use AssertExtensions.SequenceEqual in a few places

[geoffkizer]

Related to #51480

Use AssertExtensions.SequenceEqual in a few places in the System.Net.Sockets tests.
Also some minor style/spelling cleanup.

@antonfirsov

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Issue Details

---

Related to #51480

Use AssertExtensions.SequenceEqual in a few places in the tests.
Also some minor style/spelling cleanup.

@antonfirsov

Author:	geoffkizer
Assignees:	-
Labels:	area-System.Net.Sockets
Milestone:	-

[geoffkizer]

/azp run runtime-libraries-coreclr outerloop

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[wfurt]

The Assert.Equal already compares the sequence e.g. the bytes, right? Is the goal to make it more visible?

[geoffkizer]

Assert.Equal does an IEnumerable-based comparison. The performance of this is terrible for large buffers. So terrible that it was dominating the total time of test runs in the stream conformance tests.

AssertExtensions.SequenceEqual does a span-based comparison, which is much much faster. Like 20x or more.

AssertExtensions.SequenceEqual also has some logic around reporting differences that's kind of nice, but that's secondary to the performance issue.

We should always use AssertExtensions.SequenceEqual for comparing buffers. Assert.Equal is fine for non-buffers.

[geoffkizer]

@dotnet/dnceng Getting errors from Azure DevOps, is this a known issue?

[ilyas1974]

Yes. We ran into a problem with the AzDO DB. We are tracking this in https://github.com/dotnet/core-eng/issues/12969

[wfurt]

that make sense.

[stephentoub]

The performance of this is terrible for large buffers.

This should no longer be the case with .NET 6. Are you still seeing that?

[stephentoub]

Scratch that, the Assert.Equal implementation looks to be different than i remember it. I could have sworn it was using Enumerable.SequenceEqual, which has addressed this problem. But a quick code inspection suggests it may not be.

[geoffkizer]

/azp run runtime-libraries-coreclr outerloop

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).