assertThat(Primitives.wrap(Integer.class)).isSameInstanceAs(Integer.class);
    assertThat(Primitives.wrap(String.class)).isSameInstanceAs(String.class);
  }

  public void testUnwrap() {
    assertThat(Primitives.unwrap(Integer.class)).isSameInstanceAs(int.class);
    assertThat(Primitives.unwrap(int.class)).isSameInstanceAs(int.class);

    assertThat(Primitives.wrap(Integer.class)).isSameInstanceAs(Integer.class);
    assertThat(Primitives.wrap(String.class)).isSameInstanceAs(String.class);
  }

  public void testUnwrap() {
    assertThat(Primitives.unwrap(Integer.class)).isSameInstanceAs(int.class);
    assertThat(Primitives.unwrap(int.class)).isSameInstanceAs(int.class);

	err := multiErr{multiErr{multiErr{errors.New("a"), errorT{"a"}}, errorT{"b"}}}
	for i := 0; i < b.N; i++ {
		var target errorT
		if !errors.As(err, &target) {
			b.Fatal("As failed")
		}
	}
}

func TestUnwrap(t *testing.T) {
	err1 := errors.New("1")
	erra := wrapped{"wrap 2", err1}

	testCases := []struct {
		err  error
		want error
	}{
		{nil, nil},
		{wrapped{"wrapped", nil}, nil},
		{err1, nil},