return list;
              }
            });
    assertEquals(ImmutableList.of("foo"), list);
    assertTrue(lines.wasStreamOpened() && lines.wasStreamClosed());
  }

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

    ImmutableList.Builder<String> builder = ImmutableList.builder();
    source.forEachLine(builder::add);