assertNotNull(result);
        assertEquals(16, result.length);
    }

    @Test
    void testHMACT64WithEmptyKey() {
        // Test with empty key
        byte[] emptyKey = new byte[0];
        HMACT64 hmac = new HMACT64(emptyKey);
        hmac.engineUpdate(TEST_DATA, 0, TEST_DATA.length);
        byte[] result = hmac.engineDigest();

        assertNotNull(result);
        assertEquals(16, result.length);

    @Test
    @DisplayName("Should accept empty keys")
    void testEmptyKeys() {
        // Given
        byte[] emptyKey = new byte[0];

        // When/Then
        assertDoesNotThrow(() -> {
            Smb2EncryptionContext context = new Smb2EncryptionContext(1, DialectVersion.SMB311, emptyKey, emptyKey);
            assertNotNull(context, "Context should be created with empty keys");
        }, "Should accept empty keys");

    Set<Object> set = new HashSet<>();
    assertThat(union(emptySet(), emptySet()).copyInto(set)).isSameInstanceAs(set);
    assertThat(intersection(emptySet(), emptySet()).copyInto(set)).isSameInstanceAs(set);
    assertThat(difference(emptySet(), emptySet()).copyInto(set)).isSameInstanceAs(set);
    assertThat(symmetricDifference(emptySet(), emptySet()).copyInto(set)).isSameInstanceAs(set);
  }

  }

  protected Collection<Method> suppressForCheckedMap() {
    return emptySet();
  }

  protected Collection<Method> suppressForCheckedSortedMap() {
    return emptySet();
  }

  protected Collection<Method> suppressForEmptyMap() {
    return emptySet();
  }

  protected Collection<Method> suppressForSingletonMap() {
    return emptySet();
  }

  protected Collection<Method> suppressForHashMap() {

  }

  protected Collection<Method> suppressForEmptyList() {
    return emptySet();
  }

  protected Collection<Method> suppressForSingletonList() {
    return emptySet();
  }

  protected Collection<Method> suppressForArraysAsList() {
    return emptySet();
  }

  protected Collection<Method> suppressForArrayList() {
    return emptySet();
  }

  protected Collection<Method> suppressForLinkedList() {

  }

  protected Collection<Method> suppressForEmptyList() {
    return emptySet();
  }

  protected Collection<Method> suppressForSingletonList() {
    return emptySet();
  }

  protected Collection<Method> suppressForArraysAsList() {
    return emptySet();
  }

  protected Collection<Method> suppressForArrayList() {
    return emptySet();
  }

  protected Collection<Method> suppressForLinkedList() {

    } catch (IllegalArgumentException e) {
      return emptySet(comparator());
    }
  }

  public ImmutableSortedSet<E> tailSet(E fromElement, boolean inclusive) {
    checkNotNull(fromElement);
    if (!inclusive) {
      E tmp = higher(fromElement);
      if (tmp == null) {
        return emptySet(comparator());
      }
      fromElement = tmp;
    }

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkPositionIndex;
import static java.util.Collections.emptyList;
import static java.util.Collections.emptySet;

import com.google.common.annotations.GwtCompatible;
import com.google.common.base.Predicate;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.j2objc.annotations.WeakOuter;

  }

  public TesterRequirements(TesterRequirements tr) {
    this(tr.getPresentFeatures(), tr.getAbsentFeatures());
  }

  public TesterRequirements() {
    this(Collections.emptySet(), Collections.emptySet());
  }

  public final Set<Feature<?>> getPresentFeatures() {
    return presentFeatures;
  }

  public final Set<Feature<?>> getAbsentFeatures() {
    return absentFeatures;
  }

  }

  public TesterRequirements(TesterRequirements tr) {
    this(tr.getPresentFeatures(), tr.getAbsentFeatures());
  }

  public TesterRequirements() {
    this(Collections.emptySet(), Collections.emptySet());
  }

  public final Set<Feature<?>> getPresentFeatures() {
    return presentFeatures;
  }

  public final Set<Feature<?>> getAbsentFeatures() {
    return absentFeatures;
  }