LoginContext lc = new LoginContext(loginContextName);
        lc.login();
        this.subject = lc.getSubject();
    }


    public KerberosKey[] getKeys () {
        List<Key> serverKeys = new ArrayList<>();

        Set<Object> serverPrivateCredentials = this.subject.getPrivateCredentials();
        for ( Object credential : serverPrivateCredentials )
            if ( credential instanceof KerberosKey )

     */
    final class Key<T> {

        private final Class<T> type;
        private final Object id;

        private Key(Class<T> type, Object id) {
            this.type = type;
            this.id = id;
        }

        public Class<T> type() {
            return type;
        }

        @Override
        public boolean equals(Object o) {

    } catch (UnsupportedOperationException expected) {
    }
    expectUnchanged();
    assertTrue(collection.contains(e0()));
  }

  /*
   * AbstractCollection fails the removeAll(null) test when the subject
   * collection is empty, but we'd still like to test removeAll(null) when we
   * can. We split the test into empty and non-empty cases. This allows us to
   * suppress only the former.
   */

            ImmutableList.asImmutableList(elements, n), comparator);
      }
    }
  }

  int unsafeCompare(Object a, @CheckForNull Object b) {
    return unsafeCompare(comparator, a, b);
  }

  static int unsafeCompare(Comparator<?> comparator, Object a, @CheckForNull Object b) {
    // Pretend the comparator can compare anything. If it turns out it can't

   * @return the contents of the container under test, for use by {@link #expectContents(Object[])
   *     expectContents(E...)} and its friends.
   */
  protected abstract Collection<E> actualContents();

  /**
   * Replaces the existing container under test with a new container created by the subject
   * generator.
   *
   * @see #resetContainer(Object) resetContainer(C)
   * @return the new container instance.
   */

    initCollectionWithNullElement();
    expectReturnsTrue(disjoint);
    expectContents();
  }

  // retainAll(null)

  /*
   * AbstractCollection fails the retainAll(null) test when the subject
   * collection is empty, but we'd still like to test retainAll(null) when we
   * can. We split the test into empty and non-empty cases. This allows us to
   * suppress only the former.
   */

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.features.CollectionSize;
import java.util.Collection;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * The subject-generator interface accepted by Collection testers, for testing a Collection at one
 * particular {@link CollectionSize}.
 *
 * <p>This interface should not be implemented outside this package; {@link

    String MAIL_SMTP_SERVER_MAIN_HOST_AND_PORT = "mail.smtp.server.main.host.and.port";

    /** The key of the configuration. e.g. [Test] */
    String MAIL_SUBJECT_TEST_PREFIX = "mail.subject.test.prefix";

    /** The key of the configuration. e.g. root@localhost */
    String MAIL_RETURN_PATH = "mail.return.path";

    /**
     * Get the value of property as {@link String}.

  public void testReuseBuilderReducingHashTableSizeWithPowerOfTwoTotalElements() {
    ImmutableSet.Builder<Object> builder = ImmutableSet.builderWithExpectedSize(6);
    builder.add(0);
    ImmutableSet<Object> unused = builder.build();
    ImmutableSet<Object> subject = builder.add(1).add(2).add(3).build();
    assertFalse(subject.contains(4));
  }

            }

            @Override
            protected OptionalThing<SMailSubjectFilter> createSubjectFilter() {
                return OptionalThing.of((view, subject) -> subject);
            }

            @Override
            protected OptionalThing<SMailAsyncStrategy> createAsyncStrategy() {
                return OptionalThing.of((view, runnable) -> async(asyncManager, runnable));