There are quite a lot of unittesting frameworks out there for .NET. I found this little feature comparison: [http://xunit.github.io/docs/comparisons.html][1]

Now I am to choose the best one for us. But how? Does it matter? Which one is most future proof and has a decent momentum behind it? Should I care about the features? While xUnit seems to be most modern and specifically designed for .NET, NUnit again seems to be the one that is widely accepted. MSTest again is already integrated into Visual Studio ...

  [1]: https://xunit.net/docs/comparisons

NUnit vs. MbUnit vs. MSTest vs. xUnit.net

I have a simple dotnet core class library with a single XUnit test method:

    TestLib.csproj:
    &lt;Project Sdk=&quot;Microsoft.NET.Sdk&quot;&gt;
    
      &lt;PropertyGroup&gt;
        &lt;TargetFramework&gt;netstandard2.0&lt;/TargetFramework&gt;
      &lt;/PropertyGroup&gt;
    
      &lt;ItemGroup&gt;
        &lt;PackageReference Include=&quot;Microsoft.NET.Test.SDK&quot; Version=&quot;15.9.0&quot; /&gt;
        &lt;PackageReference Include=&quot;xunit&quot; Version=&quot;2.4.1&quot; /&gt;
        &lt;PackageReference Include=&quot;xunit.runner.console&quot; Version=&quot;2.4.1&quot;&gt;
          &lt;IncludeAssets&gt;runtime; build; native; contentfiles; analyzers&lt;/IncludeAssets&gt;
          &lt;PrivateAssets&gt;all&lt;/PrivateAssets&gt;
        &lt;/PackageReference&gt;
        &lt;PackageReference Include=&quot;xunit.runner.visualstudio&quot; Version=&quot;2.4.1&quot;&gt;
          &lt;IncludeAssets&gt;runtime; build; native; contentfiles; analyzers&lt;/IncludeAssets&gt;
          &lt;PrivateAssets&gt;all&lt;/PrivateAssets&gt;
        &lt;/PackageReference&gt;
        &lt;PackageReference Include=&quot;xunit.runners&quot; Version=&quot;2.0.0&quot; /&gt;
      &lt;/ItemGroup&gt;
    
    &lt;/Project&gt;

    BasicTest.cs:
    using Xunit;
    
    namespace TestLib
    {
        public class BasicTest
        {
            [Fact(DisplayName = &quot;Basic unit test&quot;)]
            [Trait(&quot;Category&quot;, &quot;unit&quot;)]
            public void TestStringHelper()
            {
                var sut = &quot;sut&quot;;
                var verify = &quot;sut&quot;;
    
                Assert.Equal(sut, verify);
            }
        }
    }

If I enter the project on the CLI and type `dotnet build` the project builds. If I type `dotnet test` I get this:

    C:\git\Testing\TestLib&gt; dotnet test
    C:\git\Testing\TestLib\TestLib.csproj : warning NU1701: Package &#39;xunit.runner.visualstudio 2.4.1&#39; was restored using &#39;.NETFramework,Version=v4.6.1&#39; instead of the project target framework &#39;.NETStandard,Version=v2.0&#39;. This package may not be fully compatible with your project.
    Build started, please wait...
    C:\git\Testing\TestLib\TestLib.csproj : warning NU1701: Package &#39;xunit.runner.visualstudio 2.4.1&#39; was restored using &#39;.NETFramework,Version=v4.6.1&#39; instead of the project target framework &#39;.NETStandard,Version=v2.0&#39;. This package may not be fully compatible with your project.
    Build completed.
    
    Test run for C:\git\Testing\TestLib\bin\Debug\netstandard2.0\TestLib.dll(.NETStandard,Version=v2.0)
    Microsoft (R) Test Execution Command Line Tool Version 16.0.0-preview-20181205-02
    Copyright (c) Microsoft Corporation.  All rights reserved.
    
    Starting test execution, please wait...
    Unable to find C:\git\Testing\TestLib\bin\Debug\netstandard2.0\testhost.dll. Please publish your test project and retry.
    
    Test Run Aborted.

What do I need to change to get the test to run?

