## Overriding dependencies during testing { #overriding-dependencies-during-testing }

There are some scenarios where you might want to override a dependency during testing.

You don't want the original dependency to run (nor any of the sub-dependencies it might have).

### Suggest solutions { #suggest-solutions }

* After being able to understand the question, you can give them a possible **answer**.

* In many cases, it's better to understand their **underlying problem or use case**, because there might be a better way to solve it than what they are trying to do.

    eventSource: EventSource,
    response: Response,
  ) {
  }

  /**
   * Invoked when a new event has been sent to the client.
   *
   * @param id The `id` line of the event, might be null.
   * @param type The `event` line of the event, might be null.
   * @param data The `data` line of the event.
   */
  open fun onEvent(
    eventSource: EventSource,
    id: String?,
    type: String?,
    data: String,
  ) {
  }

		t.Errorf("%s: Expected IsTruncated to be `false`, but instead found it to be `%v`", instanceType, result.IsTruncated)
	}

	uploadContent := "The specified multipart upload does not exist. The upload ID might be invalid, or the multipart upload might have been aborted or completed."
	var opts ObjectOptions
	// check before paging occurs.
	for i := range 5 {
		key := "obj" + strconv.Itoa(i)

                return message.contains("connection reset") || message.contains("network unreachable")
                        || message.contains("host unreachable") || message.contains("timeout");
            }
            return true; // Generic socket errors might be recoverable
        }

        // Generic IO exceptions might be recoverable

points to the public IP address where each cluster might be accessible, this is unique for each cluster.

NOTE: `mybucket` only exists on one cluster either `cluster1` or `cluster2` this is random and
is decided by how `domain.com` gets resolved, if there is a round-robin DNS on `domain.com` then
it is randomized which cluster might provision the bucket.

### 3. Test your setup

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[22] *}

/// tip

All this might seem contrived. And it might not be very clear how is it useful yet.

These examples are intentionally simple, but show how it all works.

In the chapters about security, there are utility functions that are implemented in this same way.

### Disable Response Model { #disable-response-model }

Continuing from the example above, you might not want to have the default data validation, documentation, filtering, etc. that is performed by FastAPI.

But you might want to still keep the return type annotation in the function to get the support from tools like editors and type checkers (e.g. mypy).

* **Modify some DNS records**.
    * For this, the renewal program needs to support the APIs of the DNS provider, so, depending on the DNS provider you are using, this might or might not be an option.
* **Run as a server** (at least during the certificate acquisition process) on the public IP address associated with the domain.
    * As we said above, only one process can be listening on a specific IP and port.

    }
    assertNull(
        "The array element immediately following the end of the collection should be nulled",
        array[getNumElements()]);
    // array[getNumElements() + 1] might or might not have been nulled
  }

  @CollectionFeature.Require(KNOWN_ORDER)
  public void testToArray_oversizedArray_ordered() {
    E[] array = getSubjectGenerator().createArray(getNumElements() + 2);