README.md

# Coverlet

[![Build Status](https://dev.azure.com/tonerdo/coverlet/_apis/build/status/coverlet-coverage.coverlet?branchName=master)](https://dev.azure.com/tonerdo/coverlet/_build/latest?definitionId=5&branchName=master) ![Code%20Coverage](https://img.shields.io/azure-devops/coverage/tonerdo/coverlet/5/master?label=Code%20Coverage) [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://github.com/coverlet-coverage/coverlet/blob/master/LICENSE)

| Driver | Current version | Downloads |
| --- | --- | --- |
| coverlet.MTP | [![NuGet](https://img.shields.io/nuget/v/coverlet.MTP.svg)](https://www.nuget.org/packages/coverlet.MTP/) | [![NuGet](https://img.shields.io/nuget/dt/coverlet.MTP.svg)](https://www.nuget.org/packages/coverlet.MTP/) |
| coverlet.collector | [![NuGet](https://img.shields.io/nuget/v/coverlet.collector.svg)](https://www.nuget.org/packages/coverlet.collector/) | [![NuGet](https://img.shields.io/nuget/dt/coverlet.collector.svg)](https://www.nuget.org/packages/coverlet.collector/)
| coverlet.msbuild | [![NuGet](https://img.shields.io/nuget/v/coverlet.msbuild.svg)](https://www.nuget.org/packages/coverlet.msbuild/) | [![NuGet](https://img.shields.io/nuget/dt/coverlet.msbuild.svg)](https://www.nuget.org/packages/coverlet.msbuild/) |
| coverlet.console | [![NuGet](https://img.shields.io/nuget/v/coverlet.console.svg)](https://www.nuget.org/packages/coverlet.console/) | [![NuGet](https://img.shields.io/nuget/dt/coverlet.console.svg)](https://www.nuget.org/packages/coverlet.console/) |

Coverlet is a cross platform code coverage framework for .NET, with support for line, branch and method coverage. It works with [.NET Framework](Documentation/KnownIssues.md#badimageformatexception-net-framework-47x-48x) on Windows and .NET Core on all supported platforms.

> [!NOTE]
> Coverlet only supports modern .NET [SDK-style](https://learn.microsoft.com/en-us/dotnet/core/project-sdk/overview) projects.

**Coverlet documentation reflect the current repository state of the features, not the released ones.**
**Check the [changelog](Documentation/Changelog.md) to understand if the documented feature you want to use has been officially released.**

## Main contents

* [QuickStart](#quick-start)
* [How It Works](#how-it-works)
* [Drivers features differences](Documentation/DriversFeatures.md)
* [Deterministic build support](#deterministic-build-support)
* [Known Issues](#known-issues)
* [Consume nightly build](#consume-nightly-build)
* [Feature samples](Documentation/Examples.md)
* [Cake Add-In](#cake-add-in)
* [Visual Studio Add-In](#visual-studio-add-in)
* [Changelog](Documentation/Changelog.md)
* [Roadmap](Documentation/Roadmap.md)

## Quick Start

Coverlet can be used through four different *drivers*

* VSTest engine integration
* MSBuild task integration
* As a .NET Global tool (supports standalone integration tests)
* **New** Microsoft Testing Platform integration (coverlet.MTP)

Coverlet supports only SDK-style projects <https://docs.microsoft.com/en-us/visualstudio/msbuild/how-to-use-project-sdk?view=vs-2019>

### **NEW** Microsoft Testing Platform Integration (coverlet.MTP)

### Installation (coverlet.MTP)

```bash
dotnet add package coverlet.MTP
```

> [!NOTE]
> Add the `coverlet.MTP` package only to test projects that use the [Microsoft Testing Platform](https://learn.microsoft.com/en-us/dotnet/core/testing/microsoft-testing-platform-intro). This package is designed for projects using `Microsoft.Testing.Platform` (MTP) as the test runner, not the traditional VSTest runner.

