When running `dotnet test` show output of the `dotnet vstest` output sink

Question

Edit: Below is the former question originally posted with the title

xunit show ITestOutputHelper output when run in the console

After investigation (see comments), the question is still very much relevant and in need of an answer but it seems that it should be addressed to the vstest framework and around output sinks rather than xunit.

The specific question now is: When something is written to the dotnet vstest output sink, how do I get it to display when running dotnet test from the command line. Specifically I want to be able to set up a watcher with dotnet watch to run tests continuously and I care more about output than results (I am using this less as a testing system and more as a development notebook). And I don't want to be limited to visual studio or vscode.

Original Question:

In my test class I have

    [Fact]
    public void Test() {

       output.WriteLine("WHATEVER");

    }
    readonly ITestOutputHelper output;

    public GroceryTests(ITestOutputHelper output) => this.output = output;

When I run this through the vscode in-editor integration I can see the output in the Output pane. When I run it via dotnet test I do not. How do I get this output to show up via console?

try `-v n` or `-v d` on the commandline to up the log level. If that doesnt provide a way to do it, you could hack it by decorating the helper and `tee`ing it out to the console with `Console.WriteLine`? The xunit mechanism simply forwards to the test output sink that the `dotnet vstest` furnishes, which is captured and stored separately (this addresses the question of what happens when the outputs of concurrently running tests get interspersed). This stuff lives in https://github.com/microsoft/vstest — Ruben Bartelink, Apr 08 '20 at 06:21
so I tried `-v` and it tends to give a *ton* of output about what the framework itself is doing and what its loading but doesn't seem to log anything else. Been trying to trace through the message sink stuff, but even if I figured out the type graph there, how do I modify that? — George Mauer, Apr 08 '20 at 14:43
I'd personally choose a path from: A) go delve deep into `dotnet vstest` B) just decorate ITestOutputHelper with one that tees out to Console.WriteLine (goto A if that doestn work :( ) — Ruben Bartelink, Apr 08 '20 at 14:48
@RubenBartelink but simply teeing to `Console.WriteLine` won't actually group output to the test. It seems like that would not be any different from using `Console.WriteLine` to begin with and have all the same problems when tests are run in parallel. — George Mauer, Apr 08 '20 at 15:28
Of course - in that case this is a `dotnet vstest` question - it'd be nice to have a canonical issue to link to in a self-answer ;) — Ruben Bartelink, Apr 08 '20 at 15:30
xUnit team says they don't have access to this. [Posted a question to vstest](https://github.com/microsoft/vstest/issues/2389) — George Mauer, Apr 08 '20 at 17:52

weichch · Answer 1 · 2020-04-13T05:58:16.383

38

Just to share what worked for me (I am no expert of vstest sink stuff, so probably can't answer deeper questions):

I have a simple test like this:

public class UnitTest1
{
    private readonly ITestOutputHelper _output;

    public UnitTest1(ITestOutputHelper output)
    {
        _output = output;
    }

    [Fact]
    public void Test1()
    {
        _output.WriteLine("My message.");
    }
}

So if I watch / run this test in console:

dotnet watch test --logger:"console;verbosity=detailed"

I see output like:

  V XUnitTestProject1.UnitTest1.Test1 [5ms]
  Standard Output Messages:
 My message.

I am using .NET Core SDK 3.1.201.

edited Apr 13 '20 at 05:58

answered Apr 13 '20 at 05:52

weichch

9,306
1
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25

strange...I seem to be like several other people in that thread for whom it does not work. what VSTest adapter version are you using? – George Mauer Apr 13 '20 at 20:49
I was using xunit 2.4.0 and Microsoft.NET.Test.Sdk 16.5.0. What dotnet SDK are you using? I saw people in that thread can't see outputs when they are on some SDK versions. – weichch Apr 13 '20 at 21:50
Also the test app was `netcoreapp3.1` – weichch Apr 13 '20 at 21:56
ah, relief at last! merci. Works for my with net5 / xunit 2.4 on macos commandline – Chris F Carroll Nov 12 '21 at 14:45

score 12 · Answer 2 · edited Jun 11 '21 at 02:39

@weichch's answer works for me even without any specific log sink usage. The command dotnet test -l "console;verbosity=detailed" is showing me all the Console.WriteLines of my tests just fine. And doesn't clutter much.

Note that you can add --filter="Name=<MethodName>" to the command to run tests with such name.

My tests all have attribute [NonParallelizable].
Using dotnet 5

The command is also mentioned in this answer at github.

When running `dotnet test` show output of the `dotnet vstest` output sink

2 Answers2

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