public void testSampleCovariance() {
    assertThrows(IllegalStateException.class, () -> emptyAccumulator.sampleCovariance());
    assertThrows(
        IllegalStateException.class,
        () -> emptyAccumulatorByAddAllEmptyPairedStats.sampleCovariance());
    assertThrows(IllegalStateException.class, () -> oneValueAccumulator.sampleCovariance());
    assertThrows(
        IllegalStateException.class,

        // Close the authenticator
        auth.close();

        // All these operations should throw IllegalStateException
        assertThrows(IllegalStateException.class, () -> auth.getPassword());
        assertThrows(IllegalStateException.class, () -> auth.getPasswordAsCharArray());
        assertThrows(IllegalStateException.class, () -> {
            // This would normally be called during authentication

    assertThrows(IllegalStateException.class, () -> builder.maximumWeight(16));
    assertThrows(IllegalStateException.class, () -> builder.maximumSize(16));
  }

  @GwtIncompatible // maximumWeight
  public void testMaximumWeight_withoutWeigher() {
    CacheBuilder<Object, Object> builder = CacheBuilder.newBuilder().maximumWeight(1);
    assertThrows(IllegalStateException.class, () -> builder.build(identityLoader()));

   *
   * @throws IllegalStateException if the service reaches a state from which it is not possible to
   *     enter the {@link State#RUNNING} state. e.g. if the {@code state} is {@code
   *     State#TERMINATED} when this method is called then this will throw an IllegalStateException.
   * @since 15.0
   */
  void awaitRunning();

  /**

  public void testSampleCovariance() {
    assertThrows(IllegalStateException.class, () -> emptyAccumulator.sampleCovariance());
    assertThrows(
        IllegalStateException.class,
        () -> emptyAccumulatorByAddAllEmptyPairedStats.sampleCovariance());
    assertThrows(IllegalStateException.class, () -> oneValueAccumulator.sampleCovariance());
    assertThrows(
        IllegalStateException.class,

  public void testSampleVariance() {
    assertThrows(IllegalStateException.class, () -> emptyAccumulator.sampleVariance());
    assertThrows(
        IllegalStateException.class, () -> emptyAccumulatorByAddAllEmptyIterable.sampleVariance());
    assertThrows(
        IllegalStateException.class, () -> emptyAccumulatorByAddAllEmptyStats.sampleVariance());
    assertThrows(IllegalStateException.class, () -> oneValueAccumulator.sampleVariance());

  }

  public void testPearsonsCorrelationCoefficient() {
    assertThrows(
        IllegalStateException.class, () -> EMPTY_PAIRED_STATS.pearsonsCorrelationCoefficient());
    assertThrows(
        IllegalStateException.class, () -> ONE_VALUE_PAIRED_STATS.pearsonsCorrelationCoefficient());
    assertThrows(
        IllegalStateException.class,
        () -> createSingleStats(Double.POSITIVE_INFINITY, 1.23).pearsonsCorrelationCoefficient());

  }

  public void testPearsonsCorrelationCoefficient() {
    assertThrows(
        IllegalStateException.class, () -> EMPTY_PAIRED_STATS.pearsonsCorrelationCoefficient());
    assertThrows(
        IllegalStateException.class, () -> ONE_VALUE_PAIRED_STATS.pearsonsCorrelationCoefficient());
    assertThrows(
        IllegalStateException.class,
        () -> createSingleStats(Double.POSITIVE_INFINITY, 1.23).pearsonsCorrelationCoefficient());

      }
    }
    return suite;
  }

  /** Throw {@link IllegalStateException} if {@link #createTestSuite()} can't be called yet. */
  protected void checkCanCreate() {
    if (subjectGenerator == null) {
      throw new IllegalStateException("Call using() before createTestSuite().");
    }
    if (name == null) {
      throw new IllegalStateException("Call named() before createTestSuite().");
    }

        // Handle this specially so that we can include the failureCause, if there is one.
        throw new IllegalStateException(
            "Expected the service " + this + " to be " + expected + ", but the service has FAILED",
            failureCause());
      }
      throw new IllegalStateException(
          "Expected the service " + this + " to be " + expected + ", but was " + actual);
    }
  }

  /**