Test coverage reports with docker

Nick Chapsas has made an excellent video that explains how to collect the code coverage. To enhance our development experience, we aim to automate the process and visualize the test coverage report using Docker.

Here is an example of a Dockerfile:

# Use the official .NET SDK image to build the app and run tests
FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build

# Set the working directory
WORKDIR /app

# Copy the project files to the working directory
COPY . .

# Restore the project dependencies
RUN dotnet restore

# Run tests and collect code coverage
RUN dotnet test --collect:"XPlat Code Coverage" --results-directory ./testresults

# Install reportgenerator tool
RUN dotnet tool install -g dotnet-reportgenerator-globaltool

# Add the tool to the PATH
ENV PATH="${PATH}:/root/.dotnet/tools"

# Generate the HTML report
RUN reportgenerator -reports:"./testresults/*/coverage.cobertura.xml" -targetdir:coverage_report -reporttypes:Html

# Use the official Nginx image to serve the report
FROM nginx:alpine

# Copy the generated HTML report from the build stage
COPY --from=build /app/coverage_report /usr/share/nginx/html

# Expose port 80
EXPOSE 80

# Start Nginx server
CMD ["nginx", "-g", "daemon off;"]

Then the docker-compose.yml may look like the following:

name: date-extensions-test 
services:
  coverage-report:
    container_name: date-extensions-coverage-report
    build:
        context: .
        dockerfile: ./tests/DateExtensions.UnitTests/Dockerfile
    ports:
      - "7271:80"

The full example is accessible on GitHub.