Analyze .NET code coverage

JetBrains dotCover is a .NET unit testing and code coverage tool that works right in Visual Studio, helps you know to what extent your code is covered with unit tests, provides great ways to visualize code coverage, and is ready for continuous integration.

Running and managing unit tests

dotCover comes bundled with a unit test runner that it shares with another JetBrains tool for .NET developers, ReSharper. The runner works in Visual Studio, allows managing unit tests through sessions, and supports multiple unit testing frameworks, namely MSTest, NUnit, xUnit (all out of the box) and MSpec (via a plug-in).

Continuous testing

dotCover supports continuous testing: a modern unit testing workflow whereby dotCover figures out on-the-fly which unit tests are affected by your latest code changes, and automatically re-runs the affected tests for you. Based on your preferences, dotCover can run affected tests on saving a file, on building your solution or soon as you explicitly tell dotCover to do so. The continuous testing mode can be switched on for any unit test session: this way you can choose which tests you want to run continuously and which to run in a traditional way.

Unit test coverage

A major use case of dotCover is analyzing unit test coverage — that is, finding out which parts of application business logic are covered with unit tests, and which are not. Along with unit test run results, dotCover displays a coverage tree showing how thoroughly a particular project, namespace, type, or type member is covered with unit tests.

Coverage highlighting in Visual Studio

To visualize coverage data, dotCover can highlight lines of code right in Visual Studio code editor. There's an option to switch between highlighting markers and colored background or to display both. Note that highlighting shows not only covered and uncovered code but the results of the covering unit tests as well. Green color means that tests pass while red color indicates that at least one test that covers the statement fails. Grey color shows uncovered code.

Navigation to covering tests

dotCover provides a command (and a keyboard shortcut) to detect which tests cover a particular location in code, be it a class, method, or property. You can invoke the command from Visual Studio text editor or from dotCover's Coverage Tree view. You can navigate from a pop-up that lists covering tests to any of these tests. Additionally, you can instantly run them or add to an existing unit test session.

Hot Spots view

The Hot Spots view was designed to help you identify the riskiest methods in your solution. Hot Spots are calculated in terms of high cyclomatic complexity and low unit test coverage of the methods.

Remote code coverage

You can run coverage analysis of unit tests on a remote machine and have results served back to your local computer. As soon as you start coverage analysis, dotCover sends binaries and the list of tests to be executed to a remote server. All calculations are executed by the server, and the coverage snapshot is then sent back to your machine. You can then examine coverage results in the same way you do following a local coverage run.

Coverage filters

Sometimes, you don't want to know coverage data solution-wide. For example, you may not be interested in coverage statistics for code marked with ObsoleteAttribute or a specific legacy project. In this case, you can set global or solution-specific coverage filters based on project, namespace, type, or type member names. Attribute filters are also available that restrict gathering coverage information to code marked (or not marked) with certain attributes.

Multiple report formats

dotCover helps process coverage data the way you need. Exporting to several formats, including HTML, XML, JSON, and XML for NDepend enables you to share coverage reports with the rest of the team or pass coverage information to external services.

Coverage analysis as part of Continuous Integration

dotCover is a great fit with Continuous Integration servers, most prominently JetBrains' own product, TeamCity. First of all, via TeamCity add-in to Visual Studio, dotCover is able to obtain coverage data from a TeamCity server — without running coverage analysis on a local machine. On the other hand, dotCover coverage analysis engine is bundled with into a free version of TeamCity, which helps schedule coverage runs as part of the Continuous Integration process and generate server-side coverage reports. TeamCity understands the output of dotCover console runner and highlights its errors and warnings in the build log.