For .NET Core projects Stryker.NET can be run without any configuration. On .NET Framework projects the solution path is required.

The full list of Stryker.NET configuration options are:

Solution path (required .NET Framework)
Project file (required on some projects)
Test runner
Timeout time
Reporters
Logging to console
Excluding mutations
Excluding files (deprecated)
Mutate
Ignore methods
Custom tresholds
Coverage analysis
Abort testrun on test failure
Diff based file exclusion
Git diff source

Solution path

On .NET Framework projects Stryker needs your .sln file path.

dotnet stryker --solution-path "..\\ExampleProject.sln"
dotnet stryker -s "..\\ExampleProject.sln"

Stryker.NET needs the path to execute:

nuget restore "*.sln"

and

MSBuild.exe "*.sln"

Project file

When Stryker finds two or more project references inside your test project, it needs to know which project should be mutated. Pass the name of this project using:

dotnet stryker --project-file SomeProjectName.csproj
dotnet stryker -p SomeProjectName.csproj

Test Project file

When Stryker finds two or more project files in the working directory, it needs to which is your test project. Pass the name of this project using:

dotnet stryker --test-project-file ExampleTestProject.csproj
dotnet stryker -tp ExampleTestProject.csproj

Specify testrunner

Stryker supports dotnet test, the commandline testrunner and VsTest, the visual studio testrunner. VsTest is the default because it offers tight integration with all test frameworks (MsTest, xUnit, NUnit etc). Dotnet test can be used if VsTest causes issues for some reason. Please also submit an issue with us if you experience difficulties with VsTest.

dotnet stryker --test-runner dotnettest
dotnet stryker -tr dotnettest

Default: "vstest"

Timeout time

Some mutations can create endless loops inside your code. To detect and stop these loops, Stryker cancels a unit test run after a set time. Using this parameter you can increase or decrease the time before a test will time out.

dotnet stryker --timeout-ms 1000
dotnet stryker -t 1000

Default: "5000"

Reporters

During a mutation testrun one or more reporters can be enabled. A reporter will produce some kind of output during or after the mutation testrun.

dotnet stryker --reporters "['html', 'progress']"
dotnet stryker -r "['html', 'progress']"

You can find a list of all available reporters and what output they produce in the reporter docs

Default: "['cleartext', 'progress']"

Logging to console

To gain more insight in what Stryker does during a mutation testrun you can lower your loglevel.

dotnet stryker --log-level "debug"
dotnet stryker -l "debug"

All available loglevels are:

error
warning
info
debug
trace

Default: "info"

Logging to a file

When creating an issue for Stryker.NET on github you can include a logfile. File logging always uses loglevel trace.

dotnet stryker --log-file
dotnet stryker -f

Default: off

Maximum concurrent test runners

By default Stryker.NET will use as much CPU power as you allow it to use during a mutation testrun. You can lower this setting to lower your CPU usage.

dotnet stryker --max-concurrent-test-runners 4
dotnet stryker -c 4

This setting can also be used to disable parallel testing. This can be useful if your test project cannot handle parallel testruns.

dotnet stryker -c 1

Default: your number of logical processors / 2*

* This usually equals your physical processor count

Custom thresholds

If you want to decide on your own mutation score thresholds, you can configure this with extra parameters.

dotnet stryker --threshold-high 90 --threshold-low 75 --threshold-break 50
dotnet stryker -th 90 -tl 75 -tb 50

mutation score > threshold-high:
- Awesome! Your reporters will color this green and happy.
threshold-high > mutation score > threshold-low:
- Warning! Your reporters will display yellow/orange colors, watch out!
threshold-low < mutation score > threshold-break:
- Danger! Your reporters will display red colors, you're in the danger zone now.
threshold-break > mutation score:
- Error! The application will exit with exit code 1.

Default: 80, 60, 0

Excluding mutations

If you deem some mutations unwanted for your project you can disable mutations.

dotnet stryker --excluded-mutations "['string', 'logical']"
dotnet stryker -em "['string', 'logical']"

The mutations of these kinds will be skipped and not be shown in your reports. This can also speed up your performance on large projects. But don't get too exited, skipping mutations doesn't improve your mutation score ;)

Excluding files

⚠ This parameter is deprecated. Use Mutate instead.

If you decide to exclude files for unit testing, you can configure this with the following command:

dotnet stryker --files-to-exclude "['./ExampleClass.cs', './ExampleDirectory', './ExampleDirectory/ExampleClass2.cs']"
dotnet stryker -fte "['./ExampleClass.cs', './ExampleDirectory', './ExampleDirectory/ExampleClass2.cs']"

We recommend to use relative paths. Relative paths are automatically resolved. Absolute paths break easily on different devices. However it is also possible to use absolute paths.

When you want to exclude a large set of files, it is advised to use the stryker configuration file because it is easier to handle multiple files.

Default: []

Mutate

To specify which files should be mutated you can use file pattern to in- or excluded files or even only parts of a files. By default all files are included.

dotnet stryker --mutate "['C:/Repos/MyProject/MyFile.cs']"
dotnet stryker -m "['C:/Repos/MyProject/MyFile.cs']"

The patterns support globbing syntax to allow wildcards.

dotnet stryker --mutate "['**/*Services.cs']"
dotnet stryker -m "['**/*Services.cs']"

You can add an ! in front of the pattern to exclude all files that match the pattern.

dotnet stryker --mutate "['!**/*Factory.cs']"
dotnet stryker -m "['!**/*Factory.cs']"

When only exclude patterns are provided, all files will be included that do not match any exclude pattern. If both, include and exclude patterns, are provided, only the files that match an include pattern but not also an exclude pattern will be included. The order of the patterns is irrelevant.

