Optional<Long> sizeIfKnown = source.sizeIfKnown();
    if (sizeIfKnown.isPresent()) {
      assertEquals(expected.length, (long) sizeIfKnown.get());
    }
  }

  public void testContentEquals() throws IOException {
    assertTrue(
        source.contentEquals(
            new ByteSource() {
              @Override
              public InputStream openStream() throws IOException {

    // Pasted this expected string from `echo hamburger | md5sum`
    assertEquals("cfa0c5002275c90508338a5cdb2a9781", byteSource.hash(Hashing.md5()).toString());
  }

  public void testContentEquals() throws IOException {
    assertTrue(source.contentEquals(source));
    assertTrue(source.wasStreamOpened() && source.wasStreamClosed());

    ByteSource equalSource = new TestByteSource(bytes);

    // Pasted this expected string from `echo hamburger | md5sum`
    assertEquals("cfa0c5002275c90508338a5cdb2a9781", byteSource.hash(Hashing.md5()).toString());
  }

  public void testContentEquals() throws IOException {
    assertTrue(source.contentEquals(source));
    assertTrue(source.wasStreamOpened() && source.wasStreamClosed());

    ByteSource equalSource = new TestByteSource(bytes);