If it helps, VS Code is not displaying the tests in its test explorer, either.

Unable to find testhost.dll. Please publish your test project and retry

I am attempting to unit test a WCF host management engine that I have written. The engine basically creates ServiceHost instances on the fly based on configuration. This allows us to dynamically reconfigure which services are available without having to bring all of them down and restart them whenever a new service is added or an old one is removed.

I have run into a difficulty in unit testing this host management engine, however, due to the way ServiceHost works. If a ServiceHost has already been created, opened, and not yet closed for a particular endpoint, another ServiceHost for the same endpoint can not be created, resulting in an exception. Because of the fact that modern unit testing platforms parallelize their test execution, I have no effective way to unit test this piece of code.

I have used xUnit.NET, hoping that because of its extensibility, I could find a way to force it to run the tests serially. However, I have not had any luck. I am hoping that someone here on SO has encountered a similar issue and knows how to get unit tests to run serially.

NOTE: [ServiceHost][1] is a WCF class, written by Microsoft. I don&#39;t have the ability to change it&#39;s behavior. Hosting each service endpoint only once is also the proper behavior...however, it is not particularly conducive to unit testing.


  [1]: http://msdn.microsoft.com/en-us/library/system.servicemodel.servicehost.aspx

Execute unit tests serially (rather than in parallel)

I have in my test suite a test that goes something like this:

    [Fact]
    public void VerifySomeStuff()
    {
        var stuffCollection = GetSomeStuff();

        Assert.Equal(1, stuffCollection.Count());
    }

This test works as I expect, but when I run it xUnit prints a warning:

&gt; warning xUnit2013: Do not use Assert.Equal() to check for collection size.

However, no alternative is suggested in the warning, and a google search takes me to the source code in xUnit for the test that verifies this warning is printed.

If `Assert.Equal()` isn&#39;t the correct way to verify the length of a collection, what is?

---

To clarify: I realize that I could &quot;trick&quot; xUnit into not emitting this warning by e.g. extracting a variable or using `Assert.True(stuff.Count() == 1)` instead. The latter is just hacky, and the former feels like if xUnit is e.g. trying to avoid multiple iterations of an `IEnumerable&lt;T&gt;`, then this is the wrong way to go (because I&#39;ll get compiler hints about that separately if it&#39;s an issue), and xUnit itself should never have to evaluate the input more than once (in fact it probably will get the same input regardless of variable extraction, because of how C# function calling works).

So, I&#39;m not just interested in removing that warning from my output. An answer to my question also explains *why* that warning is included in the library in the first place and *why* whatever approach I should use instead is better.

What&#39;s the idiomatic way to verify collection size in xUnit?

This question is about the unit testing framework [xUnit.net][1].

I need to run some code before any test is executed, and also some code after all tests are done. I thought there should be some kind of attribute or marker interface to indicate the global initialization and termination code, but couldn&#39;t find them.

Alternatively, if I invoke xUnit programmatically, I can also achieve what I want with the following code:

    static void Main()
    {
        try
        {
            MyGlobalSetup();
            RunAllTests();  // What goes into this method?
        }
        finally
        {
            MyGlobalTeardown();
        }
    }

Can anyone provide me a hint about how to declaratively or programmatically run some global setup/teardown code?

  [1]: https://xunit.net/

xUnit.net: Global setup + teardown?

[Xunit has a nice feature](https://stackoverflow.com/questions/9110419/test-parameterization-in-xunit-net-similar-to-nunit): you can create one test with a `Theory` attribute and put data in `InlineData` attributes, and xUnit will generate many tests, and test them all.


I want to have something like this, but the parameters to my method are not &#39;simple data&#39; (like `string`, `int`, `double`), but a list of my class:

    public static void WriteReportsToMemoryStream(
        IEnumerable&lt;MyCustomClass&gt; listReport,
        MemoryStream ms,
        StreamWriter writer) { ... }

Pass complex parameters to [Theory]

Are there any means in xUnit.net framework similar to the following features of NUnit?

