natsserver "github.com/nats-io/nats-server/v2/test"
)

func TestNatsConnPlain(t *testing.T) {
	opts := natsserver.DefaultTestOptions
	opts.Port = 14222
	s := natsserver.RunServer(&opts)
	defer s.Shutdown()

	clientConfig := &NATSArgs{
		Enable: true,
		Address: xnet.Host{
			Name:      "localhost",
			Port:      (xnet.Port(opts.Port)),
			IsPortSet: true,
		},
		Subject: "test",
	}

It is very simple and intuitive. It's designed to be easily extensible, and have modular components.

It has:

* Seriously impressive performance.
* WebSocket support.
* In-process background tasks.
* Startup and shutdown events.
* Test client built on HTTPX.
* CORS, GZip, Static Files, Streaming responses.
* Session and Cookie support.
* 100% test coverage.
* 100% type annotated codebase.
* Few hard dependencies.

    }

    @Test
    void testShutdown() {
        assertDoesNotThrow(() -> channelManager.shutdown());

        // Multiple shutdowns should be safe
        assertDoesNotThrow(() -> channelManager.shutdown());
    }

    @Test
    void testLoadBalancerAccess() {
        ChannelLoadBalancer balancer = channelManager.getLoadBalancer();

        startLatch.countDown();

        // Wait for completion
        assertTrue(endLatch.await(30, TimeUnit.SECONDS), "All threads should complete within timeout");
        executor.shutdown();

        // Then - Verify no exceptions occurred
        if (!exceptions.isEmpty()) {
            fail("Concurrent operations caused exceptions: " + exceptions.get(0));
        }

                assertEquals(numThreads * searchersPerThread, registeredCount.get());

            } finally {
                executor.shutdown();
                executor.awaitTermination(5, TimeUnit.SECONDS);
            }
        }
    }

    /**
     * Test that search operations can be performed while searchers are being registered.

      }
    }

  private val backend = TaskRunner.RealBackend(threadFactory)
  private val taskRunner = TaskRunner(backend)
  private val queue = taskRunner.newQueue()

  @AfterEach fun tearDown() {
    backend.shutdown()
  }

  @Test fun test() {
    val t1 = System.nanoTime() / 1e6

    val delays = mutableListOf(TimeUnit.MILLISECONDS.toNanos(1000), -1L)
    queue.schedule("task", TimeUnit.MILLISECONDS.toNanos(750)) {

    serializer = ExecutionSequencer.create();
    firstFuture = SettableFuture.create();
    firstCallable = new TestCallable(firstFuture);
  }

  @Override
  public void tearDown() throws Exception {
    executor.shutdown();
  }

  public void testCallableStartsAfterFirstFutureCompletes() {
    @SuppressWarnings({"unused", "nullness"})
    Future<?> possiblyIgnoredError = serializer.submitAsync(firstCallable, directExecutor());

    serializer = ExecutionSequencer.create();
    firstFuture = SettableFuture.create();
    firstCallable = new TestCallable(firstFuture);
  }

  @Override
  public void tearDown() throws Exception {
    executor.shutdown();
  }

  public void testCallableStartsAfterFirstFutureCompletes() {
    @SuppressWarnings({"unused", "nullness"})
    Future<?> possiblyIgnoredError = serializer.submitAsync(firstCallable, directExecutor());

    proceed.countDown()
    t1.join()
    assertThat(idle.get()).isTrue()
  }

  @Test
  fun executionRejectedImmediately() {
    val request = newRequest("http://a/1")
    executor.shutdown()
    client.newCall(request).enqueue(callback)
    callback.await(request.url).assertFailure(InterruptedIOException::class.java)
    assertThat(eventRecorder.recordedEventTypes())

```

⛔️ **Shell** form:

```Dockerfile
# ⛔️ Don't do this
CMD fastapi run app/main.py --port 80
```

Make sure to always use the **exec** form to ensure that FastAPI can shutdown gracefully and [lifespan events](../advanced/events.md) are triggered.

You can read more about it in the [Docker docs for shell and exec form](https://docs.docker.com/reference/dockerfile/#shell-and-exec-form).