# Run Angular tests in a container


## Prerequisites

Complete all the previous sections of this guide, starting with [Containerize Angular application](/guides/angular/run-tests/containerize/).

## Overview

Testing is a critical part of the development process. In this section, you'll learn how to:

- Run Jasmine unit tests using the Angular CLI inside a Docker container.
- Use Docker Compose to isolate your test environment.
- Ensure consistency between local and container-based testing.


The `docker-angular-sample` project comes pre-configured with Jasmine, so you can get started quickly without extra setup.

---

## Run tests during development

The `docker-angular-sample` application includes a sample test file at the following location:

```console
$ src/app/app.component.spec.ts
```

This test uses Jasmine to validate the AppComponent logic.

### Step 1: Update compose.yaml

Add a new service named `angular-test` to your `compose.yaml` file. This service allows you to run your test suite in an isolated, containerized environment.

```yaml {hl_lines="22-26",linenos=true}
services:
  angular-dev:
    build:
      context: .
      dockerfile: Dockerfile.dev
    ports:
      - "5173:5173"
    develop:
      watch:
        - action: sync
          path: .
          target: /app

  angular-prod:
    build:
      context: .
      dockerfile: Dockerfile
    image: docker-angular-sample
    ports:
      - "8080:8080"

  angular-test:
    build:
      context: .
      dockerfile: Dockerfile.dev
    command: ["npm", "run", "test"]

```

The angular-test service reuses the same `Dockerfile.dev` used for [development](/guides/angular/run-tests/develop/) and overrides the default command to run tests with `npm run test`. This setup ensures a consistent test environment that matches your local development configuration.


After completing the previous steps, your project directory should contain the following files:

```text
├── docker-angular-sample/
│ ├── Dockerfile
│ ├── Dockerfile.dev
│ ├── .dockerignore
│ ├── compose.yaml
│ ├── nginx.conf
│ └── README.Docker.md
```

### Step 2: Run the tests

To execute your test suite inside the container, run the following command from your project root:

```console
$ docker compose run --rm angular-test
```

This command will:
- Start the `angular-test` service defined in your `compose.yaml` file.
- Execute the `npm run test` script using the same environment as development.
- Automatically removes the container after tests complete, using the [`docker compose run --rm`](/reference/cli/docker/compose/run/) command.

You should see output similar to the following:

```shell
Test Suites: 1 passed, 1 total
Tests:       3 passed, 3 total
Snapshots:   0 total
Time:        1.529 s
```

> [!NOTE]
> For more information about Compose commands, see the [Compose CLI
> reference](/reference/cli/docker/compose/).

---

## Summary

In this section, you learned how to run unit tests for your Angular application inside a Docker container using Jasmine and Docker Compose.

What you accomplished:
- Created a `angular-test` service in `compose.yaml` to isolate test execution.
- Reused the development `Dockerfile.dev` to ensure consistency between dev and test environments.
- Ran tests inside the container using `docker compose run --rm angular-test`.
- Ensured reliable, repeatable testing across environments without depending on your local machine setup.

---

## Related resources

Explore official references and best practices to sharpen your Docker testing workflow:

- [Dockerfile reference](/reference/dockerfile/) – Understand all Dockerfile instructions and syntax.
- [Best practices for writing Dockerfiles](/develop/develop-images/dockerfile_best-practices/) – Write efficient, maintainable, and secure Dockerfiles.
- [Compose file reference](/compose/compose-file/) – Learn the full syntax and options available for configuring services in `compose.yaml`.  
- [`docker compose run` CLI reference](/reference/cli/docker/compose/run/) – Run one-off commands in a service container.
---

## Next steps

Next, you’ll learn how to set up a CI/CD pipeline using GitHub Actions to automatically build and test your Angular application in a containerized environment. This ensures your code is validated on every push or pull request, maintaining consistency and reliability across your development workflow.