public void testCopyOf_nullArray() {
    try {
      copyOf((String[]) null);
      fail();
    } catch (NullPointerException expected) {
    }
  }

  public void testCopyOf_arrayContainingOnlyNull() {
    @Nullable String[] array = new @Nullable String[] {null};
    try {
      copyOf((String[]) array);
      fail();
    } catch (NullPointerException expected) {
    }
  }

  public void testCopyOf_nullArray() {
    try {
      copyOf((String[]) null);
      fail();
    } catch (NullPointerException expected) {
    }
  }

  public void testCopyOf_arrayContainingOnlyNull() {
    @Nullable String[] array = new @Nullable String[] {null};
    try {
      copyOf((String[]) array);
      fail();
    } catch (NullPointerException expected) {
    }
  }