}

  public void testCopyOf_arrayOfOneElement() {
    String[] array = new String[] {"a"};
    Set<String> set = copyOf(array);
    assertEquals(singleton("a"), set);
  }

  public void testCopyOf_nullArray() {
    assertThrows(NullPointerException.class, () -> copyOf((String[]) null));
  }

  public void testCopyOf_arrayContainingOnlyNull() {
    @Nullable String[] array = new @Nullable String[] {null};

  public void testCopyOf_arrayOfOneElement() {
    String[] array = new String[] {"a"};
    List<String> list = ImmutableList.copyOf(array);
    assertEquals(singletonList("a"), list);
  }

  public void testCopyOf_nullArray() {
    assertThrows(NullPointerException.class, () -> ImmutableList.copyOf((String[]) null));
  }

  public void testCopyOf_arrayContainingOnlyNull() {

  public void testCopyOf_arrayOfOneElement() {
    String[] array = new String[] {"a"};
    List<String> list = ImmutableList.copyOf(array);
    assertEquals(singletonList("a"), list);
  }

  public void testCopyOf_nullArray() {
    assertThrows(NullPointerException.class, () -> ImmutableList.copyOf((String[]) null));
  }

  public void testCopyOf_arrayContainingOnlyNull() {