Run Unit Tests As You Modify Your Code

Introduction

Tired of save/build/run tests manually? I've written a Powershell script for watching *.cs file changes, rebuild and run unit tests as you go. Since it runs on a Powershell command-line, you can still work on your Visual Studio IDE while building and running the unit tests.

The approch here was to write a powershell script which will watch for *.cs file changes in the solution using a New-Object System.IO.FileSystemWatcher. It will refresh every second and when there is a modification, it will call msbuild for the test project followed by a vstest.console call which will run the tests itself.

Requirements

• Windows with Powershell
• At least RemoteSigned permission for executing scripts: Set-ExecutionPolicy RemoteSigned
• Visual Studio 2012+

Installation and Usage

You can clone this repository wherever you like:

git clone https://github.com/caiohamamura/CSharp-TestWatcher.git

Put C-TestWatcher path into environmental PATH or copy .bat and .ps1 to a folder included into environmental PATH.

The .bat file is configured to run in Visual Studio 2015. If this is not your version, edit watchTest.bat.

REM edit this
call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\Tools\VsDevCmd.bat"

In your test file, you have to specify a TestCategory:

[TestMethod, TestCategory("AnyCategory")]
public void TestMethod() ...

Then in a command prompt inside your test project path and run the command:

watchTest {AnyCategory} {TargetSetting [Debug]} {BuildPlatform [AnyCPU]} {TestPlatform [x64]}

How It Works

The Powershell script itself is really simple, the majority of the complexity is for parsing input parameters.

The script works this way:

1. Parse the input parameters or use default
2. Create an object $watcher = New-Object System.IO.FileSystemWatcher
3. Configure the $watcher to watch for changes in ..\*.cs files including subdirectories
4. Configure the action to run whenether there is a change. The action will:
   1. Build the test project calling msbuild with /p:Configuration=[AnyCPU] and /p:Platform=[x64] switches.
   2. Run the tests calling vstest.console using the DLL compiled in .\bin\[ProjectName].dll with /Platform:[x64] and /TestCaseFilter:TestCategory switches.
5. Bind the action to file modification events.

MSTest

The MSTest is a MS Visual Studio 2005+ command line tool for building projects, documentation here.

VSTest.console

The VSTest.console is a MS Visual Studio 2012+ command line tool for running test projects, documentation here. It relies on a built DLL test project to run the tests.

You can run all tests, specify which tests will run by calling its name using /Tests:Test1,Test2 switch or filter which tests will run using /TestCaseFilter switch. The TestCaseFilter switch can filter through:

• TestCategory: Set before method declaration through the attribute [TestCategory("MyCategory")]
• Priority: Set before method declaration through the attribute [Priority(0)]
• Name: Providing the full name including the namespace

The documentation also claims that it can use a *.runsettings xml file, but I couldn't find how to create such file properly in the documentation.