    [Test, TestCaseSource(&quot;CurrencySamples&quot;)]
    public void Format_Currency(decimal value, string expected){}

    static object[][] CurrencySamples = new object[][]
    {
        new object[]{ 0m, &quot;0,00&quot;},
        new object[]{ 0.0004m, &quot;0,00&quot;},
        new object[]{ 5m, &quot;5,00&quot;},
        new object[]{ 5.1m, &quot;5,10&quot;},
        new object[]{ 5.12m, &quot;5,12&quot;},
        new object[]{ 5.1234m, &quot;5,12&quot;},
        new object[]{ 5.1250m, &quot;5,13&quot;}, // round
        new object[]{ 5.1299m, &quot;5,13&quot;}, // round
    }


This will generate 8 separate tests in NUnit GUI

    [TestCase((string)null, Result = &quot;1&quot;)]
    [TestCase(&quot;&quot;, Result = &quot;1&quot;)]
    [TestCase(&quot; &quot;, Result = &quot;1&quot;)]
    [TestCase(&quot;1&quot;, Result = &quot;2&quot;)]
    [TestCase(&quot; 1 &quot;, Result = &quot;2&quot;)]
    public string IncrementDocNumber(string lastNum) { return &quot;some&quot;; }

This will generate 5 separate tests and automatically compare the results (`Assert.Equal()`).

    [Test]
    public void StateTest(
        [Values(1, 10)]
        int input,
        [Values(State.Initial, State.Rejected, State.Stopped)]
        DocumentType docType
    ){}

This will generate 6 combinatorial tests. Priceless.

Few years ago I tried xUnit and loved it but it lacked these features. Can&#39;t live without them. Has something changed?

Test parameterization in xUnit.net similar to NUnit

I have an ASP.NET MVC Core application that I am writing unit tests for. One of the action methods uses User name for some functionality:

    SettingsViewModel svm = _context.MySettings(User.Identity.Name);

which obviously fails in the unit test. I looked around and all suggestions are from .NET 4.5 to mock HttpContext. I am sure there is a better way to do that. I tried to inject IPrincipal, but it threw an error; and I even tried this (out of desperation, I suppose):

    public IActionResult Index(IPrincipal principal = null) {
        IPrincipal user = principal ?? User;
        SettingsViewModel svm = _context.MySettings(user.Identity.Name);
        return View(svm);
    }

but this threw an error as well.
Couldn&#39;t find anything in the docs either...

Mocking IPrincipal in ASP.NET Core

I&#39;m new to xUnit.net and AutoFixture.

I&#39;m currently working on a &quot;testproject&quot; to get familiar with xUnit.net and Autofixture.
There is one little thing I don&#39;t understand.

What is the difference between `[Fact]` and `[Theory, AutoMoqData]`?

Could you please tell me if the following two pieces of code are equal?
I&#39;m asking this because the Test succeeds with both, but I want to learn it the right way.

    [Fact]
    public void UpdateVersionWillUpdateCorrectlyInRepository()
    {
        var fixture = new Fixture().Customize(new AutoMoqCustomization());
        var contract = fixture.Create&lt;VersionContract&gt;();
        var version = fixture.Create&lt;Version&gt;();

        fixture.Freeze&lt;Mock&lt;IContractMapper&gt;&gt;()
            .Setup(r =&gt; r.Map(contract)).Returns(version);

        var repMock = fixture.Freeze&lt;Mock&lt;VersionRepository&gt;&gt;();

        var sut = fixture.Create&lt;VersionManagementService&gt;();

        sut.UpdateVersion(contract);

        repMock.Verify(r =&gt; r.UpdateVersion(version));
    }

and

    [Theory, AutoMoqData]
    public void UpdateVersionWillUpdateCorrectlyInRepository(
        VersionContract contract,
        Version version,
        [Frozen]Mock&lt;IContractMapper&gt; mapMock,
        [Frozen]Mock&lt;VersionRepository&gt; repMock,
        VersionManagementService sut)
    {
        mapMock.Setup(r =&gt; r.Map(contract)).Returns(version);
    
        sut.UpdateVersion(contract);
    
        repMock.Verify(r =&gt; r.UpdateVersion(version));
    }

What makes me think that there is a difference are the Keywords `[Fact]` and `[Theory]`.

