JetBrains dotCover is a .NET unit test runner and code coverage tool. dotCover lets us analyze how much of our .NET application code is actually being tested. By measuring method calls during unit tests or when running the application manually, dotCover shows us which statements were covered and which were not.
dotCover integrates into Visual Studio 2010, 2012, 2013, 2015, 2017, and 2019. After installing dotCover with or without any other ReSharper Ultimate tools and opening Visual Studio, you will find dotCover commands under the and in the main menu. From these menus, you can execute various commands available in dotCover.
Unit testing and code coverage
The most basic scenario of using dotCover is measuring how much of your code do tests cover. Baseline conditions are as follows. You have a solution opened in Visual Studio. Code in the solution is covered with some unit tests. The task is to understand how much of the code is covered.
To analyze coverage of unit tests in a solution
Choose Unit Test Explorer tool window. Here you can take a look at how many tests are there in the solution.from the main menu. This will open the
In the Unit Test Explorer window, select the tests whose coverage you want to analyze. If you want to analyze all tests, select the top-level node in the tree. Note that you can limit coverage scope by using coverage filters.
Click Cover Unit Tests . This will run a normal unit tests session but dotCover will collect coverage data in the background. Test results will be shown in real time in the newly opened Unit Test Sessions window. Coverage results (how tests cover particular classes and methods in your code) will be shown in the Unit Test Coverage tool window.
If you want to see what tests exactly cover a particular class or method, select it in the Unit Test Coverage window and in the context menu choose Show Covering Tests.
Visualize code coverage by clicking the Highlight code button. By default, coverage and test results are shown by markers in the left gutter of the Visual Studio editor: a marker is red if any tests related to the current statement are failing, green if all tests are passing, and grey if there are no tests covering this statement.
The Unit Test Coverage window contains one more very useful metric. After you click Hot Spots, it will show you a "cloud" of potentially risky classes: the classes that have high cyclomatic complexity but are poorly covered with tests.
Coverage of applications
dotCover enables us to calculate code coverage for a specific use-case scenario. Hitting Ctrl+Alt+K P or choosing in the menu launches our solution's startup project under dotCover control. Alternatively, Ctrl+Alt+K K or enables us to specify the application to calculate code coverage for.
Next, we can run our application and work through a use-case scenario and tell dotCover to get a snapshot once completed. As long as the tested application runs under dotCover control, the controller dialog is displayed where you can click Get Snapshot and inspect which lines of code were covered when we worked with the tested application.
Filtering coverage results
Code coverage results can be cluttered with infrastructure code or projects that we are not interested in inspecting. We can exclude specific nodes by right-clicking them and choosing Exclude and Create Coverage Filter:
Excluding item and creating a corresponding runtime coverage filter will tell dotCover not to cover the item next time we run coverage analysis.