### Question:
PasswordGenerator { public String generate() { StringBuilder sb = new StringBuilder(); sb.append(lower.fragment()); sb.append(upper.fragment()); sb.append(numbers.fragment()); sb.append(symbols.fragment()); return shuffleAndJoin(sb.toString().toCharArray()); }  Config lower(); Config upper(); Config numbers(); Config symbols(); String generate();  }### Answer:
@Test public void defaultGeneratorContainsAll() { String password = new PasswordGenerator().generate(); assertTrue(password.matches(".*[a-z].*[a-z].*")); assertTrue(password.matches(".*[A-Z].*[A-Z].*")); assertTrue(password.matches(".*[0-9].*[0-9].*")); assertTrue(password.replaceAll("[a-zA-Z0-9]", "").length() > 0); }