Code coverage report generation for dotnet core applications

In "Working Effectively with Legacy Code" Michael Feathers introduced a definition of legacy code as code without tests, since a code without tests is difficult to maintain, extend and evolve. It doesn't matter if you are using the latest technologies, if you don't test your code, it will hard to change without breaking anything, which will make it rigid and difficult to maintain. Remember that unit tests are the base in the testing pyramid.

In order to ensure that you are covering with unit tests the most important part of our application, code coverage can be helpful to detect where you have lack of tests.

Code coverage is a tool offered by products like ReSharper or the Enterprise version of Visual Studio. However, these products are not free and you might not want to pay for this essential feature.

But if you are working with dotnet core, it is quite easy to get a code coverage report thanks to ReportGenerator package.

In order to generate your tests, first you need to install ReportGenerator in your machine with this command:

dotnet tool install -g dotnet-reportgenerator-globaltool

Then you can run your tests and create coverage reports by using this command:

dotnet test --collect:"XPlat Code Coverage"
Finally, you can use reportgenerator command to generate a report with actual coverage in your code:
reportgenerator "-reports:./**/coverage.cobertura.xml" "-targetdir:./coverage" "-reporttypes:Html"
And that is all. Handy, right?. In addition, since I like to make it even more easy to execute, I've created a .bat file, which execute my tests, generates a coverage report, and opens chrome to display the report. As a result, I can update my coverage report with double-click. This is the code for my script:
dotnet test --collect:"XPlat Code Coverage"
reportgenerator "-reports:./**/coverage.cobertura.xml" "-targetdir:./coverage" "-reporttypes:Html"
start chrome ./coverage/index.html
In order to provide an example, I've created this GitHub project with some tests: https://github.com/albertocorrales/code-coverage-report
 
When I execute my coverage.bat script, my browser is automatically opened displaying this coverage report.
 

In our report we can see the coverage for each of our files and different metrics like line coverage, branch coverage, etc.
 
I hope you found helpful this article.
 
 

Comments

Post a Comment

Popular posts from this blog

Building Micro-Frontends with Single-Spa

Image
Introduction Micro-services architecture is becoming trendy since it is a suitable option many projects, specially those that are complex and we want to be able spilt our business logic into different services that can be built and deliver independently. In spite of the fact that micro-services architectures are more complex, they increase the resilience of your system and increase the time-to-market delivery, which can be crucial for many companies. But it is not all about services and backend. With the introduction of single page applications (SPAs), we can build fully-functional user interfaces that can work independently in the browser. And here we should ask ourselves the same questions as for backend applications: Is my SPA becoming a huge monolith? Would I like to deliver functional modules independently? If you using micro-services, is there a relation between my services and your UI? Do we want to have functional teams that can deliver new features (frontend+backend) independe
Read more

Why you should migrate your old csproj to SDK format

Image
Introduction  With the introduction of Visual Studio 2017, the format used for csproj was updated including several advantages. This new format will be used when you create a new .Net Core project or .Net Standard library. In spite of the fact that VS2017 continues supporting old csproj format, you can migrate your old projects to SDK format. As a result, you will have the following benefits: Cleaner csproj files. With new format, a lot of things can be omitted, so your csproj files will be cleaner. Files are included using a wildcard , instead of including every single file.  Solution project references are simplier . NuGet reference packages as PackageReferences , so you won't need packages.config and you will be able to use wildcard in your references (for example, 1.0.*). NuGet package definition as a part of the project file. You won't need more nuspec files. Definition of AssemblyInfo attributes in csproj , you won't need more AssemblyInfo.cs files. In ad
Read more

AWS assuming role + MFA with pulumi (and other applications)

Image
Introduction In AWS, managing your IAM in a centralized account is a good practice, so then you can assume a role to access to other accounts without need of duplicating users. You can find more info about this approach in this article . In addition, for security reasons, it is highly recommended to enable MFA (Multi-factor Authentication), so you need a device to generate a temporary code to get access. In the image below it is showed how assume role with MFA works, but you also have an article about MFA in this link . This approach is really useful and most of the configuration can be automated with pulumi (or other providers like terraform or CloudFormation). And once it is configured, you can switch your role and get access to other accounts with a few clicks.  However, when it comes to external software such us pulumi, getting access assuming a role and using MFA might not be too straightforward. In this article we will see how this can be configured and how we can easily refresh
Read more