### Question:
Groups { public List<String> getGroupNames() { if (this.groups == null) { return new ArrayList<>(); } return this.groups.stream().map(GroupInfo::getName).collect(Collectors.toList()); }  List<String> getGroupNames(); Boolean any(String... groupNames); GroupInfo getGroup(String groupName);  }### Answer:
@Test public void should_getGroupNames_when_groupsExist() { Groups sut = this.generateSut(); List<String> result = sut.getGroupNames(); assertEquals(3, result.size()); assertEquals("group.1", result.get(0)); assertEquals("group.2", result.get(1)); assertEquals("group.3", result.get(2)); }