* 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}

        }

        List<String> errors = new ArrayList<>();
        pluginValidator.validate(pluginArtifact, pluginDescriptor, errors);

        if (!errors.isEmpty()) {
            throw new InvalidPluginDescriptorException(
                    "Invalid plugin descriptor for " + plugin.getId() + " (" + pluginFile + ")", errors);
        }

        pluginDescriptor.setPluginArtifact(pluginArtifact);

        }

        // reactor failure modes
        if (t instanceof RuntimeException || !(t instanceof Exception)) {
            // fail fast on RuntimeExceptions, Errors and "other" Throwables
            // assume these are system errors and further build is meaningless
            buildContext.getReactorBuildStatus().halt();

     * handleException() at all.
     */
    if (throwable instanceof Error) {
      /*
       * TODO(cpovirk): Do we really want to log this if we called setException(throwable) and it
       * returned true? This was intentional (CL 46470009), but it seems odd compared to how we
       * normally handle Error.
       *

    assertThat(verticalValuesAccumulatorByAddAllPartitionedPairedStats.sampleCovariance())
        .isWithin(ALLOWED_ERROR)
        .of(0.0);
    assertThat(constantValuesAccumulator.sampleCovariance()).isWithin(ALLOWED_ERROR).of(0.0);
    assertThat(constantValuesAccumulatorByAddAllPartitionedPairedStats.sampleCovariance())
        .isWithin(ALLOWED_ERROR)
        .of(0.0);
  }

    assertThat(verticalValuesAccumulatorByAddAllPartitionedPairedStats.sampleCovariance())
        .isWithin(ALLOWED_ERROR)
        .of(0.0);
    assertThat(constantValuesAccumulator.sampleCovariance()).isWithin(ALLOWED_ERROR).of(0.0);
    assertThat(constantValuesAccumulatorByAddAllPartitionedPairedStats.sampleCovariance())
        .isWithin(ALLOWED_ERROR)
        .of(0.0);
  }

    assertEquals(RUNTIME_EXCEPTION, expected);
  }

  public void testGetCheckedUntimed_Error() throws TwoArgConstructorException {
    try {
      getChecked(ERROR_FUTURE, TwoArgConstructorException.class);
    } catch (Error expected) {
      assertEquals(ERROR, expected);
      return;
    }
    fail();
  }

        log.warn(message.toString());
    }

    /**
     * ERROR情報を出力します。
     *
     * @param message
     *            メッセージ
     * @param throwable
     *            例外
     */
    public void error(final Object message, final Throwable throwable) {
        log.error(message.toString(), throwable);
    }

    /**
     * ERROR情報を出力します。
     *
     * @param message
     *            メッセージ

  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.";

            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();