Skip to content
This repository has been archived by the owner on Nov 15, 2021. It is now read-only.


Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?


Failed to load latest commit information.

Putting OpenCover into archive mode

A long time ago OpenCover met a need and then slowly expanded on the request of others (and some crazy ideas of my own), in the last few years the development of OpenCover has been sporadic as I have pursued other interests. Now with the numerous releases of .NET core and the availability of other tools such at AltCover* that fill that same product space I feel the time has come to park OpenCover.

(*) I use AltCover myself as I am often using linux based containers as my target environment

Q. What about security patches/releases? A. I have activated dependabot and if necessary I may occasionally dust off the Windows box and boot up Visual Studio Community 2019 and apply the suggested fix; it is possible to manage commits and releases just through GitHub and AppVeyor.


OpenCover is a code coverage tool for .NET 2 and above (Windows OSs only - no MONO)*, with support for 32 and 64 processes and covers both branch and sequence points. OpenCover was started after attempts to make PartCover support 64-bit processes got just a little too complicated.

  • OpenCover should have few issues with any application compiled against any of the .NET Full Frameworks. Applications targetting .Net Core may encounter issues but using the -oldstyle switch usually works.

The latest releases can be downloaded from releases. Alternatively why not try the nuget package (this is the most popular).

Active Integrations
Build Build status
Coverage Coveralls Coveralls
Quality CodeFactor
Quality Coverity
Nuget Nuget Nuget
Agreements CLA assistant


The primary repo for the project is on GitHub and is also where the wiki and issues are managed from.


  1. .NET 4.7.2 is needed to run opencover

Submissions and Community Licence Agreement

You will be asked to agree to a CLA as part of the submission process; first pull request only and it's all automatic no printing and signing etc. You can read the agreement here - OpenCover CLA and you can read our Q&A on the wiki as to why.


Please review the wiki pages on how to use OpenCover and take particular interest in the Usage guide.


Please raise issues on GitHub, if you can repeat the issue then please provide a sample to make it easier for us to also repeat it and then implement a fix. Please do not hijack unrelated issues, I would rather you create a new issue than add noise to an unrelated issue.

Dropbox is very useful for sharing files alternatively you could create a gist.


All Original Software is licensed under the MIT Licence and does not apply to any other 3rd party tools, utilities or code which may be used to develop this application.

If anyone is aware of any licence violations that this code may be making please inform the developers so that the issue can be investigated and rectified.

Visual Studio Integration

The following add-in for visual studio can be used to run and view coverage results within the IDE

Integration Test support

OpenCover was initially created to support unit testing techniques such as TDD and tools like NUnit and MSTest. Over time others have found ways to use OpenCover for integration testing especially in tricky scenarios such as IIS and Windows Services. I'll put links here as to how people have achieved this however as they say YMMV (Your Mileage May Vary).

Mono support

It isn't, sorry - this tool uses the profiler API that is currently only available to .NET Frameworks running on the Windows platform.

IIS support

Please refer to the wiki - IIS Support

DNX support

Please refer to the wiki - DNX Support

Win8/Win10 Application Support

Not yet implemented. Sorry no user call/demand for it, I assume the WPF way of separating model and UI has led to people getting all they need from unit-tests; I know how that is how it works for me.

Service support

Please refer to the wiki - Service Support

Silverlight support

Please refer to the wiki - Silverlight support


You will need:

To build from the command line:

  1. Visual Studio VS2019 (Community Edition) with C#, C++, .Net Core
  2. .NET SDKs (
2.1.816 (* - LTS Version)
3.1.410 (* - LTS version)
5.0.301 (* - this is specified in the global.json)
  1. WiX 3.11 or later ( and Votive 2019 (
  2. Windows SDK 10 (10.0.18362.0) and .NET Framework Tools (

To build and run from within visual studio: 5. SpecFlow for Visual Studio 2017 ( 6. Microsoft .NET Framework 4.7.2 Developer Pack (

All other software should be included with this repository.

NANT scripts (encapsulated by the build.bat file) are used to build the project outside visual studio and will run all unit tests.

To build the code in 32-bit Debug mode just run Build in the root of the project folder.

To build a release package including installer, zip and nuget packages use

build create-release

Build Server

The OpenCover team is using Appveyor for automated building. It runs a staged equivalent of

build create-release

and stores all the information about tests, coverage and other build artefacts; you can use these builds if you want to be 'cutting' edge but support will be limited.

We have also suppied the appveyor.yml to make it easy for any forks to have their own builds on AppVeyor. If you send a pull-request the CI system will test your commits (which saves the team time if we do it ourselves)


The current OpenCover coverage (found by dogfooding OpenCover on its own tests) can be viewed here



For local viewing of the output from OpenCover start here.

Latest Drop as ZIP

No Git? Don't worry you can download the latest code as a zip file.


I would like to thank

  • AppVeyor for allowing free build CI services for Open Source projects,
  • Coveralls for allowing free services for Open Source projects,
  • NDepend for my NDepend licence - I don't use it nearly as much as I know I should do,
  • the guys at CodeBetter, Devlicious and Los Techies who orignally arranged my MSDN licence all those years ago without which I doubt I'd have been able to start OpenCover (now no longer needed as we can build OpenCover using the Community Editions),
  • the NextGenUG and their free swag from where I got lots of useful tools,

I would also like to thank my family, employers, colleagues and friends for all their support.