Simplify tests for TemplateList class

In response to: [^1][^2][^3].

Originally there were three tests:

- One was testing the "get_user_template_folders" method directly.

- The other two were testing "get_template_folders", which calls
the "_user_" method if a user is passed - this is what the tests
were primarily checking, by passing or not passing a User object.

The two tests of "get_template_folders" also implicitly checked
that it filtered folders based on a "parent_folder_id". I wanted
to emulate the tests but it makes more sense to simplify them, as
the methods are now only used by TemplateList internally.

To simplify, we just keep just two tests to check that the overall
set of folders is filtered based on the presence of a User. We do
lose the implicit check of filtering by "parent_folder_id", but:

- We are still checking this implicitly in the sense that the loop
to generate the overall set of folders terminates. If the method
didn't do any filtering, the loop would be infinite.

- We need to acknowledge that these tests were incomplete to begin
with. There is also lots of coverage in higher level tests [^4],
although it's harder to reason exactly what is covered.

[^1]: https://github.com/alphagov/notifications-admin/pull/4258#discussion_r890144076
[^2]: https://github.com/alphagov/notifications-admin/pull/4258#discussion_r890151220
[^3]: https://github.com/alphagov/notifications-admin/pull/4258#discussion_r890147506
[^4]: 1787f9f42f/tests/app/main/views/test_template_folders.py

app/models/template_list.py

@@ -264,7 +264,6 @@ class TemplateListFolder(TemplateListItem):
         super().__init__(folder, ancestors)
         self.folder = folder
         self.service_id = service_id
-        self.folders = folders
         self.number_of_templates = len(templates)
         self.number_of_folders = len(folders)
 

tests/app/models/test_template_list.py

@@ -96,34 +96,7 @@ def test_template_list_yields_folders_visible_to_user(
     )
 
 
-def test_template_list_folder_yields_user_folders_when_user_id_passed_in(
-    notify_admin,
-    mock_get_template_folders,
-    mock_get_service_templates,
-    service_one,
-    active_user_with_permissions,
-    mocker
-):
-    mock_get_template_folders.return_value = _get_all_folders(active_user_with_permissions)
-    service = Service(service_one)
-    user = User(active_user_with_permissions)
-
-    second_parent = next(
-        result for result in TemplateList(service=service, user=user)
-        if result.id == VIS_PARENT_FOLDER_ID
-    )
-
-    result_folder_names = tuple(
-        result['name'] for result in second_parent.folders
-    )
-
-    assert result_folder_names == (
-        "2's Visible child",
-        ["2's Invisible child", "2's Visible grandchild"],
-    )
-
-
-def test_template_list_folder_yields_all_folders_when_user_id_not_passed_in(
+def test_template_list_yields_all_folders_without_user(
     mock_get_template_folders,
     mock_get_service_templates,
     service_one,
@@ -133,16 +106,20 @@ def test_template_list_folder_yields_all_folders_when_user_id_not_passed_in(
     mock_get_template_folders.return_value = _get_all_folders(active_user_with_permissions)
     service = Service(service_one)
 
-    second_parent = next(
-        result for result in TemplateList(service=service)
-        if result.id == VIS_PARENT_FOLDER_ID
-    )
-
     result_folder_names = tuple(
-        result['name'] for result in second_parent.folders
+        result.name for result in
+        TemplateList(service=service)
+        if result.is_folder
     )
 
     assert result_folder_names == (
+        "Invisible folder",
+        "Parent 1 - invisible",
+        "1's Invisible child",
+        "1's Visible grandchild",
+        "1's Visible child",
+        "Parent 2 - visible",
         "2's Invisible child",
+        "2's Visible grandchild",
         "2's Visible child",
     )