I&#39;m assuming that the `[Theory]` Keywords tells the xUnit.net framework that the supplied data comes from somewhere, where somewhere is Autofixture. Whereas `[Fact]` tells xUnit nothing about the origin of the data and I need to build the objects manually.

Difference between Fact and Theory? - xUnit.net

TL;DR - I&#39;m looking for xUnit&#39;s equivalent of MSTest&#39;s `AssemblyInitialize` (aka the ONE feature it has that I like).

Specifically I&#39;m looking for it because I have some Selenium smoke tests which I would like to be able to run with no other dependencies.  I have a Fixture that will launch IisExpress for me and kill it on disposal. But doing this before every test hugely bloats runtime.

I would like to trigger this code once at the start of testing, and dispose of it (shutting down the process) at the end.  How could I go about doing that? 

Even if I can get programmatic access to something like &quot;how many tests are currently being run&quot; I can figure something out.

Run code once before and after ALL tests in xUnit.net

I used to use these in NUnit and they are really useful. Any idea how to do something like that?

EDIT, CODE SAMPLE:

            bool condition = false;//would be nice not to have this
            observable.Subscribe(_ =&gt;
            {
                if (real test)
                    condition= true;//Assert.Pass()
            });
            StartObservable();
            Assert.True(condition);//Assert.Fail()      

Cannot find Assert.Fail and Assert.Pass or equivalent

I use Assert.Fail a lot when doing TDD. I&#39;m usually working on one test at a time but when I get ideas for things I want to implement later I quickly write an empty test where the name of the test method indicates what I want to implement as sort of a todo-list. To make sure I don&#39;t forget I put an Assert.Fail() in the body.

When trying out xUnit.Net I found they hadn&#39;t implemented Assert.Fail. Of course you can always Assert.IsTrue(false) but this doesn&#39;t communicate my intention as well. I got the impression Assert.Fail wasn&#39;t implemented on purpose. Is this considered bad practice? If so why?

----------

@Martin Meredith
That&#39;s not exactly what I do. I do write a test first and then implement code to make it work. Usually I think of several tests at once. Or I think about a test to write when I&#39;m working on something else. That&#39;s when I write an empty failing test to remember. By the time I get to writing the test I neatly work test-first.

@Jimmeh
That looks like a good idea. Ignored tests don&#39;t fail but they still show up in a separate list. Have to try that out.

@Matt Howells
Great Idea. NotImplementedException communicates intention better than assert.Fail() in this case

@Mitch Wheat
That&#39;s what I was looking for. It seems it was left out to prevent it being abused in another way I abuse it.


Is Assert.Fail() considered bad practice?

I have a large test suite in a .NET Core project. I can use the Test Explorer window to select a few tests to run.

I can also run the **whole** test suite on the command line with `dotnet test`. Is there a way to run only one (or a few) tests on the command line?

How do I run specific tests using dotnet test?

I don&#39;t think that this is specific to a language or framework, but I am using xUnit.net and C#.

I have a function that returns a random date in a certain range. I pass in a date, and the returning date is always in range of 1 to 40 years before the given date.

Now I just wonder if there is a good way to unit test this. The best approach seems to be to create a loop and let the function run i.e. 100 times and assert that every of these 100 results are in the desired range, which is my current approach.

I also realize that unless I am able to control my Random generator, there will not be a perfect solution (after all, the result IS random), but I wonder what approaches you take when you have to test functionality that returns a random result in a certain range?

Unit Testing with functions that return random results

So I have a test like the following:

    	[Fact]
		public void Test1()
		{
			Assert.ThrowsAsync&lt;ArgumentNullException&gt;(() =&gt; MethodThatThrows());
		}

		private async Task MethodThatThrows()
		{
			await Task.Delay(100);
			throw new NotImplementedException();
		}

To my surprise, Test1 passes successfully. To make it fail I have to write like this:

    Assert.Throws&lt;ArgumentNullException&gt;(() =&gt; MethodThatThrows().Wait());

What is the purpose of ThrowsAsync(), if it does not work in the scenario above?

xunit Assert.ThrowsAsync() does not work properly?

