Continuous testing for .net core
Visual Studio 2017 is already there and it’s awesome.
One of the best features I’ve seen is the Live Unit Testing. The bad news is: it does not yet support .net core :(
It’s not the same, but one thing you can use to automatically run your tests every time you change some file is the command line dotnet watch.
Let’s create one example:
Create your lib project:
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C:\dev\temp>md lib C:\dev\temp>cd lib C:\dev\temp\lib>dotnet new classlib Content generation time: 100,8878 ms The template "Class library" created successfully. C:\dev\temp\lib>dotnet restore Restoring packages for C:\dev\temp\lib\lib.csproj... Generating MSBuild file C:\dev\temp\lib\obj\lib.csproj.nuget.g.props. Generating MSBuild file C:\dev\temp\lib\obj\lib.csproj.nuget.g.targets. Writing lock file to disk. Path: C:\dev\temp\lib\obj\project.assets.json Restore completed in 1,69 sec for C:\dev\temp\lib\lib.csproj. NuGet Config files used: C:\Users\andrecarlucci\AppData\Roaming\NuGet\NuGet.Config C:\Program Files (x86)\NuGet\Config\Microsoft.VisualStudio.Offline.config Feeds used: https://api.nuget.org/v3/index.json C:\Program Files (x86)\Microsoft SDKs\NuGetPackages\ C:\dev\temp\lib>cd.. |
Create your test project:
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C:\dev\temp>md test C:\dev\temp>cd test C:\dev\temp\test>dotnet new xunit Content generation time: 59,5689 ms The template "xUnit Test Project" created successfully. C:\dev\temp\test> |
Add reference to your lib project
Open your test.csproj and add this section anywhere:
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<ItemGroup> <ProjectReference Include="..\test\test.csproj" /> </ItemGroup> |
Add the DotNet Watcher tool to your test project
Still with your test.csproj open, add another item group:
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<ItemGroup> <DotNetCliToolReference Include="Microsoft.DotNet.Watcher.Tools" Version="1.0.0" /> </ItemGroup> |
Save and type:
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C:\dev\temp\test>dotnet restore |
Finally, start your continuous tests
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C:\dev\temp\test>dotnet watch test [90mwatch : [39mStarted Build started, please wait... Build completed. Test run for C:\dev\temp\test\bin\Debug\netcoreapp1.1\test.dll(.NETCoreApp,Version=v1.1) Microsoft (R) Test Execution Command Line Tool Version 15.0.0.0 Copyright (c) Microsoft Corporation. All rights reserved. Starting test execution, please wait... [xUnit.net 00:00:01.1104495] Discovering: test [xUnit.net 00:00:01.3775817] Discovered: test [xUnit.net 00:00:01.4713129] Starting: test [xUnit.net 00:00:01.7878213] Finished: test Total tests: 1. Passed: 1. Failed: 0. Skipped: 0. Test Run Successful. Test execution time: 3,8320 Seconds [90mwatch : [39mExited [90mwatch : [39m[93mWaiting for a file to change before restarting dotnet...[39m |
Note the message that it is waiting for file changes :)
Modify your test/lib projects and check the results
In your test/UnitTest1.cs:
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using lib; ... [Fact] public void Test1() { Assert.Equal(2, new Class1().DoubleIt(1)); } |
And your lib/Class1.cs
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public int DoubleIt(int value) { return 0; } |
Save both and watch your test fail :)
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[90mwatch : [39mStarted Build started, please wait... Build completed. Test run for C:\dev\temp\test\bin\Debug\netcoreapp1.1\test.dll(.NETCoreApp,Version=v1.1) Microsoft (R) Test Execution Command Line Tool Version 15.0.0.0 Copyright (c) Microsoft Corporation. All rights reserved. Starting test execution, please wait... [xUnit.net 00:00:01.0690239] Discovering: test [xUnit.net 00:00:01.3000697] Discovered: test [xUnit.net 00:00:01.3923048] Starting: test [xUnit.net 00:00:01.7705914] test.UnitTest1.Test1 [FAIL] [xUnit.net 00:00:01.7732986] Assert.Equal() Failure [xUnit.net 00:00:01.7735568] Expected: 2 [xUnit.net 00:00:01.7736792] Actual: 0 [xUnit.net 00:00:01.7756190] Stack Trace: [xUnit.net 00:00:01.7779834] C:\dev\temp\test\UnitTest1.cs(11,0): at test.UnitTest1.Test1() [xUnit.net 00:00:01.8179893] Finished: test Failed test.UnitTest1.Test1 Error Message: Assert.Equal() Failure Expected: 2 Actual: 0 Stack Trace: at test.UnitTest1.Test1() in C:\dev\temp\test\UnitTest1.cs:line 11 Total tests: 1. Passed: 0. Failed: 1. Skipped: 0. Test Run Failed. Test execution time: 3,7843 Seconds |
Fix your test
In lib/Class1.cs, change the result:
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public int DoubleIt(int value) { return value << 1; } |
And watch your cmd:
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[90mwatch : [39mStarted Build started, please wait... Build completed. Test run for C:\dev\temp\test\bin\Debug\netcoreapp1.1\test.dll(.NETCoreApp,Version=v1.1) Microsoft (R) Test Execution Command Line Tool Version 15.0.0.0 Copyright (c) Microsoft Corporation. All rights reserved. Starting test execution, please wait... [xUnit.net 00:00:01.1658403] Discovering: test [xUnit.net 00:00:01.4331220] Discovered: test [xUnit.net 00:00:01.5269952] Starting: test [xUnit.net 00:00:01.8384543] Finished: test Total tests: 1. Passed: 1. Failed: 0. Skipped: 0. Test Run Successful. Test execution time: 3,8702 Seconds [90mwatch : [39mExited [90mwatch : [39m[93mWaiting for a file to change before restarting dotnet...[39m |
\o/
Filtering your tests
You don’t need to run all tests all the time. You can filter them by DisplayName, FullyQualifiedName and Traits.
Also, these operators are allowed: =, != and ~ (contains).
Ex:
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dotnet watch test --filter "FullyQualifiedName=YourNamespace.TestClass1.Test1" |
More information about filtering tests here.
Happy testing :)
About
André Carlucci is the Director of Technology of Way2 Technology, Speaker, Microsoft MVP, Microsoft Regional Director, Intel Innovator, Intel Black Belt and DotNetFloripa and IoT usergroups organizer. He has 15 years of experience working on IT projects in Brazil and Europe. He is currently focused on software architecture and open-source projects. André is passionate about agile methodologies.
