StringAnonymizer { public int getStringCount() { return mapping.size(); }  static String getAlpha(int num); int getStringCount(); String anonymize(String str); String deanonymize(String str); void readCsv(BufferedReader reader); void readCsv(BufferedReader reader, char separator); void writeCsv(BufferedWriter writer); void writeCsv(BufferedWriter writer, char separator);  }
@Test public void invalidFileTest() throws IOException { String csv = String.join(System.lineSeparator(), "", "A;B"); StringAnonymizer anonymizer = fromCsv(csv); assertEquals(1, anonymizer.getStringCount()); }