Running Tests in Docker

When running tests inside Docker containers, you need to extract coverage data from the container to upload it to Qlty. This guide covers two common approaches: using volume mounts and using docker cp.

Method 1: Volume Mounting

Volume mounting is the simplest approach where you mount your project directory into the container, allowing coverage files to be written directly to your host filesystem.

GitHub Actions Example

name: Main
on:
    push:
        branches: [main]
    pull_request:

permissions:
    contents: read
    id-token: write

jobs:
    test:
        runs-on: ubuntu-latest
        steps:
            - name: Checkout repo
              uses: actions/checkout@v4

            - name: Set up Docker Buildx
              uses: docker/setup-buildx-action@v3

            - name: Build Docker image
              run: docker build -t myapp-test .

            - name: Run tests in Docker
              run: |
                  docker run --rm \
                    -v "$(pwd)":/app \
                    -w /app \
                    myapp-test \
                    npm test -- --coverage

            - name: Check coverage file exists
              run: test -f coverage/lcov.info

            - name: Upload coverage to Qlty
              uses: qltysh/qlty-action/coverage@v2
              with:
                  oidc: true
                  files: coverage/lcov.info

Key Points for Volume Mounting

Mount your current directory ($(pwd)) to the container’s working directory
Use --rm to automatically remove the container after tests complete
Coverage files are written directly to your host filesystem
Works with any coverage format supported by Qlty

Method 2: Docker Copy

When you can’t use volume mounts (due to security restrictions or container design), you can copy coverage files out of the container after tests complete.

GitHub Actions Example

name: Main
on:
    push:
        branches: [main]
    pull_request:

permissions:
    contents: read
    id-token: write

jobs:
    test:
        runs-on: ubuntu-latest
        steps:
            - name: Checkout repo
              uses: actions/checkout@v4

            - name: Set up Docker Buildx
              uses: docker/setup-buildx-action@v3

            - name: Build Docker image
              run: docker build -t myapp-test .

            - name: Run tests in Docker (retain container)
              run: |
                  docker run --name test-container \
                    -w /app \
                    myapp-test \
                    npm test -- --coverage

            - name: Copy coverage files out of container
              run: |
                  docker cp test-container:/app/coverage/lcov.info coverage.lcov

            - name: Cleanup container
              run: docker rm test-container

            - name: Check coverage file exists
              run: test -f coverage.lcov

            - name: Upload coverage to Qlty
              uses: qltysh/qlty-action/coverage@v2
              with:
                  oidc: true
                  files: coverage.lcov

Key Points for Docker Copy

Don’t use --rm flag so the container persists after tests
Use --name to give the container a predictable name
Copy files using docker cp container_name:/path/to/file destination
Clean up the container manually after copying files

Alternative CI Providers

Using Coverage Tokens

If you’re not using GitHub Actions with OIDC, replace the upload step with a coverage token:

- name: Upload coverage to Qlty
  uses: qltysh/qlty-action/coverage@v2
  with:
      token: ${{ secrets.QLTY_COVERAGE_TOKEN }}
      files: coverage/lcov.info

Manual CLI Upload

For other CI providers, install the Qlty CLI and upload manually:

# After extracting coverage files from Docker
curl https://qlty.sh | sh
qlty coverage publish coverage/lcov.info

For some CI providers you may have to add --override-commit-sha and --override-branch flags with commit SHA and branch names.

# After extracting coverage files from Docker
curl https://qlty.sh | sh
qlty coverage publish coverage/lcov.info --override-commit-sha <COMMIT_SHA> --override-branch <BRANCH_NAME>

Multiple Coverage Files

If your Docker container generates multiple coverage files, you can upload them all:

Volume Mount Approach

- name: Upload coverage to Qlty
  uses: qltysh/qlty-action/coverage@v2
  with:
      oidc: true
      files: |
          coverage/unit.lcov
          coverage/integration.lcov

Docker Copy Approach

- name: Copy multiple coverage files
  run: |
    docker cp test-container:/app/coverage/unit.lcov unit.lcov
    docker cp test-container:/app/coverage/integration.lcov integration.lcov

Path Fixing

When running tests in Docker, file paths in coverage reports might not match your repository structure. Use path fixing options:

- name: Upload coverage to Qlty
  uses: qltysh/qlty-action/coverage@v2
  with:
      oidc: true
      files: coverage/lcov.info
      strip-prefix: /app/

Or with the CLI:

qlty coverage publish --strip-prefix=/app/ coverage/lcov.info

Troubleshooting

Coverage File Not Found

Ensure your test command actually generates coverage files
Check that the coverage output directory matches your copy/mount paths
Verify file permissions allow reading from the container

Path Mismatches

Use --strip-prefix to remove container-specific path prefixes
Use --add-prefix if you need to add a path prefix
Check that source paths in coverage reports match your repository structure

Container Cleanup Issues

Always clean up named containers when using docker cp
Use docker rm -f container_name to force removal if needed
Consider using --rm with volume mounts to avoid cleanup

Getting Started

Coverage In Your Workflow

Concepts

Features

Advanced Configuration

Reference

Running Tests in Docker

Method 1: Volume Mounting

GitHub Actions Example

Key Points for Volume Mounting

Method 2: Docker Copy

GitHub Actions Example

Key Points for Docker Copy

Alternative CI Providers

Using Coverage Tokens

Manual CLI Upload

Multiple Coverage Files

Volume Mount Approach

Docker Copy Approach

Path Fixing

Troubleshooting

Coverage File Not Found

Path Mismatches

Container Cleanup Issues

See Also

​Method 1: Volume Mounting

​GitHub Actions Example

​Key Points for Volume Mounting

​Method 2: Docker Copy

​GitHub Actions Example

​Key Points for Docker Copy

​Alternative CI Providers

​Using Coverage Tokens

​Manual CLI Upload

​Multiple Coverage Files

​Volume Mount Approach

​Docker Copy Approach

​Path Fixing

​Troubleshooting

​Coverage File Not Found

​Path Mismatches

​Container Cleanup Issues

​See Also

Method 1: Volume Mounting

GitHub Actions Example

Key Points for Volume Mounting

Method 2: Docker Copy

GitHub Actions Example

Key Points for Docker Copy

Alternative CI Providers

Using Coverage Tokens

Manual CLI Upload

Multiple Coverage Files

Volume Mount Approach

Docker Copy Approach

Path Fixing

Troubleshooting

Coverage File Not Found

Path Mismatches

Container Cleanup Issues

See Also