Replace Task.WhenAny + Task.Delay timeout pattern with .WaitAsync(TimeSpan)

[Copilot]

Task.WhenAny(task, Task.Delay(timeout)) leaks an undisposed timer and requires a separate Assert.Equal to detect timeout. .WaitAsync(TimeSpan) is simpler and throws TimeoutException natively on timeout, failing the test without extra assertions.

Changes

• dotnet/test/SessionTests.cs — replace 2-line WhenAny/Assert.Equal with a single WaitAsync call
• dotnet/test/MultiClientTests.cs — eliminate the timeout variable and Assert.Equal; chain .WaitAsync directly onto Task.WhenAll

// Before
var timeout = Task.Delay(TimeSpan.FromSeconds(10));
var allEvents = Task.WhenAll(client1Requested.Task, client2Requested.Task, ...);
Assert.Equal(allEvents, await Task.WhenAny(allEvents, timeout));

// After
await Task.WhenAll(client1Requested.Task, client2Requested.Task, ...)
    .WaitAsync(TimeSpan.FromSeconds(10));

Original prompt

The Task.WhenAny(task, Task.Delay(timeout)) pattern is used in tests to implement timeouts, but it has downsides: it creates a fire-and-forget Task.Delay timer that isn't disposed, and the pattern is more verbose than necessary. Replace all occurrences with the simpler .WaitAsync(TimeSpan) API.

There are two occurrences to fix:

1. dotnet/test/SessionTests.cs (around line 275)

Current code:

var completed = await Task.WhenAny(idleReceived.Task, Task.Delay(TimeSpan.FromSeconds(60)));
Assert.Equal(idleReceived.Task, completed);

Replace with:

await idleReceived.Task.WaitAsync(TimeSpan.FromSeconds(60));

The Assert.Equal check is no longer needed because .WaitAsync will throw a TimeoutException if the task doesn't complete in time, which will fail the test.

2. dotnet/test/MultiClientTests.cs (around line 141)

Current code:

var timeout = Task.Delay(TimeSpan.FromSeconds(10));
var allEvents = Task.WhenAll(
    client1Requested.Task, client2Requested.Task,
    client1Completed.Task, client2Completed.Task);
Assert.Equal(allEvents, await Task.WhenAny(allEvents, timeout));

Replace with:

await Task.WhenAll(
    client1Requested.Task, client2Requested.Task,
    client1Completed.Task, client2Completed.Task).WaitAsync(TimeSpan.FromSeconds(10));

The timeout variable and the Assert.Equal are no longer needed.

Please also search the entire repository for any other occurrences of this same pattern (Task.WhenAny combined with Task.Delay for timeout purposes) and fix them similarly.

The following is the prior conversation context from the user's chat exploration (may be truncated):

User: Create a PR to fix this to use .WaitAsync(TimeSpan.FromSeconds(60)) instead. Also search for any other occurrences of the same pattern (using a Task.Delay with WhenAny) and fix them.

Assistant:

I'll start by searching for all occurrences of the Task.WhenAny + Task.Delay pattern in the repository, and then create a PR to fix them all.

Assistant: I found two occurrences of the Task.WhenAny + Task.Delay pattern:

1. dotnet/test/SessionTests.cs (line ~275):

   var completed = await Task.WhenAny(idleReceived.Task, Task.Delay(TimeSpan.FromSeconds(60)));
   Assert.Equal(idleReceived.Task, completed);

2. dotnet/test/MultiClientTests.cs (line ~141):

   var timeout = Task.Delay(TimeSpan.FromSeconds(10));
   var allEvents = Task.WhenAll(
       client1Requested.Task, client2Requested.Task,
       client1Completed.Task, client2Completed.Task);
   Assert.Equal(allEvents, await Task.WhenAny(allEvents, timeout));

Let me create the PR to fix both.

Assistant: I've kicked off the Copilot coding agent to create a PR in github/copilot-sdk that replaces all instances of the Task.WhenAny(..., Task.Delay(...)) timeout pattern with the cleaner .WaitAsync(TimeSpan) API.

From my search, I found at least two occurrences:

1. dotnet/test/SessionTests.cs (line 275) — await Task.WhenAny(idleReceived.Task, Task.Delay(TimeSpan.FromSeconds(60))) with an Assert.Equal check
2. dotnet/test/MultiClientTests.cs (around line 141) — Task.WhenAny(allEvents, timeout) where timeout = Task.Delay(TimeSpan.FromSeconds(10))

Both will be replaced with .WaitAsync(TimeSpan), which throws a TimeoutException on timeout (failing the test naturally), eliminating the need for the separate Task.Delay variable and Assert.Equal checks.

Note: The search results are limited to 10 results, so there may be additional occurrences. The coding agent will do a thorough search of the full repository. You can view more results in the GitHub code search UI.

You'll receive the PR link shortly from the coding agent once it's ready.

This pull request was created from Copilot chat.

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[Copilot]

Pull request overview

Updates .NET test timeouts to use Task.WaitAsync(TimeSpan) (net8) instead of manual Task.WhenAny + assertions, simplifying async wait logic in the SDK’s test suite.

Changes:

• Replace Task.WhenAny(..., Task.Delay(...)) + equality assertions with WaitAsync(TimeSpan) in session event tests.
• Apply the same WaitAsync(TimeSpan) pattern to multi-client broadcast event synchronization.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
dotnet/test/SessionTests.cs	Simplifies waiting for session.idle by using WaitAsync(60s) instead of WhenAny + assert.
dotnet/test/MultiClientTests.cs	Simplifies waiting for broadcast tool events across two clients using WhenAll(...).WaitAsync(10s).

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