Re-enable Akka.Streams.Tests.TCK NUnit tests

[Arkatufus]

Some of the Pub-Sub part of Akka.Streams do not have their own standalone spec/unit tests and rely on Reactive.Streams.TCK for testing instead.
I'm re-enabling NUnit because this is quite dangerous.

NOTE:
Reactive.Streams.TCK only supports NUnit up to 3.9-ish because it relies on specific code behavior inside NUnit. Above a certain version, NUnit is not binary compatible with Reactive.Streams.TCK anymore.
DO NOT UPDATE THE NUNIT PACKAGE VERSION, UNLESS THIS HAS BEEN RESOLVED BY THE TCK DEVS

[Arkatufus]

2020-08-20T21:09:31.9913360Z dotnet test -c Release --no-build --logger:trx --logger:"console;verbosity=normal" --framework net461 --results-directory "D:\a\1\s\TestResults" -- -parallel none
2020-08-20T21:09:32.8746579Z Test run for D:\a\1\s\src\core\Akka.Streams.Tests.TCK\bin\Release\net461\Akka.Streams.Tests.dll(.NETFramework,Version=v4.6.1)
2020-08-20T21:09:32.9939921Z Microsoft (R) Test Execution Command Line Tool Version 16.3.0
2020-08-20T21:09:32.9941609Z Copyright (c) Microsoft Corporation.  All rights reserved.
2020-08-20T21:09:32.9942247Z 
2020-08-20T21:09:33.1176512Z Starting test execution, please wait...
2020-08-20T21:09:33.1802951Z 
2020-08-20T21:09:33.1804293Z A total of 1 test files matched the specified pattern.
2020-08-20T21:09:34.6247562Z NUnit Adapter 3.17.0.0: Test execution started
2020-08-20T21:09:34.9014230Z Running all tests in D:\a\1\s\src\core\Akka.Streams.Tests.TCK\bin\Release\net461\Akka.Streams.Tests.dll
2020-08-20T21:09:36.6013857Z    NUnit3TestExecutor discovered 936 of 936 NUnit test cases
2020-08-20T21:09:39.0100105Z   √ Optional_spec104_mustSignalOnErrorWhenFails [530ms]
2020-08-20T21:09:39.0101621Z   √ Optional_spec105_emptyStreamMustTerminateBySignallingOnComplete [545ms]
2020-08-20T21:09:39.0293830Z Optional_spec111_maySupportMultiSubscribe: Skipped because tested publisher does NOT implement this OPTIONAL requirement.Reason for skipping was: Async error during test execution: ActorPublisher only supports one subscriber (which is allowed, see reactive-streams specification, rule 1.12)
< SNIP >
2020-08-20T21:13:38.6206228Z Untested_spec315_cancelMustNotThrowExceptionAndMustSignalOnError: Not verified using this TCK.
2020-08-20T21:13:38.6274175Z Untested_spec316_requestMustNotThrowExceptionAndMustOnErrorTheSubscriber: Not verified using this TCK.
2020-08-20T21:13:39.0064635Z NUnit Adapter 3.17.0.0: Test execution complete
2020-08-20T21:13:39.0582749Z [xUnit.net 00:00:00.00] xUnit.net VSTest Adapter v2.4.1 (32-bit Desktop .NET 4.0.30319.42000)
2020-08-20T21:13:40.0982413Z   ! Untested_spec301_mustNotBeCalledOutsideSubscriberContext
2020-08-20T21:13:40.0983546Z   ! Untested_spec304_requestShouldNotPerformHeavyComputations [1ms]
2020-08-20T21:13:40.0984521Z   ! Untested_spec305_cancelMustNotSynchronouslyPerformHeavyCompuatation [1ms]
2020-08-20T21:13:40.0985347Z   ! Untested_spec310_requestMaySynchronouslyCallOnNextOnSubscriber
2020-08-20T21:13:40.0986480Z   ! Untested_spec311_requestMaySynchronouslyCallOnCompleteOrOnError
2020-08-20T21:13:40.0987218Z   ! Untested_spec314_cancelMayCauseThePublisherToShutdownIfNoOtherSubscriptionExists
2020-08-20T21:13:40.0988165Z   ! Untested_spec315_cancelMustNotThrowExceptionAndMustSignalOnError
2020-08-20T21:13:40.0989059Z   ! Untested_spec316_requestMustNotThrowExceptionAndMustOnErrorTheSubscriber
2020-08-20T21:13:43.0238489Z [xUnit.net 00:00:03.96]   Discovering: Akka.Streams.Tests
2020-08-20T21:13:43.2518918Z [xUnit.net 00:00:04.19]   Discovered:  Akka.Streams.Tests
2020-08-20T21:13:43.6703395Z Results File: D:\a\1\s\TestResults\VssAdministrator_WIN-94OD2NJ61CK_2020-08-20_21_09_38.trx
2020-08-20T21:13:43.6705017Z 
2020-08-20T21:13:43.6706063Z Test Run Successful.
2020-08-20T21:13:43.6706653Z Total tests: 936
2020-08-20T21:13:43.6707333Z      Passed: 516
2020-08-20T21:13:43.6708599Z     Skipped: 420
2020-08-20T21:13:43.6710889Z  Total time: 4.1704 Minutes

[Aaronontheweb]

If we don't explicitly include an NUnit reference here, we'll take whatever NUnit version is used by Reactive.Streams.TCK as a transitive dependency. So maybe the safest way to handle this is to not explicitly specify an NUnit dependency at all? What do you think?

[Arkatufus]

Good idea, I'll do a quick check and update.

[Aaronontheweb]

https://dev.azure.com/dotnet/Akka.NET/_build/results?buildId=37591&view=logs&j=59d8d678-3f9b-55ef-c67e-99309e0aad31&t=ca366254-23e0-5149-5105-de91bebc95cc&l=11

2020-08-20T21:09:55.6666693Z ##[warning]No test result files matching **/*.trx were found.

Is there a way via dotnet test to get this output from the NUnit adapter, just like we do with XUnit today?

[Arkatufus]

No idea, I forgot about the trx part, let me check...

[Arkatufus]

The test assembly was set to Akka.Stream.Tests so it got picked up wrong and run under the Xunit test which causes a lot of weird things to happen. The test log should've flagged it, but I missed it. The build script skipped over it because it had TCK after the Tests keyword.

[Aaronontheweb]

@Arkatufus the tests ran fine on .NET Framework, but looks like they never ran at all on .NET Core for either Windows or Linux

[Arkatufus]

Yes, I removed .NET core from TargetFrameworks because Reactive.Streams.TCK only supports net45

[Arkatufus]

I need to add this back in, because .NET Core could not use the NUnit package referenced inside the TCK package

[Aaronontheweb]

nice work @Arkatufus