xUnit doesn't write message to the output pane

Question

In Visual Studio 2015 Community I have a sample ASP.NET 5 (vNext) project and a project with unit tests (xUnit.net). The version of DNX is 1.0.0-beta5. My goal is to add messages during the test run to the output pane. Here I took a way to do this, so my unit test code looks like this:

using Xunit;
using Xunit.Abstractions;

namespace UnitTests
{

    public class UnitTest1
    {
        ITestOutputHelper output;

        public UnitTest1(ITestOutputHelper output)
        {
            this.output = output;
        }

        [Fact]
        public void TestTestTest()
        {
            output.WriteLine("Test Message");
            Assert.Equal(2, 2);
        }

    }
}

Visual Studio Test Explorer discovers this test (and that's OK), but all I have in the Output pane (from Tests) is:

------ Run test started ------
------ Test started: Project: UnitTests ------
Starting  Microsoft.Framework.TestHost [C:\Users\*******\.dnx\runtimes\dnx-clr-win-x86.1.0.0-beta5\bin\dnx.exe --appbase "C:\Users\*******\Documents\Visual Studio 2015\Projects\MvcMovie\UnitTests" Microsoft.Framework.ApplicationHost --port 55837 Microsoft.Framework.TestHost --port 55893]
Connected to Microsoft.Framework.TestHost
Running tests in 'C:\Users\*******\Documents\Visual Studio 2015\Projects\MvcMovie\UnitTests\project.json'
========== Run test finished: 1 run (0:00:03,2267169) ==========

Also, there is not any link "Output" under the selected test run information, like here: (Only "Test passed... Elapsed time ...")

What should I do to make this ITestOutputHelper work?

I have the same exact problem and haven't been able to find a solution. — Timothy Shields, Aug 05 '15 at 19:45
@TimothyShields however, it appears, when test fails. But not if it passes (like at the picture...) — Farfi, Aug 06 '15 at 06:59
@TimothyShields yes, in the same test if I write Assert.Equal(2, 3), i'll get a link "Output". Click on it results in new tab with a "Standart output" text block. — Farfi, Aug 07 '15 at 07:27
That it does not save the output for tests that succeed may actually be by design. — Timothy Shields, Aug 07 '15 at 15:04
@TimothyShields, the most likely, you're right, however, the picture in official manual shows the passed test with output — Farfi, Aug 10 '15 at 06:36
I was not able to replicate the problem in VS2015 Community WITHOUT the DNX test server. I think this points to the problem being with DNX. — Patrick Steadman, Nov 24 '15 at 22:03

score 8 · Answer 1 · edited Jun 25 '20 at 06:03

8

This solution works for me (Visual Studio 2017 and xUnit 2.2.0.3545).

Try adding the below configuration in the App.Config file. (I don't know why. It was just needed. If it doesn't exist, just add a new one in your test project.)

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <appSettings>
    <add key="xunit.diagnosticMessages" value="true"/>
  </appSettings>
</configuration>

The output information will be written in Test output as expected like below.

[xUnit.net 00:00:00.0853907]   Starting:    xxxAssemblyName (parallel test collections = on, max threads = 8)
[xUnit.net 00:00:00.1689373]     Example.xxxTestClassName [PASS]
[xUnit.net 00:00:00.1697265]       Output:
[xUnit.net 00:00:00.1700698]         xxxx your Test Message
[xUnit.net 00:00:00.1797303]   Finished:    xxxAssemblyName

edited Jun 25 '20 at 06:03

Peter Mortensen

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answered Jul 12 '17 at 09:04

Joe.wang

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**Note:** XML-based config has [deprecated](https://xunit.github.io/docs/configuring-with-xml), if possible use [JSON-based configuration](https://xunit.github.io/docs/configuring-with-json) now. – Matt Mar 27 '19 at 12:27
6

**xunit.runner.json:** `{ "$schema": "https://xunit.github.io/schema/current/xunit.runner.schema.json", "appDomain": "ifAvailable", "diagnosticMessages": true, "internalDiagnosticMessages": false, "longRunningTestSeconds": 4, "maxParallelThreads": 8, "methodDisplay": "classAndMethod", "methodDisplayOptions": "none", "parallelizeAssembly": true, "parallelizeTestCollections": true, "preEnumerateTheories": true, "shadowCopy": true }` – Matt Mar 29 '19 at 10:28
Your answer works, thank you!. **n.b.:** I am using the `xunit.runner.json` file above, setting `"diagnosticMessages": true` – Matt Mar 29 '19 at 10:31
1

