service.startAsync().awaitRunning();
    assertEquals(1, service.startUpCalled);
    assertEquals(Service.State.RUNNING, service.state());
    assertThat(service.transitionStates).containsExactly(Service.State.STARTING);
  }

  public void testStart_failed() {
    final Exception exception = new Exception("deliberate");
    TestService service =
        new TestService() {
          @Override

    service.startAsync().awaitRunning();
    assertEquals(1, service.startUpCalled);
    assertEquals(Service.State.RUNNING, service.state());
    assertThat(service.transitionStates).containsExactly(Service.State.STARTING);
  }

  public void testStart_failed() {
    final Exception exception = new Exception("deliberate");
    TestService service =
        new TestService() {
          @Override

      this.state = state;
    }

    @Override
    public void starting() {
      ServiceManagerState state = this.state.get();
      if (state != null) {
        state.transitionService(service, NEW, STARTING);
        if (!(service instanceof NoOpService)) {
          logger.get().log(Level.FINE, "Starting {0}.", service);
        }
      }
    }

    @Override
    public void running() {

      this.state = state;
    }

    @Override
    public void starting() {
      ServiceManagerState state = this.state.get();
      if (state != null) {
        state.transitionService(service, NEW, STARTING);
        if (!(service instanceof NoOpService)) {
          logger.get().log(Level.FINE, "Starting {0}.", service);
        }
      }
    }

    @Override
    public void running() {

    @Override
    protected void startUp() {
      assertFalse(startUpCalled);
      assertFalse(runCalled);
      assertFalse(shutDownCalled);
      startUpCalled = true;
      assertEquals(State.STARTING, state());
    }

    @Override
    protected void run() {
      assertTrue(startUpCalled);
      assertFalse(runCalled);
      assertFalse(shutDownCalled);
      runCalled = true;

 / {{{https://codehaus-plexus.github.io/plexus-containers/plexus-container-default/apidocs/org/codehaus/plexus/logging/Logger.html}Logger}}.

 Starting with Maven 3.1.0:

  *  Maven supports SLF4J API logging API too, ie {{{http://slf4j.org/apidocs/org/slf4j/LoggerFactory.html}LoggerFactory}} /
     {{{http://slf4j.org/apidocs/org/slf4j/Logger.html}Logger}},

    @Override
    protected void startUp() {
      assertFalse(startUpCalled);
      assertFalse(runCalled);
      assertFalse(shutDownCalled);
      startUpCalled = true;
      assertEquals(State.STARTING, state());
    }

    @Override
    protected void run() {
      assertTrue(startUpCalled);
      assertFalse(runCalled);
      assertFalse(shutDownCalled);
      runCalled = true;

### Single Container

If you have a simple setup, with a **single container** that then starts multiple **worker processes** (or also just one process), then you could run those previous steps in the same container, right before starting the process with the app.

### Base Docker Image

If you know perfectly how imports work, continue to the next section below.

///

A single dot `.`, like in:

```Python
from .dependencies import get_token_header
```

would mean:

* Starting in the same package that this module (the file `app/routers/items.py`) lives in (the directory `app/routers/`)...
* find the module `dependencies` (an imaginary file at `app/routers/dependencies.py`)...

///

## Previous Steps Before Starting

There are many cases where you want to perform some steps **before starting** your application.

For example, you might want to run **database migrations**.

But in most cases, you will want to perform these steps only **once**.

So, you will want to have a **single process** to perform those **previous steps**, before starting the application.