Adds test case for studio_metadata_mixin class

[farhan]

Ticket: #197 (comment)

The editable_metadata_fields property on VideoBlock had no dedicated tests, leaving its field-level
transformations (type overrides, transcript language injection, license toggling, English transcript
merging) unverified during the XBlock extraction from edx-platform.

This PR adds:

• A new test_studio_metadata_mixin.py test file covering VideoBlock.editable_metadata_fields
• Tests for default field modifications (sub removal, transcripts/edx_video_id/handout type overrides,
  language list injection)
• Tests for license field removal/retention based on the settings service's licensing_enabled flag
• Tests for English transcript lookup via the video_config service, including merge-with-existing and
  TranscriptNotFoundError handling
• Uses DummyRuntime (no XModuleMixin) to ensure the block is exercised in its extracted form

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds unit tests covering VideoBlock.editable_metadata_fields behavior in StudioMetadataMixin, validating field transformations, licensing behavior, and English transcript enrichment via services.

Changes:

• Introduces a new Django SimpleTestCase suite for editable_metadata_fields
• Adds helpers for constructing a VideoBlock and mocking runtime/services
• Covers default field modifications, licensing on/off, and transcript merge behavior

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[irfanuddinahmad]

Code Review

Overview

This PR adds the first dedicated unit test file for VideoBlock.editable_metadata_fields. The property was previously untested during the XBlock extraction from edx-platform. Coverage targets: field-level transformations (type overrides, sub removal, language injection), license toggling, and English transcript lookup via video_config.

The overall structure is clean and the intent is well-communicated. A few gaps and style points worth addressing before merge.

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What Works Well

• Clear section separators (# ---) and descriptive test names make the file easy to navigate.
• _service_stub as a @staticmethod is a clean, reusable pattern for wiring a single service mock.
• @override_settings(ALL_LANGUAGES=...) at the class level is the right place to put it.
• Good use of _base_fields to keep test setup DRY without hiding intent.

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Issues & Suggestions

Medium — Missing edge cases

1. public_access when public_url=None is never asserted.
   test_default_field_modifications calls _get_fields() (no public_url) but makes no assertion about public_access. Either assert the field is unchanged, or document that the production code doesn't touch public_access when the URL is absent. This is currently an invisible branch.

2. License field with no settings service.
   There is no test for: _get_fields(include_license=True) where service=None (the default — all services return None). What happens to license in this case? Retained? Removed? This branch is untested.

3. English transcript when sub is empty.
   Tests for video_config explicitly set self.block.sub = 'some_sub_id' to make possible_sub_ids non-empty. There is no test confirming that when sub is empty the transcript lookup is skipped and transcripts.value is unmodified. That's a meaningful branch in the production code.

Medium — Test does two things

4. test_field_modifications_with_custom_args tests two unrelated scenarios.
   It tests transcripts.value passthrough and public_access enrichment in one test. Split it into test_transcripts_value_passthrough and test_public_access_enriched_when_url_present. Single-assertion tests are much easier to diagnose on failure.

Minor — Style / coupling

5. instantiate_block as a module-level function.
   It is only used by this test class. Moving it in as a @staticmethod (or @classmethod) keeps the test class self-contained and makes the relationship to the class explicit.

6. Hardcoded '/handler/block/handler' couples the assertion to DummyRuntime's internals.
   Consider asserting on a more stable invariant (e.g., assert 'handler' in fields['transcripts']['urlRoot']), or add an inline comment explaining the dependency so a reader doesn't have to go spelunking through DummyRuntime to understand why this URL is expected.

7. 4-level nested with blocks in _get_fields are hard to scan.
   Python 3 allows parenthesized with on multiple lines:

   with (
       patch.object(self.block, '_get_editable_metadata_fields', return_value=self._base_fields(include_license)),
       patch.object(self.block, 'get_transcripts_info', return_value={'sub': '', 'transcripts': transcripts or {}}),
       patch.object(self.block, 'get_public_video_url', return_value=public_url),
       patch.object(self.block.runtime, 'service', **service_kwargs),
   ):
       return self.block.editable_metadata_fields

8. self.block.sub = 'some_sub_id' mutates shared state without comment.
   It's safe here because setUp re-creates self.block per test, but a brief comment (# triggers possible_sub_ids to be non-empty) would help future readers who might not realize why this assignment is required.

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Summary

Severity	Count
Medium (missing coverage)	3
Medium (test design)	1
Minor (style/coupling)	4

Good foundational PR — the happy paths and primary error path are all covered. The main asks before merge are: test public_access when URL is absent, test license behavior when there is no settings service, and test the sub-is-empty branch for transcript lookup. The style points are optional but would improve long-term maintainability.

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.