val relay = edit(file, upstream, metadata, 5)
    val source1 = relay.newSource()!!.buffer()
    val source2 = relay.newSource()!!.buffer()
    assertThat(source1.readUtf8(5)).isEqualTo("abcde")
    assertThat(source2.readUtf8(5)).isEqualTo("abcde")
    assertThat(source2.readUtf8(5)).isEqualTo("fghij")
    assertThat(source1.readUtf8(5)).isEqualTo("fghij")
    assertThat(source1.exhausted()).isTrue()

		{"DATA", "·D(SB)/5,$0.0", "bad float size for DATA argument: 5"},
		{"DATA", "·E(SB)/4,$·A(SB)", "bad addr size for DATA argument: 4"},
		{"DATA", "·F(SB)/8,$·A(SB)", ""},
		{"DATA", "·G(SB)/5,$\"abcde\"", ""},
		{"GLOBL", "", "expect two or three operands for GLOBL"},
		{"GLOBL", "0,1", "GLOBL symbol \"<erroneous symbol>\" must be a symbol(SB)"},
		{"GLOBL", "@B(SB), 0", "expected '(', found B"}, // Issue 23580.

    return new CharSource() {
      @Override
      public Reader openStream() {
        return new StringReader(text);
      }
    };
  }

  public void testSkip() throws Exception {
    String begin = "abcde";
    String end = "fghij";
    Reader joinedReader = CharSource.concat(newCharSource(begin), newCharSource(end)).openStream();

    String expected = begin + end;
    assertEquals(expected.charAt(0), joinedReader.read());

    return new CharSource() {
      @Override
      public Reader openStream() {
        return new StringReader(text);
      }
    };
  }

  public void testSkip() throws Exception {
    String begin = "abcde";
    String end = "fghij";
    Reader joinedReader = CharSource.concat(newCharSource(begin), newCharSource(end)).openStream();

    String expected = begin + end;
    assertEquals(expected.charAt(0), joinedReader.read());

  public void testReadEmptyString() throws IOException {
    assertReadsCorrectly("");
  }

  public void testReadsStringsCorrectly() throws IOException {
    assertReadsCorrectly("abc");
    assertReadsCorrectly("abcde");
    assertReadsCorrectly("abcdefghijkl");
    assertReadsCorrectly(
        ""
            + "abcdefghijklmnopqrstuvwxyz\n"
            + "ABCDEFGHIJKLMNOPQRSTUVWXYZ\r"
            + "0123456789\r\n"