bufferHelper("no newlines at all", "no newlines at all");
    bufferHelper("two lines\nbut no newline at end", "two lines\n", "but no newline at end");
    bufferHelper(
        "\nempty first line\nno newline at end", "\n", "empty first line\n", "no newline at end");
    bufferHelper("three\rlines\rno newline at end", "three\r", "lines\r", "no newline at end");
    bufferHelper("mixed\nline\rendings\r\n", "mixed\n", "line\r", "endings\r\n");

    }
    reader.close();
    writer.close();

    assertExpectedString(writer.toString());
  }

  public void testLines() throws IOException {
    try (Stream<String> lines = source.lines()) {
      assertExpectedLines(lines.collect(toImmutableList()));
    }
  }

  public void testCopyTo_appendable() throws IOException {
    StringBuilder builder = new StringBuilder();

    PlexusContainer container;

    @Test
    void testAptConsistency() throws Exception {
        File apt = getTestFile("src/site/apt/artifact-handlers.apt");

        List<String> lines = Files.readAllLines(apt.toPath());

        for (String line : lines) {
            if (line.startsWith("||")) {
                String[] cols = line.split("\\|\\|");
                String[] expected = new String[] {
                    "",

   */
  @CanIgnoreReturnValue // some uses know that their processor never returns false
  boolean processLine(String line) throws IOException;

  /** Return the result of processing all the lines. */
  @ParametricNullness
  T getResult();

                if (line.length() == 0 || line.charAt(0) == '#') {
                    if (updater != null) {
                        updater.write(line);
                    }
                    continue; // ignore empty lines and comments
                }

                String[] inputs;
                String[] outputs;

                final List<String> sides = split(line, "=>");

  }

  /**
   * Returns a splitter that considers any subsequence matching {@code pattern} to be a separator.
   * For example, {@code Splitter.on(Pattern.compile("\r?\n")).split(entireFile)} splits a string
   * into lines whether it uses DOS-style or UNIX-style line terminators.
   *
   * @param separatorPattern the pattern that determines whether a subsequence is a separator. This
   *     pattern may not match the empty string.

   * scattered in memory and thus don't interfere much with each
   * other. But Atomic objects residing in arrays will tend to be
   * placed adjacent to each other, and so will most often share
   * cache lines (with a huge negative performance impact) without
   * this precaution.
   *
   * In part because Cells are relatively large, we avoid creating
   * them until they are needed.  When there is no contention, all

   */
  public static final byte NL = 10;

  /**
   * Vertical Tabulation ('\v'): A format effector which controls the movement of the printing
   * position to the next in a series of predetermined printing lines. (Applicable also to display
   * devices.)
   *
   * @since 8.0
   */
  public static final byte VT = 11;

  /**

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    TestCharSource lines = new TestCharSource(LINES);
    assertEquals("foo", lines.readFirstLine());
    assertTrue(lines.wasStreamOpened() && lines.wasStreamClosed());
  }

  public void testReadLines_toList() throws IOException {
    TestCharSource lines = new TestCharSource(LINES);
    assertEquals(ImmutableList.of("foo", "bar", "baz", "something"), lines.readLines());