### Question:
FieldDescriptors { public FieldDescriptors andWithPrefix(String pathPrefix, FieldDescriptor... additionalDescriptors) { List<FieldDescriptor> combinedDescriptors = new ArrayList<>(fieldDescriptors); combinedDescriptors.addAll(applyPathPrefix(pathPrefix, Arrays.asList(additionalDescriptors))); return new FieldDescriptors(combinedDescriptors); } FieldDescriptors(FieldDescriptor... fieldDescriptors); FieldDescriptors and(FieldDescriptor... additionalDescriptors); FieldDescriptors andWithPrefix(String pathPrefix, FieldDescriptor... additionalDescriptors);  }### Answer:
@Test public void should_combine_descriptors_with_prefix() { fieldDescriptors = givenFieldDescriptors(); then(fieldDescriptors.andWithPrefix("d.", fieldWithPath("c")).getFieldDescriptors()) .extracting(FieldDescriptor::getPath).contains("a", "b", "d.c"); }