add status update functional test

[cotid-qualabs]

No description provided.

[gemini-code-assist]

Summary of Changes

Hello @cotid-qualabs, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a new functional test to validate the behavior of Alternative MPD events with status="update" in live streaming scenarios. The test ensures that an ongoing alternative content playback, initially without a maxDuration, can be updated mid-stream to include a maxDuration, causing the alternative content to terminate as expected.

Highlights

• New Functional Test: A new functional test has been added to verify the status="update" functionality for Alternative MPD events in live streams.
• Alternative MPD Status Update: The test specifically checks if a maxDuration can be successfully applied to an ongoing alternative MPD event via a status update, leading to early termination of the alternative content.

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[gemini-code-assist]

Code Review

This pull request adds a new functional test for the alternative MPD status update feature in live streams. The test logic is sound, but there are a few areas for improvement in the implementation to enhance maintainability and clarity. I've provided specific suggestions to address these points.

[gemini-code-assist]

For better maintainability and to avoid magic strings, please use the predefined constants from Constants.js.

• On this line and line 69, urn:mpeg:dash:event:alternativeMPD:replace:2025 should be Constants.ALTERNATIVE_MPD.URIS.REPLACE.
• On line 75, 'update' should be Constants.ALTERNATIVE_MPD.STATUS.UPDATE.
• On lines 154 and 167, 'replace' should be Constants.ALTERNATIVE_MPD.MODES.REPLACE.

Suggested change

	schemeIdUri: 'urn:mpeg:dash:event:alternativeMPD:replace:2025',
	schemeIdUri: Constants.ALTERNATIVE_MPD.URIS.REPLACE,

[gemini-code-assist]

The values for duration and earliestResolutionTimeOffset are hardcoded here and also in injectStatusUpdateEvent (lines 61 and 63). To improve maintainability and avoid duplication, please define them as constants at a higher scope (e.g., at the top of the file) and reuse them in both functions.

[gemini-code-assist]

This logic for adding the status update event is a bit confusing. The comment on line 57 (// Keep existing EventStreams...) is misleading because a fresh manifest is retrieved, so existingEventStream will always be undefined in this test's flow. The else block is always executed.

To improve clarity, you can simplify this block to directly add the new event stream, with a comment explaining why this works for an update.

Suggested change

	let existingEventStream = manifest.Period[0].EventStream.find(
	stream => stream.schemeIdUri === 'urn:mpeg:dash:event:alternativeMPD:replace:2025'
	);
	if (existingEventStream) {
	// Add the status update event to the existing EventStream
	existingEventStream.Event.push(statusUpdateEvent.Event[0]);
	} else {
	// Add as a new EventStream (this creates the update scenario)
	manifest.Period[0].EventStream.push(statusUpdateEvent);
	}
	// Add the status update event as a new EventStream. The player will process this
	// as an update because the event has status='update' and a matching ID to an active event.
	manifest.Period[0].EventStream.push(statusUpdateEvent);

[gemini-code-assist]

This assertion is redundant because the preceding assertion on line 188 (expect(actualAlternativeDuration).to.be.lessThan(10)) is stricter. You can safely remove this line.