assertThrows(
        "expected IllegalArgumentException for call to slice with offset -1: " + source,
        IllegalArgumentException.class,
        () -> source.slice(-1, 0));

    assertThrows(
        "expected IllegalArgumentException for call to slice with length -1: " + source,
        IllegalArgumentException.class,
        () -> source.slice(0, -1));
  }

    assertThrows(
        "expected IllegalArgumentException for call to slice with offset -1: " + source,
        IllegalArgumentException.class,
        () -> source.slice(-1, 0));

    assertThrows(
        "expected IllegalArgumentException for call to slice with length -1: " + source,
        IllegalArgumentException.class,
        () -> source.slice(0, -1));
  }