code: @NotNull LineDiff[] compareContents(@NotNull File actual, @NotNull File expected) throws IOException {
      InputStream ais = null;
      InputStream eis = null;
      try {
        ais = new FileInputStream(actual);
        eis = new FileInputStream(expected);
        List<LineDiff> diffs = verifyEqualContent(readerFor(ais), readerFor(eis));
        return diffs.toArray(new LineDiff[diffs.size()]);
      } finally {
        closeQuietly(eis);
        closeQuietly(ais);
      }
    }
docs: /*
  Verifies that the given files have the same content. Adapted from <a
  href="http://junit-addons.sourceforge.net/junitx/framework/FileAssert.html" target="_blank">FileAssert</a> (from <a
  href="http://sourceforge.net/projects/junit-addons">JUnit-addons</a>.)