Release Notes: October 6, 2017

Hello, v2 2.3!

Today, we're shipping xUnit.net 2.3; this includes RTM builds of the core framework and the Visual Studio runner. Ah, the sweet feeling of blue lights:

It's been nearly 8 months since the release of 2.2 RTM. That was strongly aligned with .NET Core 1.0, and in the intervening time, that team has now shipped a substantial 2.0 update. Similarly, xUnit.net 2.3 feels like it has a much improved experience for .NET Core users (both 1.x and 2.x).

One of the core reasons we've done xUnit.net has been to improve the day-to-day unit testing experience for .NET developers. At a previous job, we had discussions about adding Roslyn code analyzers to xUnit.net as a way to make our guidance more concrete. These rules and fixes would represent our knowledge with issues commonly faced by unit testers in general, and xUnit.net users in particular. Marcin Dobosz, one of our co-workers at the time, has stepped up and has done a tremendous job with the xUnit.net Analyzers project. Although this hasn't yet reached 1.0 status, we've already started including them when you reference the xunit meta-package; as a result, you will see our guidance light up as warnings and errors in your code.

Visual Studio 2017 has seen some substantial improvements since its release 7 months ago, with some great things on the horizon with 15.4 and 15.5. We are currently working on updated templates for the next release of the .NET SDK and a future update to Visual Studio 2017 which will include 2.3 references.

As always, we'd like to thank all the users who contributed to the success of xUnit.net through usage, feedback, and code contributions. We had too many contributors this time around to thank individually, so know that every bug reported, every line of code PR'd, every conversation contributed to on Slack, were all appreciated!

What's New

Core Framework

As mentioned above, the xunit meta-package now includes a reference to the xunit.analyzers package automatically. We feel most users will benefit from these helpful rules and fixes. If you decide you would like to opt out, please remove your reference to xunit, and instead add references to xunit.core and xunit.assert.
A significant amount of work was put into general performance improvements. The largest performance gains will be experienced by users who are running tests in the desktop CLR with app domains enabled (the default behavior). Additionally, we have spent time optimizing performance in the Visual Studio Test Explorer experience.
We added the ability to disable cross-collection parallelization for individual test collections, via the test collection definition (by setting [CollectionDefinition(DisableParallelization = true)]). Parallel-capable test collections will be run first (in parallel), followed by parallel-disabled test collections (run sequentially).
There have been several improvements to the assertion library, as well as new command line options (and MSBuild properties) to the test runners. Make sure to check out Intellisense and the command line runner help to see what's new!

.NET Core

A new runner for .NET Core has been added: dotnet xunit. This gives a first class experience for running xUnit.net tests that mirrors the functionality available to desktop CLR users via xunit.console.exe. We have updated Getting Started with .NET Core to show how to incorporate support for dotnet xunit.
The .NET Core console runner is also available directly via the xunit.runner.console NuGet package, and can be run via dotnet C:\Path\to\xunit.console.dll C:\Path\to\TestLibrary.dll. There are additional properties via MSBuild that can be used to automatically locate the runner; see the xUnit.net Integration Project for examples of how to use this directly from your .csproj files.
This is the first version to fully support .NET Core 2.0, and the support for .NET Core 1.0 has been greatly improved. In particular, users who noticed that we were copying large numbers of dependent DLLs will be happy to note that we have found a way around that. Also, any users who were previously trying to use libraries with native components (for example, System.Data.SqlClient) from .NET Core should now be able to properly use these packages (this fix affects all versions of .NET Core).

Breaking Changes

The xunit.runner.console NuGet package has been changed; notably, the path to the net452 executables has moved from tools\ to tools\net452\. You will need to update any paths which previously hard-coded this path.

The xunit.runner.msbuild NuGet package has been changed; notably, the names of the MSBuild runner DLLs now include the target platform. This means if you had a hard-coded path to xunit.runner.msbuild.dll, this will need to be replaced with xunit.runner.msbuild.net452.dll.

Important Notes

If you are using Visual Studio 2013, you must use NuGet 2.12 or later to use xUnit.net 2.3, because support for netstandard is required. You will not be able to use xUnit.net 2.3 with Visual Studio 2012 (if Visual Studio 2012 support is important, please stick with xUnit.net 2.1, the last version that officially supported 2012).

As a reminder: If you're extending xUnit.net and want to publish your extension as a NuGet package, you should import xunit.extensibility.core and/or xunit.extensibility.execution, not xunit or xunit.core. If you do this wrong, you might have problems generating your NuGet package via dotnet pack.

Release Notes

These release notes just include the highlights of what's new. You can review the individual release notes which contributed to 2.3:

RC 3 RC 2 RC 1 Beta 5 Beta 4 Beta 3 Beta 2 Beta 1