### Usage (coverlet.MTP)

Coverlet integrates with the Microsoft Testing Platform as an extension. To enable coverage collection, run your tests with the `--coverlet` flag:

```bash
dotnet run --project <your-test-project> -- --coverlet
```

Or when using `dotnet test` with MTP-enabled projects:

```bash
dotnet test --coverlet
```

After the above command is run, coverage report files will be generated in the test results directory. By default, reports are generated in `json` and `cobertura` formats.

#### Additional Options (coverlet.MTP)

| Option | Description |
| -------- | ------------- |
| `--coverlet` | Enable code coverage data collection |
| `--coverlet-output-format` | Output format(s) for coverage report (json, lcov, opencover, cobertura) |
| `--coverlet-include` | Include assemblies matching filters (e.g., [Assembly]Type) |
| `--coverlet-exclude` | Exclude assemblies matching filters (e.g., [Assembly]Type) |
| `--coverlet-include-test-assembly` | Include test assembly in coverage |

Example with options:

```bash
dotnet run --project <your-test-project> -- --coverlet --coverlet-output-format cobertura --coverlet-exclude "[xunit.]"
```

#### Requirements (coverlet.MTP)

* *.NET 8.0 SDK or newer*
* *Test project configured for Microsoft Testing Platform*
* *Reference to `Microsoft.Testing.Platform` packages*

### VSTest Integration (preferred due to [known issue](https://github.com/coverlet-coverage/coverlet/blob/master/Documentation/KnownIssues.md#1-vstest-stops-process-execution-earlydotnet-test))

### Installation (coverlet.collector)

```bash
dotnet add package coverlet.collector
```

> [!NOTE]
> You **MUST** add package only to test projects and if you create xunit test projects (`dotnet new xunit`) you will find the reference already present in `csproj` file because Coverlet is the default coverage tool for every .NET Core and >= *.NET 8* applications, you've only to update to last version if needed. Add `coverlet.collector` *OR* `coverlet.msbuild` package in a test project.

### Usage (coverlet.collector)

Coverlet is integrated into the Visual Studio Test Platform as a [data collector](https://github.com/Microsoft/vstest-docs/blob/master/docs/extensions/datacollector.md). To get coverage simply run the following command:

```bash
dotnet test --collect:"XPlat Code Coverage"
```

After the above command is run, a `coverage.cobertura.xml` file containing the results will be published to the `TestResults` directory as an attachment.

See [documentation](Documentation/VSTestIntegration.md) for advanced usage.

#### Requirements (coverlet.collector)

* *You need to be running .NET 8.0 SDK v8.0.112 or newer*
* *You need to reference version 17.12.0 and above of Microsoft.NET.Test.Sdk*

```xml
<PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
```

### MSBuild Integration (suffers of possible [known issue](https://github.com/coverlet-coverage/coverlet/blob/master/Documentation/KnownIssues.md#1-vstest-stops-process-execution-earlydotnet-test))

### Installation (coverlet.msbuild)

```bash
dotnet add package coverlet.msbuild
```

N.B. Typically you **MUST** add package only to test projects. Do not add `coverlet.msbuild` and `coverlet.collector` package in a test project.

### Usage (coverlet.msbuild)

Coverlet also integrates with the build system to run code coverage after tests. Enabling code coverage is as simple as setting the `CollectCoverage` property to `true`

```bash
dotnet test /p:CollectCoverage=true
```

After the above command is run, a `coverage.json` file containing the results will be generated in the root directory of the test project. A summary of the results will also be displayed in the terminal.

See [documentation](Documentation/MSBuildIntegration.md) for advanced usage.

