You can collect coverage information from .NET managed code during execution of NUnit tests by running the built-in Run NUnit Tests with Coverage test configuration. For example:
dottestcli.exe -solution "C:\Devel\FooSolution\FooSolution.sln" -config "builtin://Run NUnit Tests with coverage" -report "C:\Report"
See Unit Testing for information about setting up and executing unit tests.
