### Question:
StringType implements ArgumentType<String> { public String toText(String value) { if (value == null) { return ""; } return ArgumentUtil.encode(value); }  String toObject(String value); String toText(String value);  }### Answer:
@Test public void testToText() { assertEquals("'aaa'", stringType.toText("aaa")); }
@Test public void testToText_empty() { assertEquals("''", stringType.toText("")); }