Merge multiple coverage files inside Github Actions

Merge multiple coverage files inside Github Actions

Problem Statement

When you have multiple test projects in your solution and you want to merge the coverage reports of all the test projects into a single report.

Solution

Install dotnet tool dotnet-coverage which can merge all the coverage files into a single file.

dotnet tool install -g dotnet-coverage

Usage

Merge multiple coverage files

dotnet coverage merge --reports "path/to/coverage1.xml" "path/to/coverage2.xml" --output "path/to/merged.xml"

Merge all coverage files in a directory

You need to first set the output directory for all the tests to same folder. Then you can merge all the coverage files in that directory into one file. Which will be easier to upload to any coverage tool or using this single file we can generate HTML output.

dotnet test --collect:"XPlat Code Coverage" --results-directory "coverage-results"

dotnet coverage merge --reports "coverage-results/**/coverage.cobertura.xml" -f cobertura -o coverage-results/coverage.xml

Github Actions

- name: Install dotnet-coverage tool
  run: dotnet tool install -g dotnet-coverage

- name: Run tests and merge coverage files
  run: |
    dotnet test --collect:"XPlat Code Coverage" --results-directory "coverage-results"
    dotnet coverage merge --reports "coverage-results/**/coverage.cobertura.xml" -f cobertura -o coverage-results/coverage.xml