Remember to set the file xunit.runner.json to CopyAlways, this got me spinning for a while – thor Sep 04 '19 at 12:03
2

@TGP1994 - Thanks for the information, yes both links are broken now. But I found new links here: [deprecated XML-based configuration](https://xunit.net/docs/configuring-with-xml) and [JSON-based configuration](https://xunit.net/docs/configuration-files). Hope that helps. – Matt Mar 03 '21 at 07:39
Transformed into json, I think it would look like: `{"$schema": "https://xunit.net/schema/current/xunit.runner.schema.json", "diagnosticMessages": true}`, name it `xunit.runner.json` and store it at the root directory of your project. – Matt Mar 19 '21 at 10:48
If you're using only this answer and it's still not working, note the absolutely vital bit of info in [Stato Machino's answer](https://stackoverflow.com/a/52450579/8417190). Took me a while to notice! You _must_ have a failing test, otherwise it won't output the diagnostic info to the main "Tests" output (but it will still output it to the individual tests in the Test Explorer window). – jsabrooke Dec 10 '21 at 12:04

score 7 · Answer 2 · edited Jun 25 '20 at 06:12

7

As explained on the xUnit GitHub page, I used

private readonly ITestOutputHelper output;

And this worked to me.

edited Jun 25 '20 at 06:12

Peter Mortensen

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answered Apr 18 '18 at 15:51

stefano

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Dont forget to add it to the test class constructor - its gonna be injected – Toumash Dec 02 '21 at 11:31
1

[Actual link](https://xunit.net/docs/capturing-output) – Murad Oct 20 '22 at 19:22

score 3 · Answer 3 · edited Jun 25 '20 at 06:11

I also ran into this the first time I used xUnit after using NUnit for a long time.

Surprisingly, xUnit does not support console output directly, but does offer some other ways to achieve the same thing.

https://xunit.github.io/docs/capturing-output.html

If you aren't really invested in xUnit I would say the simplest thing to do would just use NUnit or MSTest because both support simple console.writeline.

score 2 · Answer 4 · edited Jun 25 '20 at 06:23

For the ITestOutputHelper implementation only, the following works:

As reported by Joe.wang, you must put the {add key="xunit.diagnosticMessages" value="true"} in the App.config of the unit test project.

As reported by stefano, you must add a local member of type ITestOutputHelper to the test class. And you must add it to the parameters of a constructor and assign the injected object to the local member.

You should rebuild after instrumenting with an output method.

You must have a failing test.

Your call to the output method should precede the/a failing test.

This works per test! Not for a test suite.

score 1 · Answer 5 · answered Jan 09 '23 at 06:32

Got it to work with no configuration. Using .NET Core and VSCode, using Dependency Injection pattern, as described on XUnit.Net:

using Xunit;
using Xunit.Abstractions;

public class MyTestClass
{
    private readonly ITestOutputHelper output;

    public MyTestClass(ITestOutputHelper output)
    {
        this.output = output;
    }

    [Fact]
    public void MyTest()
    {
        var temp = "my class!";
        output.WriteLine("This is output from {0}", temp);
    }
}

And then run this command:

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

score 0 · Answer 6 · answered Jan 27 '23 at 09:08

Json configuration

As it seems that the above xml answer was not updated for a while, is obsolete and Matt answer in a comment is not the appropriate way to answer. Here is the minimal JSON configuration needed to display messages in output.

{   
  "$schema":"https://xunit.github.io/schema/current/xunit.runner.schema.json",   
  "diagnosticMessages": true
}

score -6 · Answer 7 · edited Jun 25 '20 at 06:00

-6

Just use Console.Write() and Console.WriteLine().

ReSharper hooks into this and you'll see the output in the test results.

edited Jun 25 '20 at 06:00

Peter Mortensen

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answered Apr 16 '17 at 20:51

Steffen Cole Blake

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12

xUnit doesn't write message to the output pane

7 Answers7

Json configuration