#### Requirements (coverlet.msbuild)

Requires a runtime that support *.NET Standard 2.0 and above*

### .NET Global Tool ([guide](https://docs.microsoft.com/en-us/dotnet/core/tools/global-tools), suffers from possible [known issue](https://github.com/coverlet-coverage/coverlet/blob/master/Documentation/KnownIssues.md#1-vstest-stops-process-execution-earlydotnet-test))

### Installation (coverlet.console)

```bash
dotnet tool install --global coverlet.console
```

### Usage (coverlet.console)

The `coverlet` tool is invoked by specifying the path to the assembly that contains the unit tests. You also need to specify the test runner and the arguments to pass to the test runner using the `--target` and `--targetargs` options respectively. The invocation of the test runner with the supplied arguments **must not** involve a recompilation of the unit test assembly or no coverage result will be generated.

The following example shows how to use the familiar `dotnet test` toolchain:

```bash
coverlet /path/to/test-assembly.dll --target "dotnet" --targetargs "test /path/to/test-project --no-build"
```

*Note: The `--no-build` flag is specified so that the `/path/to/test-assembly.dll` assembly isn't rebuilt*

See [documentation](Documentation/GlobalTool.md) for advanced usage.

#### Requirements (coverlet.console)

.NET global tools rely on a .NET Core runtime installed on your machine <https://docs.microsoft.com/en-us/dotnet/core/tools/global-tools#what-could-go-wrong>

.NET Coverlet global tool requires *.NET 8.0 or above*

## How It Works

Coverlet generates code coverage information by going through the following process:

### Before Tests Run

* Locates the unit test assembly and selects all the referenced assemblies that have PDBs.
* Instruments the selected assemblies by inserting code to record sequence point hits to a temporary file.

### After Tests Run

* Restore the original non-instrumented assembly files.
* Read the recorded hits information from the temporary file.
* Generate the coverage result from the hits information and write it to a file.

## Deterministic build support

Coverlet supports coverage for deterministic builds. The solution at the moment is not optimal and need a workaround.
Take a look at [documentation](Documentation/DeterministicBuild.md).

## Are you in trouble with some feature? Check on [examples](Documentation/Examples.md)

## Known Issues

Unfortunately we have some [known issues](Documentation/KnownIssues.md)

## Cake Add-In

If you're using [Cake Build](https://cakebuild.net) for your build script you can use the [Cake.Coverlet](https://github.com/Romanx/Cake.Coverlet) add-in to provide you extensions to dotnet test for passing Coverlet arguments in a strongly typed manner.

## Visual Studio Add-In

If you want to visualize coverlet output inside Visual Studio while you code, you can use the following addins depending on your platform.

### Windows

If you're using Visual Studio on Windows, you can use the [Fine Code Coverage](https://marketplace.visualstudio.com/items?itemName=FortuneNgwenya.FineCodeCoverage) extension.
Visualization is updated when you run unit tests inside Visual Studio.

### Mac OS

If you're using Visual Studio for Mac, you can use the [VSMac-CodeCoverage](https://github.com/ademanuele/VSMac-CodeCoverage) extension.

## Consume nightly build

We offer nightly build of master for all packages.
See the [documentation](Documentation/ConsumeNightlyBuild.md)

## Issues & Contributions

If you find a bug or have a feature request, please report them at this repository's issues section. See the [CONTRIBUTING GUIDE](CONTRIBUTING.md) for details on building and contributing to this project.

## Coverlet Team

Author and owner

* [Toni Solarin-Sodara](https://github.com/tonerdo) (Inactive)

Co-maintainers

* [David Müller](https://github.com/daveMueller)
* [Bert](https://github.com/Bertk)
* [Peter Liljenberg](https://github.com/petli) (Inactive)
* [Marco Rossignoli](https://github.com/MarcoRossignoli) (Inactive)

## Code of Conduct

This project has adopted the code of conduct defined by the Contributor Covenant
to clarify expected behavior in our community.

For more information, see the [.NET Foundation Code of Conduct](https://dotnetfoundation.org/code-of-conduct).

## Credits

Part of the code is based on work done by OpenCover team <https://github.com/OpenCover>

## License

This project is licensed under the MIT license. See the [LICENSE](LICENSE) file for more info.

## Supported by the [.NET Foundation](https://dotnetfoundation.org/)