CLI output is truncated

[Fred Emmott]

$ hhvm vendor/bin/hacktest tests/

......................................................................................................................................................EE.EEEEE......EE.EEEEE................................................S..............................................................................

1) Facebook\HHAST\MustUseOverrideAttributeLinterTest::testAutofix with data set #1 'overrides_grandparent'

Failed asserting that '<?hh // strict
/**
 * Copyright (c) 2016, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional
 * grant of patent rights can be found in the PATENTS file in the same
 * directory.
 *
 */

class Foo extends \\Facebook\\HHAST\\MustUseOverrideAttributeLinterTest {
  public function setUp(): void {
  }
}
' is the same as '<?hh // strict
/**
 * Copyright (c) 2016, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional
 * grant of patent rights can be found in the PATENTS file in the same
 * directory.
 *
 */

class Foo extends \\Facebook\\HHAST\\MustUseOverrideAttributeLinterTest {
  <<__fredemmott-pro:hhast fredemmott$

I'm guessing something (hh-clilib?) needs to check how many bytes were actually written - possibly trying to write more than $BUFFER_SIZE (it's suspiciously close to 1024)