assertNotNull(impl, "Implementation instance should not be null");
        assertTrue(SessionSetupHandler.class.isInstance(impl), "Instance should be assignable to interface");
        assertTrue(SessionSetupHandler.class.isAssignableFrom(impl.getClass()), "Type should be assignable");
    }

    @Test
    @DisplayName("Edge: null is not an instance of the interface")
    void testNullIsNotInstance() {
        // Assert

        SmbTreeImpl unwrapped = tree.unwrap(SmbTreeImpl.class);
        assertEquals(tree, unwrapped);
        // Test unwrapping to a non-assignable type should fail
        assertThrows(ClassCastException.class, () -> {
            // Create a mock class that extends SmbTree but is not assignable from SmbTreeImpl
            class CustomSmbTree extends SmbTreeImpl {
                CustomSmbTree() {

        when(config.getPid()).thenReturn(12345);
        when(config.getSendBufferSize()).thenReturn(65536);

        target = new SmbPipeHandleImpl(pipe);
    }

    @Test
    @DisplayName("unwrap returns self for assignable type; throws for incompatible and null")
    void testUnwrap() {
        // Happy path: unwrap to concrete type
        SmbPipeHandleImpl unwrapped = target.unwrap(SmbPipeHandleImpl.class);

        }
    }

    @Nested
    @DisplayName("IOException Compatibility Tests")
    class IOExceptionCompatibilityTests {

        @Test
        @DisplayName("Should be assignable to IOException")
        void testIsIOException() {
            TransportException exception = new TransportException("Test");

            assertTrue(exception instanceof IOException);

defined type while the latter is a type literal
(but they are still <a href="#Assignability">assignable</a>).
</p>

<h3 id="Assignability">Assignability</h3>

<p>
A value <code>x</code> of type <code>V</code> is <i>assignable</i> to a <a href="#Variables">variable</a> of type <code>T</code>
("<code>x</code> is assignable to <code>T</code>") if one of the following conditions applies:
</p>

<ul>
<li>

            assertEquals("DOM", sid.getDomainName());
            assertEquals("alice", sid.getAccountName());
        }

        @Test
        @DisplayName("unwrap returns this for assignable type; otherwise throws ClassCastException")
        void testUnwrap() throws Exception {
            SID sid = new SID("S-1-5-21-1");
            // Happy path
            assertSame(sid, sid.unwrap(SID.class));

      int k = 0;
      int i = takeIndex;
      while (k < count) {
        // This cast is not itself safe, but the following statement
        // will fail if the runtime type of items[i] is not assignable
        // to the runtime type of a[k++], which is all that the method
        // contract requires (see @throws ArrayStoreException above).
        @SuppressWarnings("unchecked")
        T t = (T) items[i];

    return new InstanceOfPredicate<>(clazz);
  }

  /**
   * Returns a predicate that evaluates to {@code true} if the class being tested is assignable to
   * (is a subtype of) {@code clazz}. Example:
   *
   * {@snippet :
   * List<Class<?>> classes = Arrays.asList(
   *     Object.class, String.class, Number.class, Long.class);

@GwtCompatible
@NullMarked
public abstract class MapInterfaceTest<K extends @Nullable Object, V extends @Nullable Object>
    extends TestCase {

  /** A key type that is not assignable to any classes but Object. */
  private static final class IncompatibleKeyType {
    @Override
    public String toString() {
      return "IncompatibleKeyType";
    }
  }

  protected final boolean supportsPut;

      return new Assignability<>();
    }
  }

  private static void assertAssignable(TypeToken<?> from, TypeToken<?> to) {
    assertTrue(
        from.getType() + " is expected to be assignable to " + to.getType(),
        to.isSupertypeOf(from));
    assertTrue(
        to.getType() + " is expected to be a supertype of " + from.getType(),
        to.isSupertypeOf(from));
    assertTrue(