}

  @Test
  public void addNode_newNode() {
    assume().that(graphIsMutable()).isTrue();

    assertThat(graphAsMutableGraph.addNode(N1)).isTrue();
    assertThat(graph.nodes()).contains(N1);
  }

  @Test
  public void addNode_existingNode() {
    assume().that(graphIsMutable()).isTrue();

    addNode(N1);

    assertThat(e).hasMessageThat().contains(ERROR_REUSE_EDGE);
  }

  @Test
  public void addEdge_parallelSelfLoopEdge_notAllowed() {
    assume().that(graphIsMutable()).isTrue();
    assume().that(network.allowsSelfLoops()).isTrue();
    assume().that(network.allowsParallelEdges()).isFalse();

    addEdge(N1, N1, E11);
    IllegalArgumentException e =
        assertThrows(

  }

  @Test
  public void addNode_newNode() {
    assume().that(graphIsMutable()).isTrue();

    assertThat(graphAsMutableGraph.addNode(N1)).isTrue();
    assertThat(graph.nodes()).contains(N1);
  }

  @Test
  public void addNode_existingNode() {
    assume().that(graphIsMutable()).isTrue();

    addNode(N1);

  @BeforeEach
  fun setUp() {
    // Default after JDK 14, but we are avoiding tests that assume special setup.
    // System.setProperty("jdk.tls.client.enableSessionTicketExtension", "true")
    // System.setProperty("jdk.tls.server.enableSessionTicketExtension", "true")

    // IllegalStateException: Cannot resume session and session creation is disabled
    platform.assumeNotBouncyCastle()
  }

  @Test

  }

  /*
   * We override the toArray methods for two reasons:
   *
   * 1. Both superclass toArray methods assume that size() gives a correct answer, while our size()
   * might not (and the answer might change while we're building the array).
   *
   * TODO: cpovirk - Is this an issue anywhere anymore? It looks to have been fixed for Java 8
   * (https://bugs.openjdk.org/browse/JDK-7121314) and before Lollipop

</div>

This means that it will **always have a value**, it's just that sometimes the value could be `None` (or `null` in JSON).

That means that, clients using your API don't have to check if the value exists or not, they can **assume the field will always be there**, but just that in some cases it will have the default value of `None`.

The way to describe this in OpenAPI, is to mark that field as **required**, because it will always be there.

                    int patch = Integer.parseInt(parts[2]);
                    return patch > 0;
                }
            }
        } catch (NumberFormatException e) {
            // If we can't parse it, assume it's not newer
            return false;
        }

        return false;
    }

    /**
     * Checks if a model version is greater than or equal to a target version.
     *

So, let's say you have a frontend running in your browser at `http://localhost:8080`, and its JavaScript is trying to communicate with a backend running at `http://localhost` (because we don't specify a port, the browser will assume the default port `80`).

      int jellyBean =
          (int) Class.forName("android.os.Build$VERSION_CODES").getField("JELLY_BEAN").get(null);
      /*
       * I assume that this check can't fail because JELLY_BEAN will be present only if we're
       * running under Jelly Bean or higher. But it seems safest to check.
       */
      if (version < jellyBean) {

/// note

Notice that you have to return the image using a `FileResponse` directly.

///

/// info

Unless you specify a different media type explicitly in your `responses` parameter, FastAPI will assume the response has the same media type as the main response class (default `application/json`).