.get_deep_linked_assignment_configuration(request).get("url")
-
-        return url
-
     @classmethod
     def factory(cls, _context, request):
         return cls()

lms/product/plugin/misc.py

@@ -1,3 +1,5 @@
+from typing import Optional
+
 from lms.models import LTIParams, LTIRegistration
 from lms.services.html_service import strip_html_tags
 
@@ -52,11 +54,8 @@ def get_ltia_aud_claim(self, lti_registration: LTIRegistration) -> str:
         return lti_registration.token_url
 
     def get_document_url(
-        self,
-        request,  # pylint:disable=unused-argument
-        assignment,
-        historical_assignment,
-    ):
+        self, request, assignment, historical_assignment
+    ) -> Optional[str]:
         """Get a document URL from an assignment launch."""
 
         if assignment:
@@ -65,7 +64,8 @@ def get_document_url(
         if historical_assignment:
             return historical_assignment.document_url
 
-        return None
+        # For LMSes that support both DL and non-DL assignments fallback to the DL parameters
+        return self.get_deep_linked_assignment_configuration(request).get("url")
 
     def get_deeplinking_launch_url(self, request, _assignment_configuration: dict):
         """
@@ -79,7 +79,7 @@ def get_deeplinking_launch_url(self, request, _assignment_configuration: dict):
         # The assignment configuration we'll be retrieved by other methods (eg, custom parameters) so that parameter is not used here.
         return request.route_url("lti_launches")
 
-    def get_deep_linked_assignment_configuration(self, request):
+    def get_deep_linked_assignment_configuration(self, request) -> dict:
         """Get the configuration of an assignment that was original deep linked."""
         params = {}
         possible_parameters = ["url", "group_set"]

tests/unit/lms/product/d2l/_plugin/misc_test.py

@@ -1,4 +1,4 @@
-from unittest.mock import patch, sentinel
+from unittest.mock import sentinel
 
 import pytest
 
@@ -15,55 +15,10 @@ def test_get_ltia_aud_claim(self, plugin):
             == "https://api.brightspace.com/auth/token"
         )
 
-    def test_get_document_default_behaviour(self, plugin, MiscPlugin):
-        MiscPlugin.get_document_url.return_value = sentinel.url
-
-        assert (
-            plugin.get_document_url(
-                sentinel.request, sentinel.assignment, sentinel.historical_assignment
-            )
-            == sentinel.url
-        )
-
-    def test_get_document_deep_linked_fallback(
-        self, plugin, MiscPlugin, get_deep_linked_assignment_configuration
-    ):
-        MiscPlugin.get_document_url.return_value = None
-        get_deep_linked_assignment_configuration.return_value = {"url": sentinel.url}
-
-        assert (
-            plugin.get_document_url(
-                sentinel.request, sentinel.assignment, sentinel.historical_assignment
-            )
-            == sentinel.url
-        )
-
-    def test_get_document_returns_none(
-        self, plugin, MiscPlugin, get_deep_linked_assignment_configuration
-    ):
-        MiscPlugin.get_document_url.return_value = None
-        get_deep_linked_assignment_configuration.return_value = {}
-
-        assert not plugin.get_document_url(
-            sentinel.request, sentinel.assignment, sentinel.historical_assignment
-        )
-
     def test_factory(self, pyramid_request):
         plugin = D2LMiscPlugin.factory(sentinel.context, pyramid_request)
         assert isinstance(plugin, D2LMiscPlugin)
 
     @pytest.fixture
     def plugin(self):
         return D2LMiscPlugin()
-
-    @pytest.fixture
-    def MiscPlugin(self):
-        with patch("lms.product.d2l._plugin.misc.super") as patched:
-            yield patched.return_value
-
-    @pytest.fixture
-    def get_deep_linked_assignment_configuration(self, plugin):
-        with patch.object(
-            plugin, "get_deep_linked_assignment_configuration", autospec=True
-        ) as patched:
-            yield patched

tests/unit/lms/product/plugin/misc_test.py

@@ -1,4 +1,4 @@
-from unittest.mock import sentinel
+from unittest.mock import patch, sentinel
 
 import pytest
 
@@ -52,6 +52,13 @@ def test_get_document_url_with_assignment_in_db_copied_assignment(
 
         assert result == sentinel.document_url
 
+    def test_get_document_deep_linked_fallback(
+        self, plugin, get_deep_linked_assignment_configuration
+    ):
+        get_deep_linked_assignment_configuration.return_value = {"url": sentinel.url}
+
+        assert plugin.get_document_url(sentinel.request, None, None) == sentinel.url
+
     def test_get_document_url_with_no_document(self, plugin, pyramid_request):
         assert not plugin.get_document_url(pyramid_request, None, None)
 
@@ -112,6 +119,13 @@ def _with_custom(custom):
 
         return _with_custom
 
+    @pytest.fixture
+    def get_deep_linked_assignment_configuration(self, plugin):
+        with patch.object(
+            plugin, "get_deep_linked_assignment_configuration", autospec=True
+        ) as patched:
+            yield patched
+
     @pytest.fixture
     def pyramid_request(self, pyramid_request):
         pyramid_request.lti_params = LTIParams({"tool_consumer_instance_guid": "guid"})