// more time has passed than the timeout value and return false.
func (dm *DRWMutex) GetLock(ctx context.Context, cancel context.CancelFunc, id, source string, opts Options) (locked bool) {
	isReadLock := false
	return dm.lockBlocking(ctx, cancel, id, source, isReadLock, opts)
}

// RLock holds a read lock on dm.
//
// If one or more read locks are already in use, it will grant another lock.

{!../../docs_src/templates/static/styles.css!}
```

And because you are using `StaticFiles`, that CSS file would be served automatically by your **FastAPI** application at the URL `/static/styles.css`.

## More details

			expected: "example.com, [fd00:10:96::7fc7]",
		},
		{
			desc:     "test with more domains",
			domains:  []string{"example.com", "example.com:8080", "www.example.com", "www.example.com:8080", "[fd00:10:96::7fc7]", "[fd00:10:96::7fc7]:8080"},
			expected: "example.com, www.example.com + 1 more...",
		},
	}

	for _, tt := range tests {
		t.Run(tt.desc, func(t *testing.T) {

    /**
     * Returns a new immutable array. The builder can continue to be used after this call, to append
     * more values and build again.
     *
     * <p><b>Performance note:</b> the returned array is backed by the same array as the builder, so
     * no data is copied as part of this step, but this may occupy more memory than strictly
     * necessary. To copy the data to a right-sized backing array, use {@code .build().trimmed()}.
     */

Let's continue from the previous example. We wanted to **annotate the function with one type**, but we wanted to be able to return from the function something that actually includes **more data**.

We want FastAPI to keep **filtering** the data using the response model. So that even though the function returns more data, the response will only include the fields declared in the response model.

    /**
     * Returns a new immutable array. The builder can continue to be used after this call, to append
     * more values and build again.
     *
     * <p><b>Performance note:</b> the returned array is backed by the same array as the builder, so
     * no data is copied as part of this step, but this may occupy more memory than strictly
     * necessary. To copy the data to a right-sized backing array, use {@code .build().trimmed()}.
     */

For this, you use the `TestClient` in a `with` statement, connecting to the WebSocket:

```Python hl_lines="27-31"
{!../../docs_src/app_testing/tutorial002.py!}
```

/// note

For more details, check Starlette's documentation for <a href="https://www.starlette.io/testclient/#testing-websocket-sessions" class="external-link" target="_blank">testing WebSockets</a>.

# Test Client - `TestClient`

You can use the `TestClient` class to test FastAPI applications without creating an actual HTTP and socket connection, just communicating directly with the FastAPI code.

Read more about it in the [FastAPI docs for Testing](https://fastapi.tiangolo.com/tutorial/testing/).

You can import it directly from `fastapi.testclient`:

```python
from fastapi.testclient import TestClient
```

# About

# Resources