In a previous article, titled Building a Build Server – Executing Unit Tests as Part of the Build, we explored the details of setting up automatic unit test execution.
Automatically executing unit tests during the build gives us confidence that our code is correct. Especially if we also:
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Write good unit tests,
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Do not ignore when the tests are failing,
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And our codebase is covered in a relevant percentage.
So, how do we know what is covered and what is not? Well, this article is just about that: getting a report about which lines were executed during the execution of the unit tests. In this article, we are going to add capability to our Jenkins server to assemble report on test coverage. This test coverage report is high in quality because it contains even branch coverage information, which is ignored by some commercial coverage tools too.
Installing the necessary tools
OpenCover
OpenCover is a tool for collecting coverage information during the execution. To collect coverage information from the unit tests, we are going to execute the unit tests through this application. To install OpenCover, execute the following commands from the Cygwin terminal:
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mkdir /tmp/OpenCover cd /tmp/OpenCover wget https://github.com/OpenCover/opencover/releases/download/4.6.519/opencover.4.6.519.zip unzip opencover.4.6.519.zip rm opencover.4.6.519.zip cd /cygdrive/c mv /tmp/OpenCover /cygdrive/c icacls OpenCover /T /Q /C /RESET |
To allow OpenCover to monitor other the programs run through it, its two profiler DLL must be registered into the system. To do so, execute the following commands from a Windows command prompt running as an Administrator:
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C: cd C:\OpenCover regsvr32 /s x86\OpenCover.Profiler.dll regsvr32 /s x64\OpenCover.Profiler.dll |
ReportGenerator
Currently, OpenCover does not have the capability to generate nice looking reports, just a coverage XML. Here comes ReportGenerator into play. ReportGenerator will take the coverage data represented in XML format and transform it into a highly usable documentation composed from HTML pages. Installation of ReportGenerator can be achieved by executing the following commands from the Cygwin terminal:
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mkdir /tmp/ReportGenerator cd /tmp/ReportGenerator unzip ReportGenerator_2.5.6.0.zip rm ReportGenerator_2.5.6.0.zip cd /cygdrive/c mv /tmp/ReportGenerator /cygdrive/c icacls ReportGenerator /T /Q /C /RESET |
Integrating code coverage report into Jenkins
The following Jenkins build project will check out the demo repository located at https://github.com/atzimler/CoverageTest.git, build it and create report of the unit test coverage on the codebase:
Source Code Management
Use Git source code management with
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Repositories |
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Repository URL |
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Branches to build |
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Branch specifier (blank for ‘any’) |
*/master |
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Repository browser: |
(Auto) |
Build
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Execute Windows batch command |
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Command |
cd CoverageTests\bin\Debug C:\OpenCover\OpenCover.Console.exe -target:C:\NUnit.org\nunit3-console.exe -targetargs:CoverageTests.dll -register:user -output:TestCoverage.xml C:\ReportGenerator\ReportGenerator.exe -reports:TestCoverage.xml -targetdir:..\..\..\CoverageReport Please note: Each paragraph here is one line of command. In case you are copy-pasting the code it should be ok, but if you manually copying it, please don’t insert spaces where paragraph lines are breaking. |
Post-build Actions
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Archive the artifacts |
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Files to archive |
CoverageReport/** |
After the project has been built, we can find the coverage test under the Last Successful Artifacts sections, CoverageReport/index.htm.
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thanks your article is really helpful