Example:

Patterns	File	Will be mutated
[]	MyFolder/MyFactory.cs	Yes
[]	MyFolder/MyService.cs	Yes
['*/.*']	MyFolder/MyFactory.cs	Yes
['*/.*']	MyFolder/MyService.cs	Yes
['!**/MyFactory.cs']	MyFolder/MyFactory.cs	No
['!**/MyFactory.cs']	MyFolder/MyService.cs	Yes
['!/MyFactory.cs', '/My*.cs']	MyFolder/MyFactory.cs	No
['!/MyFactory.cs', '/My*.cs']	MyFolder/MyService.cs	Yes

To allow more fine grained filtering you can also specify the span of text that should be in- or excluded. A span is defined by the indices of the first character and the last character.

dotnet stryker --mutate "['MyFolder/MyService.cs{10..100}']"
dotnet stryker -m "['MyFolder/MyService.cs{10..100}']"

Ignore methods

If you would like to ignore some mutations that are passed as method parameters, you can do so by specifying which methods to ignore:

dotnet stryker --ignore-methods "['ToString', 'ConfigureAwait', '*Exception.ctor']"
dotnet stryker -im "['ToString', 'ConfigureAwait', '*Exception.ctor']"

Ignore methods will only affect mutations in directly passed parameters.

// This mutation will be skipped;
ConfigureAwait(true); 

// This mutation won't
var t = true;
ConfigureAwait(t);

You can also ignore constructors by specifying the type and adding the .ctor suffix.

dotnet stryker -im "['NotImplementedException.ctor']"

Both, method names and constructor names, support wildcards.

dotnet stryker -im "['*Log']" // Ignores all methods ending with log dotnet stryker -im "['*Exception.ctor']" // Ignores all exception constructors

Default: []

Use a config file

There is also the option to use a config file. To use a config file all you have to do is add a file called stryker-config.json in the root of your test project and add a configuration section called stryker-config. Then you can add the options you want to configure to the file.

Example config file:

{
    "stryker-config":
    {
        "test-runner": "vstest",
        "reporters": [
            "progress",
            "html"
        ],
        "log-level": "info",
        "log-file":true,
        "timeout-ms": 10000,
        "project-file": "ExampleProject.csproj",
        "max-concurrent-test-runners": 4,
        "threshold-high": 80,
        "threshold-low": 70,
        "threshold-break": 60,
        "file-patterns": [
            "!ExampleClass.cs",
            "!ExampleDirectory",
            "!ExampleDirectory/ExampleClass2.cs",
            "!C:\\ExampleRepo\\ExampleDirectory\\ExampleClass.cs"
        ],
        "excluded-mutations": [
            "string",
            "Logical operators"
        ],
        "ignore-methods": [
            "*Log*",
            "ToString",
            "*HashCode*"
        ]
    }
}

Config file location

If you want to integrate these settings in your existing settings json, make sure the section is called stryker-config and run stryker with the command

dotnet stryker --config-file-path <relativePathToFile>
dotnet stryker -cp <relativePathToFile>

Default: "./stryker-config.json"

Coverage analysis

Use coverage info to speed up execution. Possible values are: off, perTest, all, perIsolatedTest.

off: coverage data is not captured.
perTest: capture the list of mutants covered by each test. For every mutant that has tests, only the tests that cover a the mutant are tested. Fastest option.
all: capture the list of mutants covered by each test. Test only these mutants. Non covered mutants are assumed as survivors. Fast option.
perTestInIsolation: like 'perTest', but running each test in an isolated run. This results in more accurate coverage information for some mutants (see below), at the expanse of a longer startup time.

dotnet stryker --coverage-analysis perTest
dotnet stryker -ca perTest

Default: "perTest"

Notes on coverage analysis

The 'dotnet test' runner only supports all mode. This is due to dotnet test limitation
Results are not impacted by coverage analysis. If you identify a suspicious survivor, run Stryker again without coverage analysis and report an issue if this mutant is killed by this run.
when using perTest mode, mutants that are executed as part as some static constructor/initializer are run against all tests, as Stryker can not reliably capture coverage for those. This is a consequence of static constructors/initialisers being called only once during tests. This heuristic is not needed when using perTestInIsolation due to test being run one by one.

Abort test on fail

Abort unit testrun as soon as any one unit test fails. This can reduce the overall running time.

dotnet stryker --abort-test-on-fail
dotnet stryker -atof

Default: "on"

Diff

Enables the diff feature. It makes sure to only mutate changed files. Gets the diff from git by default.

dotnet stryker --diff
dotnet stryker -diff

Default: false

Git source

Sets the source branch to compare with the current code on file system, used for calculating the difference when --diff is enabled.

dotnet stryker --git-source "development"
dotnet stryker -gs "development"

Default: master

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Configuration.md

Configuration.md

Solution path

Project file

Test Project file

Specify testrunner

Timeout time

Reporters

Logging to console

Logging to a file

Maximum concurrent test runners

Custom thresholds

Excluding mutations

Excluding files

Mutate

Example:

Ignore methods

Use a config file

Config file location

Coverage analysis

Notes on coverage analysis

Abort test on fail

Diff

Git source

Files

Configuration.md

Latest commit

History

Configuration.md

File metadata and controls

Solution path

Project file

Test Project file

Specify testrunner

Timeout time

Reporters

Logging to console

Logging to a file

Maximum concurrent test runners

Custom thresholds

Excluding mutations

Excluding files

Mutate

Example:

Ignore methods

Use a config file

Config file location

Coverage analysis

Notes on coverage analysis

Abort test on fail

Diff

Git source