writer.write(buf, 0, read);
    }
    reader.close();
    writer.close();

    assertTrue(source.wasStreamClosed());
    assertEquals(STRING, writer.toString());
  }

  public void testLines() throws IOException {
    source = new TestCharSource(LINES);

    ImmutableList<String> lines;
    try (Stream<String> linesStream = source.lines()) {
      assertTrue(source.wasStreamOpened());

        UnsignedLong unsignedSum = aUnsigned.plus(bUnsigned);
        assertThat(unsignedSum.longValue()).isEqualTo(expected);
      }
    }
  }

  public void testMinus() {
    for (long a : TEST_LONGS) {
      for (long b : TEST_LONGS) {
        UnsignedLong aUnsigned = UnsignedLong.fromLongBits(a);
        UnsignedLong bUnsigned = UnsignedLong.fromLongBits(b);
        long expected =

        UnsignedLong unsignedSum = aUnsigned.plus(bUnsigned);
        assertThat(unsignedSum.longValue()).isEqualTo(expected);
      }
    }
  }

  public void testMinus() {
    for (long a : TEST_LONGS) {
      for (long b : TEST_LONGS) {
        UnsignedLong aUnsigned = UnsignedLong.fromLongBits(a);
        UnsignedLong bUnsigned = UnsignedLong.fromLongBits(b);
        long expected =