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The latest [release](https://github.com/Microsoft/VisualStudio-TestHost/releases) will install the required components into all supported versions of Visual Studio. After installing a new version of Visual Studio, you will need to reinstall the test host.
Test settings files are used to specify the version of Visual Studio to launch. [Example file](https://github.com/Microsoft/PTVS/blob/master/Build/default.14.0Exp.testsettings)
Add the `[HostType("VSTestHost")]` attribute to your unit tests, and your test will now launch VS and run within its process. The VS instance will be reused between tests, so make sure you clean everything up regardless of whether your test passes or fails. In [PTVS](https://github.com/Microsoft/PTVS) we use a [helper class](https://github.com/Microsoft/PTVS/blob/master/Common/Tests/Utilities.UI/UI/VisualStudioApp.cs) with `IDisposable` to ensure that failed tests do not affect later ones.
Use the `VSTestContext` static class to access the global service provider and DTE objects of the running Visual Studio instance. You can obtain a UI automation object with `AutomationElement.FromHandle(VSTestContext.DTE.MainWindow.HWnd)`.
For information about how this extension works, see the [Developer Guide](DeveloperGuide.md).
## Supported Versions
The following versions of Visual Studio may be used as test *targets*:
(The difference in support is due to changes in the unit test framework. If possible, tests should be launched with the same version as the test target.)
If `VSApplication` is set to `Mock`, no instance of Visual Studio will be launched and tests will be run in the current process. In this case, the `VSTestContext.IsMock` property will be `true` and `VSTestContext.ServiceProvider` should be set by your test run initializer.
