我正在尝试测试一个数据库为空/数据库没有返回任何内容的场景。
我用 mockito 写了一个 junit4 测试类。 mockito 创建了一个服务类和 dao 类。起初,我定义了“when”方法并且它起作用了。后来,我尝试拉出“when”方法调用,看看会发生什么,无论如何它都起作用了。为什么?
当调用 myService.getDistinctObjectList() 时,类 myService 将调用 myDao 的所有四个方法。所以我想我必须模拟所有四种方法并返回虚拟结果。如果在未配置的情况下调用 myDao.someMethod() 会发生什么? MyDao 应该与数据库一起工作,但我没有给它任何东西。
附上MyDao和MyService的示例代码供引用。 (我简化了它们,MyDao 有四种方法,可以检索四种对象)
public class MyDaoImpl implements MyDao {
@SuppressWarnings("unused")
private DataSource dataSource;
private JdbcTemplate jdbcTemplate;
private String schema;
@ConstructorProperties({ "dataSource", "schema" })
private MyDaoImpl(DataSource dataSource, String schema) {
this.dataSource = dataSource;
this.schema = schema;
this.jdbcTemplate = new JdbcTemplate(dataSource);
}
@Override
public List<SomeObjectTypeA> listSomeObjectTypeA() {
return this.jdbcTemplate.query("select * from " + schema + ".SOME_TABLE", new RowMapper<SomeObjectTypeA>() {
@Override
public SoftBillAccount mapRow(ResultSet rs, int rowNum) throws SQLException {
String memberA = rs.getString("MEMBER_A");
String memberB = rs.getString("MEMBER_B");
}
});
}
public List<SomeObjectTypeA> listSomeObjectTypeB() {
//omitted
}
public List<SomeObjectTypeA> listSomeObjectTypeC() {
//omitted
}
public List<SomeObjectTypeA> listSomeObjectTypeD() {
//omitted
}
}
public class MyServiceImpl implements MyService {
private MyDao myDao;
public MyServiceImpl(){}
@ConstructorProperties({ "myDao" })
public MyServiceImpl(MyDao myDao) {
this.myDao = myDao;
}
@Override
public List<String> getSomeObjectTypeA_MemberA_Only() {
List<SomeObjectTypeA> list = myDao.listSomeObjectTypeA();
List<String> memberAList = new ArrayList<String>();
for (SomeObjectTypeA objectA : list) {
memberAList.add(objectA.getMemberA());
}
return memberAList;
}
}
public class MyServiceImpl implements MyService {
private MyDao myDao;
public MyServiceImpl(){}
@ConstructorProperties({ "myDao" })
public MyServiceImpl(MyDao myDao) {
this.myDao = myDao;
}
@Override
public List<String> getSomeObjectTypeA_MemberA_Only() {
List<SomeObjectTypeA> list = mydao.listSomeObjectTypeA();
List<String> memberAList = new ArrayList<String>();
for (SomeObjectTypeA objectA : list) {
memberAList.add(objectA.getMemberA());
}
return memberAList;
}
}
这是测试类:
public class Test1{
@InjectMocks
private MyServiceImpl myService;
@Mock
private MyDao myDao;
@Before
public void init() {
MockitoAnnotations.initMocks(this);
}
@Test
public void testEmptyDatabase() {
//ArrayList<SomeObjectTypeA> list = new ArrayList<SomeObjectTypeA>();
//list.add( new SomeObjectTypeA("A","A", "A", "A") );
//when(myDao.listSomeObjectTypeA()).thenReturn( Collections.<SomeObjectTypeA>emptyList() );
//when(myDao.listSomeObjectTypeB()).thenReturn( Collections.<SomeObjectTypeB>emptyList() );
//when(myDao.listSomeObjectTypeC()).thenReturn( Collections.<SomeObjectTypeC>emptyList() );
//when(myDao.listSomeObjectTypeD()).thenReturn( Collections.<SomeObjectTypeD>emptyList() );
List<String> distinctList = myService.getDistinctObjectList(); // myService.getDistinctObjectList() end up calling all four methods of myDao
//Write the List to a file, with a trailer with record count
OutputWriter outputWriter = new OutputWriterImpl(outputFileDir, outputFilePrefix,outputFileSuffix);
try{
outputWriter.writeOutput(distinctList);
}catch(IOException e){
e.printStackTrace();
}
//Create a control file for comparison
try{
BufferedWriter bfr = new BufferedWriter(new FileWriter(compareFileDir+compareFilePrefix+compareFileSuffix));
bfr.write("Trailer|");
bfr.write(String.format("%07d", 0));
bfr.newLine();
bfr.close();
}catch(IOException e){
e.printStackTrace();
}
File file1 = new File(outputFileDir + outputFilePrefix + date + outputFileSuffix);
File file2 = new File(compareFileDir+ compareFilePrefix+compareFileSuffix);
System.out.println(file1.length()); // show 17
System.out.println(file2.length()); // show 17
assertEquals(file1.length(), file2.length());
}
最佳答案
除非您显式更改模拟的默认行为,否则它将返回 "nice values" .对于集合,默认返回值为空集合,因此您无需像注释掉的代码那样显式使用 when
调用来返回此类空集合。
关于java - 为什么在不定义 "when"方法的情况下使用 Mockito 进行 JUnit 测试?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/51320563/