dotnet-reportgenerator is not able to find any coverage.cobertura.xml when running inside Gitlab CI pipeline

Question

I want to generate a single coverage report for my C# project based on this tutorial

https://learn.microsoft.com/en-us/dotnet/core/testing/unit-testing-code-coverage

When starting a Gitlab CI pipeline with the following configuration

image: mcr.microsoft.com/dotnet/sdk:5.0

stages:
  - build
  - unit-tests

build:
  stage: build
  script:
    - dotnet build --output build
  artifacts:
    paths:
      - build

unit-tests:
  stage: unit-tests
  script:
    - |-
      dotnet test --no-build --output build --collect:"XPlat Code Coverage";
      
      dotnet tool install -g dotnet-reportgenerator-globaltool;

      reportgenerator -reports:'**/coverage.cobertura.xml' -targetdir:'CoverageReports' -reporttypes:'Cobertura';
  artifacts:
    reports:
      cobertura: CoverageReports/Cobertura.xml
  dependencies:
    - build

I get the following error

The report file pattern '**/coverage.cobertura.xml' is invalid. No matching files found.

When using ls to inspect the directory before running the reportgenerator command I can see that there are no matching files (although they should exist).

I would expect to have one coverage.cobertura.xml file per test project e.g.

• ...\myRepo\xUnitTestProject1\TestResults\380e65f7-48d5-468f-9cbc-550c8e0aeda8\coverage.cobertura.xml
• ...\myRepo\xUnitTestProject2\TestResults\c96c55f7-40d3-483e-a136-573615e3a9c3\coverage.cobertura.xml

---

My current solution:

It seems I have to run the build again. So I replaced this line

dotnet test --no-build --output build --collect:"XPlat Code Coverage";

with

dotnet test --collect:"XPlat Code Coverage";

Now it's working fine but an additional build seems to be redundant because I already created a build artifact...

---

So do you have any ideas how to improve the configuration so that I don't have to build a second time?

Answer 1

It seems like you could combine the two steps since dotnet test will also trigger a build. You would have build problems reported from the same stage as tests, but both have similar responses.

image: mcr.microsoft.com/dotnet/sdk:5.0

stages:
  - unit-tests


unit-tests:
  stage: unit-tests
  script:
    - |-
      dotnet test --output build --collect:"XPlat Code Coverage";
      
      dotnet tool install -g dotnet-reportgenerator-globaltool;

      reportgenerator -reports:'../coverage.cobertura.xml' -targetdir:'CoverageReports' -reporttypes:'Cobertura';
  artifacts:
    paths:
      - build
    reports:
      cobertura: CoverageReports/Cobertura.xml

---

Alternatively: Coverlet Collector depends on CoreCompile. But, the Global tool does not (since it isn't an msbuild task).

image: mcr.microsoft.com/dotnet/sdk:5.0

stages:
  - build
  - unit-tests

build:
  stage: build
  script:
    - dotnet build --output build
  artifacts:
    paths:
      - build

unit-tests:
  stage: unit-tests
  script:
    - |-
      dotnet test --no-build --output build --collect:"XPlat Code Coverage";

      dotnet tool install -g coverlet.console;

      dotnet tool install -g dotnet-reportgenerator-globaltool;

      coverlet /path/to/test-assembly.dll --target "dotnet" --targetargs "test /path/to/test-project --no-build";


      reportgenerator -reports:'../coverage.cobertura.xml' -targetdir:'CoverageReports' -reporttypes:'Cobertura';
  artifacts:
    reports:
      cobertura: CoverageReports/Cobertura.xml
  dependencies:
    - build

Coverlet's global tool also supports a --format cobertura option that may help to simplify this further.