I have a xUnit.net Test as follows:

&lt;!-- language: lang-cs --&gt;

    static class MyTestClass
    {
        [Fact]
        static void MyTestMethod() 
        {
        }
    }

The xUnit plugin for VS 2012 says:

&gt; No tests found to run.

TestDriven.net runs it fine [but mentions something about Ad hoc](http://www.testdriven.net/quickstart.aspx#Ad%20Hoc%20Tests):

&gt; 1 passed, 0 failed, 0 skipped (see &#39;Task List&#39;), took 0.47 seconds (Ad hoc)


TeamCity, `xunit.gui.exe` and `xunit.console.exe` and Visual Studio also can&#39;t find `TestMethod`

(I&#39;ve got `xunit.runner.visualstudio` installed and VS is seeing some tests.)

What gives?

Why is the xUnit Runner not finding my tests

I just started testing xUnit.net, but it doesn&#39;t seem to capture any output (Console, Debug, Trace), as I would have expected.

Is that possible? I am using a sample .NET 4.0 class-library with xUnit.net 1.8.


xUnit.net does not capture console output

The latest version of VS Code already provides an easy way of running a single test as pointed on [Tyler Long&#39;s answer](https://stackoverflow.com/a/38372628/1140754) to the question [Debugging xunit tests in .NET Core and Visual Studio Code](https://stackoverflow.com/q/38146011/1140754).

However, I am looking how can I run **all tests** contained in a test suite class in VS Code (without debug)? 

The only way I found was adding to `launch.json` a specific configuration as the following one, but which I can only run in debug (I would like to run it without debug):

&lt;!-- language: lang-json --&gt;

    {
      &quot;name&quot;: &quot;.NET Core Xunit tests&quot;,
      &quot;type&quot;: &quot;coreclr&quot;,
      &quot;request&quot;: &quot;launch&quot;,
      &quot;preLaunchTask&quot;: &quot;build&quot;,
      &quot;program&quot;: &quot;/usr/local/share/dotnet/dotnet&quot;,
      &quot;args&quot;: [&quot;test&quot;],
      &quot;cwd&quot;: &quot;${workspaceRoot}/test/MyProject.Tests&quot;,
      &quot;externalConsole&quot;: false,
      &quot;stopAtEntry&quot;: false,
      &quot;internalConsoleOptions&quot;: &quot;openOnSessionStart&quot;
    }



How to run all tests in Visual Studio Code

If I set environment variables for a .Net Core web project in Visual Studio 2017 using the project properties page, I can read the value of the variable using `Environment.GetEnvironmentVariable`; however, when I set the environment variable for my xUnit testing project and then debug the test, `Environment.GetEnvironmentVariable` always returns null.  Is there something about the fact that it is a testing project that should prevent the variable from being used the same as with the web project?  If so, is there a way that I can set the environment variables for a test project?  Thank you.

Should GetEnvironmentVariable Work in xUnit Test?

I am using XUnit framework to test my C# code.

Is there any assert method available in this framework which does the object comparison? My intention is to check for equality of each of the object&#39;s public and private member variables. 

I tried those alternatives but seldom it works:

    1) bool IsEqual = (Obj1 == Obj2)
    2) Assert.Same(Obj1, Obj2) which I couldnt understand what happens internally



XUnit Assertion for checking equality of objects

The exact situation is I&#39;m doing E2E tests with Protractor.NET (.NET port of AngularJS&#39;s Protractor E2E framework) and I would like to make some web requests (and the API -- `System.Net.Http.HttpClient` -- has all Async/`Task` methods) to Arrange my test before I Act/Assert, only I need to do this same Arrange-ing for several tests.

I&#39;m using xUnit.net as my test runner they use an interface (`IUseFixture&lt;T&gt;`) for per-fixture setup code.  It would be nice if there was a `IAsyncUseFixture&lt;T&gt;` that had a `Task SetFixtureAsync(T t);` or something.  I don&#39;t think such a thing exists.  Additionally I don&#39;t think constructors can use `await` either, and constructors are the only other way to execute the same block of code per-test in xUnit.net.

What are my options?  `.Result`?  Isn&#39;t that bad practice (deadlock)?

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