test: add test for streaming with multiple events

[amithsourya]

Summary

Implements tests for streaming message scenarios where multiple events are received from the server, addressing Issue #52. This test validates the proper handling of event streams in AI agent-to-agent communication using the A2A Protocol.

Overview

The testOnMessageStreamNewMessageMultipleEventsSuccess() method verifies that the JSON-RPC handler correctly processes a sequence of multiple events during streaming communication:

1. Task Event (WORKING state) - Initial task state update
2. TaskArtifactUpdateEvent - Artifact generation during task execution
3. TaskStatusUpdateEvent (COMPLETED state) - Final task completion signal

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• Ensure the tests pass
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Fixes #52 🦕

---

[gemini-code-assist]

Summary of Changes

Hello @amithsourya, 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 critical new test case to enhance the robustness of the AI agent-to-agent communication protocol. The added test specifically validates the JSON-RPC handler's capability to accurately process a sequence of distinct events, such as task state updates, artifact generation, and final task completion signals, ensuring they are handled in the correct order during a streaming session. This improvement is vital for reliable asynchronous communication between agents.

Highlights

• New Streaming Test Case: A new test method, testOnMessageStreamNewMessageMultipleEventsSuccess, has been added to validate the JSON-RPC handler's ability to correctly process multiple events during a streaming communication session.
• Event Sequence Validation: The test specifically verifies the proper handling and order of a Task event (in WORKING state), a TaskArtifactUpdateEvent, and a TaskStatusUpdateEvent (in COMPLETED state) within a single stream.
• Issue Resolution: This pull request addresses and fixes Issue Add a test to JSONRPCHandlerTest for sending a streaming message where multiple events are received from the server #52, which likely pertained to the reliable handling of multi-event streaming scenarios.

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[gemini-code-assist]

Code Review

This pull request adds a valuable test case for handling multiple events in a streaming scenario. The test is well-structured and covers the intended functionality. My review includes a couple of suggestions to improve the test's robustness and maintainability. Specifically, I've pointed out a way to improve error handling within the Flow.Subscriber to prevent swallowing exceptions and make debugging easier. I've also suggested a more modern and concise way to write the assertions using JUnit 5 features.

[gemini-code-assist]

The onError implementation currently swallows the exception. This can cause the test to fail with a timeout, hiding the real cause of the failure. It's better to capture the error and fail the test explicitly with the actual exception.

You can achieve this by using an AtomicReference<Throwable> to store the error, releasing the CountDownLatch in onError, and then asserting that the AtomicReference is null after latch.await().

Example of what onError could look like:

@Override
public void onError(Throwable throwable) {
    error.set(throwable);
    // Release latch to prevent timeout
    while (latch.getCount() > 0) {
        latch.countDown();
    }
    subscription.cancel();
}

(This assumes error is an AtomicReference<Throwable> declared outside the subscriber). You would also need to add an assertion like Assertions.assertNull(error.get()); after the latch.await() call.

[amithsourya]

Fixed

[gemini-code-assist]

Since you are using a modern version of JUnit 5, you can make this code more concise. The assertInstanceOf method returns the casted object, which allows you to combine the assertion and the variable assignment into a single line, avoiding the explicit cast.

This simplification can be applied to the other event verifications in this test as well (for TaskArtifactUpdateEvent and TaskStatusUpdateEvent).

Suggested change

	assertInstanceOf(Task.class, results.get(0), "First event should be a Task");
	Task receivedTask = (Task) results.get(0);
	Task receivedTask = assertInstanceOf(Task.class, results.get(0), "First event should be a Task");

[amithsourya]

Fixed

[kabir]

Hi @amithsourya do you agree with the Gemini comments? :-)

[amithsourya]

Hi @kabir, I have addressed both the comments from Gemini 😄

[kabir]

THanks @amithsourya !