public Stats yStats() {
    return yStats.snapshot();
  }

  /**
   * Returns the population covariance of the values. The count must be non-zero.
   *
   * <p>This is guaranteed to return zero if the dataset contains a single pair of finite values. It
   * is not guaranteed to return zero when the dataset consists of the same pair of values multiple
   * times, due to numerical errors.
   *
   * <h3>Non-finite values</h3>
   *

  @CollectionSize.Require(absent = ZERO)
  public void testAddAllAtIndex_supportedAllPresent() {
    assertTrue(
        "addAll(n, allPresent) should return true",
        getList().addAll(0, MinimalCollection.of(e0())));
    expectAdded(0, e0());
  }

  @ListFeature.Require(absent = SUPPORTS_ADD_WITH_INDEX)
  @CollectionSize.Require(absent = ZERO)
  public void testAddAllAtIndex_unsupportedAllPresent() {

import static com.google.common.collect.testing.features.CollectionSize.ONE;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;
import org.junit.Ignore;

/**

 * limitations under the License.
 */

package com.google.common.collect.testing.testers;

import static com.google.common.collect.testing.features.CollectionSize.ZERO;
import static java.util.Arrays.asList;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.features.CollectionSize;
import org.junit.Ignore;

/**

        if (size.divide(ONE_EB_BI).compareTo(BigInteger.ZERO) > 0) {
            displaySize = new BigDecimal(size.divide(ONE_PB_BI)).divide(BigDecimal.valueOf(1000)) + "EB";
        } else if (size.divide(ONE_PB_BI).compareTo(BigInteger.ZERO) > 0) {
            displaySize = new BigDecimal(size.divide(ONE_TB_BI)).divide(BigDecimal.valueOf(1000)) + "PB";
        } else if (size.divide(ONE_TB_BI).compareTo(BigInteger.ZERO) > 0) {

  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testRemovePresent() {
    assertTrue(multimap().remove(k0(), v0()));

    assertFalse(multimap().containsEntry(k0(), v0()));
    expectMissing(e0());
    assertEquals(getNumElements() - 1, multimap().size());
    assertGet(k0(), ImmutableList.<V>of());
  }

  @CollectionSize.Require(absent = ZERO)

 * limitations under the License.
 */

package com.google.common.collect.testing.testers;

import static com.google.common.collect.testing.features.CollectionSize.ZERO;
import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEYS;
import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_VALUES;

 * limitations under the License.
 */

package com.google.common.collect.testing.testers;

import static com.google.common.collect.testing.features.CollectionSize.ZERO;
import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEYS;
import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_VALUES;

  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testRemovePresent() {
    assertTrue(multimap().remove(k0(), v0()));

    assertFalse(multimap().containsEntry(k0(), v0()));
    expectMissing(e0());
    assertEquals(getNumElements() - 1, multimap().size());
    assertGet(k0(), ImmutableList.<V>of());
  }

  @CollectionSize.Require(absent = ZERO)

  }

  @MapFeature.Require(ALLOWS_NULL_KEYS)
  @CollectionSize.Require(absent = ZERO)
  public void testContains_nonNullWhenNullContained() {
    initMapWithNullKey();
    assertFalse("containsKey(notPresent) should return false", getMap().containsKey(k3()));
  }

  @MapFeature.Require(ALLOWS_NULL_KEYS)
  @CollectionSize.Require(absent = ZERO)
  public void testContains_nullContained() {
    initMapWithNullKey();