CsvSaver { public String saveToString(DataFrame df) { StringWriter out = new StringWriter(); save(df, out); return out.toString(); } CsvSaver(); CsvSaver format(CSVFormat format); CsvSaver createMissingDirs(); CsvSaver noHeader(); void save(DataFrame df, File file); void save(DataFrame df, String fileName); void save(DataFrame df, Appendable out); String saveToString(DataFrame df);  }
@Test public void testSaveToString() { DataFrame df = DataFrame.newFrame("A", "B").foldByRow( 1, 2, 3, 4); assertEquals("A,B\r\n" + "1,2\r\n" + "3,4\r\n", Csv.saver().saveToString(df)); }