### Question:
ImportsValue { @Override public String toString() { final Collection<String> defaultImports = getDefaultImports().stream() .map(DefaultImport::toString) .collect(Collectors.toList()); final Collection<String> wsdlImports = getWSDLImports().stream() .map(WSDLImport::toString) .collect(Collectors.toList()); final String serializedValue = Stream.of(defaultImports, wsdlImports) .flatMap(Collection::stream) .collect(Collectors.joining(",")); return serializedValue; } ImportsValue();  ImportsValue(@MapsTo("defaultImports") final List<DefaultImport> defaultImports,
                        @MapsTo("wsdlImports") final List<WSDLImport> wsdlImports); List<DefaultImport> getDefaultImports(); void setDefaultImports(final List<DefaultImport> defaultImports); List<WSDLImport> getWSDLImports(); void setWSDLImports(final List<WSDLImport> wsdlImports); void addImport(final DefaultImport defaultImport); void addImport(final WSDLImport wsdlImport); @Override boolean equals(Object o); @Override int hashCode(); @Override String toString();  }### Answer:
@Test public void testToString() { ImportsValue tested1 = new ImportsValue(); assertEquals(STRING_EMPTY, tested1.toString()); ImportsValue tested2 = new ImportsValue(defaultImports, wsdlImports); String defaultImpString = buildImportsString(ImportType.DEFAULT, DEFAULT_IMPORTS_QTY); String wsdlImpString = buildImportsString(ImportType.WSDL, WSDL_IMPORTS_QTY); String expected = defaultImpString + "," + wsdlImpString; assertEquals(expected, tested2.toString()); }