Generate Tests From MsBuild

You can invoke the “generate all” command from MsBuild. This allows you to update the unit test files before compiling the solution, which can be useful if feature files are regularly modified outside of Visual Studio.

Feature File Settings

When adding a feature file, Visual Studio automatically enters "SpecFlowSingleFileGenerator" as the Custom Tool in the file's properties. You need to remove the custom tool in all your feature files:

Editing Your Project

You need to add the following line to the end of the project file containing the feature files (e.g. with notepad):

<Import Project="..\packages\SpecFlow.2.2.0\tools\TechTalk.SpecFlow.targets" Condition="Exists('..\packages\SpecFlow.2.2.0\tools\TechTalk.SpecFlow.targets')" />

Example:

...
</ItemGroup>
<Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
<Import Project="..\packages\SpecFlow.2.2.0\tools\TechTalk.SpecFlow.targets" Condition="Exists('..\packages\SpecFlow.2.2.0\tools\TechTalk.SpecFlow.targets')" />
...
</Project>

The SpecFlow NuGet package contains all necessary files to support MsBuild generation in the tools folder. In order to be able to build your application in any environment, we recommend storing the SpecFlow tools together with your sources and using a relative path.

WARNING: If you are using NuGet package restore, restart Visual Studio and reopen your project. This is necessary so that Visual Studio can re-evaluate the project file and import the TechTalk.SpecFlow.targets.

Additional Options

The TechTalk.SpecFlow.targets file defines a number of default options in the following section:

<PropertyGroup>
    <ShowTrace Condition="'$(ShowTrace)'==''">false</ShowTrace>

    <OverwriteReadOnlyFiles Condition="'$(OverwriteReadOnlyFiles)'==''">false</OverwriteReadOnlyFiles>
    <ForceGeneration Condition="'$(ForceGeneration)'==''">false</ForceGeneration>
    <VerboseOutput Condition="'$(VerboseOutput)'==''">false</VerboseOutput>
</PropertyGroup>
  • ShowTrace: If set to true, trace information is output.
  • OverwriteReadOnlyFiles: Overwrites any read-only files in the target directory. This can be useful if your feature files are read-only and part of your repository.
  • ForceGeneration: Forces the code-behind files to be regenerated, even if the content has not changed.
  • VerboseOutput: Toggles verbose output for troubleshooting.

If you want to change these options, add the corresponding element to your project file before the <Import> element you added earlier.

Example:

<PropertyGroup>
  <ShowTrace>true</ShowTrace>
  <VerboseOutput>true</VerboseOutput>
</PropertyGroup>
...
</ItemGroup>
<Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
<Import Project="..\packages\SpecFlow.2.2.0\tools\TechTalk.SpecFlow.targets" Condition="Exists('..\packages\SpecFlow.2.2.0\tools\TechTalk.SpecFlow.targets')" />
...
</Project>

You can find an example here (project Bowling.SpecFlow)

Including Feature Files Dynamically

If you are also adding, renaming or deleting feature files outside of Visual Studio, you can include these files in your project dynamically. To do so, add the following lines to your project file in a text editor:

<ItemGroup>
  <!-- include all feature files from the folder "FeatureFiles" -->
  <None Include="FeatureFiles\**\*.feature" /> 
</ItemGroup>
<Target Name="AfterUpdateFeatureFilesInProject">
    <!-- include any files that specflow generated into the compilation of the project -->
    <ItemGroup>
        <Compile Include="@(SpecFlowGeneratedFiles)" />
    </ItemGroup>
</Target>

An example can be found here (project Bowling.SpecFlow.DynamicallyIncludedFeatureFiles)

Processing the Generated Files

You can also further process the generated files. The TechTalk.SpecFlow.targets file defines two targets (BeforeUpdateFeatureFilesInProject and AfterUpdateFeatureFilesInProject) that can be overridden. Furthermore it outputs the list of generated files for the MsBuild item @(SpecFlowGeneratedFiles).

The following example shows an overridden AfterUpdateFeatureFilesInProject target that moves the generated files to a separate folder:

<Target Name="AfterUpdateFeatureFilesInProject">
  <Move 
    SourceFiles="@(SpecFlowGeneratedFiles)" 
    DestinationFolder="MyGeneratedFiles" 
    OverwriteReadOnlyFiles="true" />
</Target>