Build a C#, F#, or Visual Basic Project

This guide covers build environment and configuration topics specific to C#, F#, and Visual Basic projects. Please make sure to read our Onboarding and General Build configuration guides first.

Community-Supported Language #

C#, F#, and Visual Basic support is community-supported in Travis CI. If you run into any problems, please report them in the Travis CI issue tracker and cc @joshua-anderson, @akoeplinger and @nterry.

Build Environment #

Currently, Travis builds your C#, F#, and Visual Basic project with the either the Mono or the .NET Core runtimes on Linux or macOS. Note that these runtimes do not implement the entire .NET framework, so Windows .NET framework programs may not be fully compatible and require porting.

Overview #

The setup for C#, F#, and Visual Basic projects looks like this:

language: csharp
solution: solution-name.sln

When the optional solution key is present, Travis will run NuGet package restore and build the given solution.

Test against Runtime and Version #

Mono #

By default, Travis CI will use the latest Mono release. It is also possible to test projects against specific versions of Mono. To do so, specify the version using the mono key in .travis.yml. For example, to test against the latest, 3.12.0 and 3.10.0:

language: csharp
mono:
  - latest
  - 3.12.0
  - 3.10.0
...

You can choose from the following Mono versions:

Note: even if you specify e.g. 3.12.0 the version used by your build may actually be 3.12.1 depending on what the latest version in the 3.12.x series is (it’s a limitation of the Xamarin repositories right now).

Alpha, Beta, and Weekly Channel: To install and test against upcoming Mono versions, specify alpha, beta, or weekly as the version number. Please report bugs you encounter on these channels to the Mono project so they can be fixed before release.

.NET Core #

By default, Travis CI does not test against .NET Core. To test against .NET Core, add the following to your .travis.yml. Note that at least one script <command> is required in order to build. Using dotnet restore is a good default.

language: csharp
mono: none
dotnet: 2.1.502
script:
 - dotnet restore
...

Note: You need to specify the version number of the .NET Core SDK (not the .NET Core Runtime).

The version numbers of the SDK can be found on the .NET Core website.

Test against Mono and .NET Core #

You can test against both Mono and .NET Core by using matrix.include. This example tests against both the latest mono and .NET Core:

language: csharp
solution: travis-mono-test.sln

jobs:
  include:
    - dotnet: 2.1.502
      mono: none
      env: DOTNETCORE=2  # optional, can be used to take different code paths in your script
    - mono: latest
...

Addons #

The Coverity Scan addon is not supported because it only works with msbuild on Windows right now.

Run Unit Tests for NUnit and xUnit #

To run your unit test suite, you’ll need to install a test runner first. The recommended approach is to install it from NuGet, as this also works on the container-based Travis infrastructure (i.e. it doesn’t need sudo).

The following examples show how you’d override install and script to install a test runner and pass your test assemblies to it for running the tests.

NUnit #

language: csharp
solution: solution-name.sln
install:
  - nuget restore solution-name.sln
  - nuget install NUnit.Console -Version 3.9.0 -OutputDirectory testrunner
script:
  - msbuild /p:Configuration=Release solution-name.sln
  - mono ./testrunner/NUnit.ConsoleRunner.3.9.0/tools/nunit3-console.exe ./MyProject.Tests/bin/Release/MyProject.Tests.dll

xUnit #

language: csharp
solution: solution-name.sln
install:
  - nuget restore solution-name.sln
  - nuget install xunit.runners -Version 1.9.2 -OutputDirectory testrunner
script:
  - msbuild /p:Configuration=Release solution-name.sln
  - mono ./testrunner/xunit.runners.1.9.2/tools/xunit.console.clr4.exe ./MyProject.Tests/bin/Release/MyProject.Tests.dll

Note: There’s a bug in Mono that makes xUnit 2.0 hang after test execution, we recommended you stick with 1.9.2 until it is fixed.

Use Solution-Level NuGet Packages #

Another way is to add the console testrunner of your choice as a solution-level NuGet package.

For many .NET projects this will be the file found at ./.nuget/packages.config.

nuget restore solution-name.sln will then install that package as well.

language: csharp
solution: solution-name.sln
script:
  - msbuild /p:Configuration=Release solution-name.sln
  - mono ./packages/xunit.runners.*/tools/xunit.console.clr4.exe ./MyProject.Tests/bin/Release/MyProject.Tests.dll

Notice the use of filename expansion (the *) in order to avoid having to hard code the version of the test runner.

MSTest #

The MSTest framework is supported when testing against .NET Core. Example:

language: csharp
mono: none
dotnet: 2.1.502
solution: solution-name.sln
script:
  - dotnet restore
  - dotnet test
...

Build Config Reference #

You can find more information on the build config format for C# in our Travis CI Build Config Reference.