### Question:
StringTrimmerConverter implements Converter<String, String> { @Override public String convert(String source) { if (source == null) { return null; } String trimmedString = source.trim(); if (emptyAsNull && trimmedString.length() == 0) { return null; } else { return trimmedString; } } StringTrimmerConverter(boolean emptyAsNull); @Override String convert(String source);  }### Answer:
@Test public void testConvertValue() { final StringTrimmerConverter stringTrimmingConverter = new StringTrimmerConverter(emptyAsNull.booleanValue()); assertThat(stringTrimmingConverter.convert(input)).isEqualTo( expectedOutput); }