fail();
    } catch (RuntimeException expected) {
      assertEquals(RUNTIME_EXCEPTION, expected);
    }
  }

  public void testGetUnchecked_Error() {
    try {
      getUnchecked(ERROR_FUTURE);
    } catch (Error expected) {
      assertEquals(ERROR, expected);
      return;
    }
    fail();
  }

        };
    addCallback(f, callback, directExecutor());
    f.cancel(true);
  }

  public void testThrowErrorFromGet() {
    Error error = new AssertionError("ASSERT!");
    ListenableFuture<String> f = UncheckedThrowingFuture.throwingError(error);
    MockCallback callback = new MockCallback(error);
    addCallback(f, callback, directExecutor());
  }

  public void testRuntimeExceptionFromGet() {

  private static final int EDGE_COUNT = 20;
  // TODO(user): Consider adding both error messages from here and {@link AbstractNetworkTest}
  // in one class (may be a utility class for error messages).
  private static final String ERROR_PARALLEL_EDGE = "connected by a different edge";
  private static final String ERROR_NEGATIVE_COUNT = "is non-negative";
  private static final String ERROR_ADDED_PARALLEL_EDGE =
      "Should not be allowed to add a parallel edge.";

   * writer each time it is called.
   *
   * <p>The caller is responsible for ensuring that the returned writer is closed.
   *
   * @throws IOException if an I/O error occurs while opening the writer
   */
  public abstract Writer openStream() throws IOException;

  /**
   * Opens a new buffered {@link Writer} for writing to this sink. The returned stream is not

    assertThat(e).hasMessageThat().contains(ERROR_PARALLEL_EDGE);
    e =
        assertThrows(
            IllegalArgumentException.class,
            () -> networkAsMutableNetwork.addEdge(N2, N1, EDGE_NOT_IN_GRAPH));
    assertThat(e).hasMessageThat().contains(ERROR_PARALLEL_EDGE);
  }

  @Test
  public void addEdge_parallelEdge_allowsParallelEdges() {

            IllegalArgumentException.class, () -> networkAsMutableNetwork.addEdge(N4, N5, E12));
    assertThat(e).hasMessageThat().contains(ERROR_REUSE_EDGE);
    e = assertThrows(IllegalArgumentException.class, () -> addEdge(N2, N1, E12));
    assertThat(e).hasMessageThat().contains(ERROR_REUSE_EDGE);
  }

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

   * data, and vertical if there is variance in the {@code y} data but not the {@code x} data.
   *
   * <p>This fit minimizes the root-mean-square error in {@code y} as a function of {@code x}. This
   * error is defined as the square root of the mean of the squares of the differences between the
   * actual {@code y} values of the data and the values predicted by the fit for the {@code x}

        new Suppression(c1, tryException, c1Exception));
  }

  public void testErrors() throws IOException {
    Closer closer = new Closer(suppressor);

    Error c1Exception = new Error();
    Error c2Exception = new Error();
    Error c3Exception = new Error();

    TestCloseable c1 = closer.register(TestCloseable.throwsOnClose(c1Exception));
    TestCloseable c2 = closer.register(TestCloseable.throwsOnClose(c2Exception));

          } catch (Exception e) { // sneaky checked exception
            AssertionError error =
                new AssertionFailedError("Serialization failed on return value of " + factory);
            error.initCause(e.getCause());
            throw error;
          } catch (AssertionFailedError e) {
            AssertionError error =
                new AssertionFailedError(

   *
   * @param cbuf the character buffer to process
   * @param off the offset into the buffer
   * @param len the number of characters to process
   * @throws IOException if an I/O error occurs
   * @see #finish
   */
  protected void add(char[] cbuf, int off, int len) throws IOException {
    int pos = off;
    if (sawReturn && len > 0) {