[英]How can I create unit test for void method with try…catch inside?
I create simple service for example: 我创建简单的服务,例如:
public class MyService {
public void process() {
try {
CustomerMessagesService customerMessagesService = new CustomerMessagesService();
String message = customerMessagesService.getMessage();
// another logic which can throw an exception
SpamCenterService spamCenterService = new SpamCenterService();
spamCenterService.sendAdvertise(message);
} catch (Exception e) {
e.printStackTrace();
}
}
}
This service calls from Scheduler each 1 second. 此服务每1秒从Scheduler调用一次。
customerMessagesService
return message with an advertisement text or throw an exception if this message contains illegal text. customerMessagesService
返回带有广告文本的消息,如果此消息包含非法文本,则引发异常。 If customerMessagesService
return success text - it to send to spamCenterService
and if customerMessagesService
throw an exception - it exception just logged. 如果
customerMessagesService
返回成功文本-发送给spamCenterService
,并且customerMessagesService
引发异常-则记录该异常。 There is another logic which can throw exception between calls of these services. 还有另一种逻辑可以在这些服务的调用之间引发异常。 This exception logs too.
该异常也会记录。
Now I want to create a unit test for this method. 现在,我想为此方法创建一个单元测试 。 But I don't understand how to test the
void
method with try..catch
block. 但是我不明白如何用
try..catch
块测试void
方法。
I create this: 我创建这个:
public class MyServiceTest {
private MyService myService;
@Before
public void setUp() {
myService = new MyService();
}
@Test
public void process() {
myService.process();
}
}
But it is always a success because the process method doesn't throw exceptions. 但这总是成功的,因为处理方法不会引发异常。 How can I test this method?
如何测试此方法?
EDIT 编辑
I find one solution but I am not sure about it. 我找到了一种解决方案,但我不确定。
public class MyServiceImpl implements MyService { 公共类MyServiceImpl实现MyService {
public void process() {
try {
doIt();
} catch (Exception e) {
e.printStackTrace();
}
}
public void doIt() throws Exception {
CustomerMessagesService customerMessagesService = new CustomerMessagesService();
String message = customerMessagesService.getMessage();
// another logic which can throw an exception
SpamCenterService spamCenterService = new SpamCenterService();
spamCenterService.sendAdvertise(message);
}
}
And test doIt()
method in MyServiceImpl
. 然后在
MyServiceImpl
测试doIt()
方法。
In short do the following: 简而言之,请执行以下操作:
A concrete example below: 下面是一个具体示例:
public class MyService {
private CustomerMessagesService customerMessagesService;
private SpamCenterService spamCenterService;
//inject dependencies
public MyService(CustomerMessagesService customerMessagesService, SpamCenterService spamCenterService) {
this.customerMessagesService = customerMessagesService;
this.spamCenterService = spamCenterService;
}
public void process() {
try {
String message = customerMessagesService.getMessage();
// another logic which can throw an exception
spamCenterService.sendAdvertise(message);
} catch (Exception e) {
e.printStackTrace();
}
}
}
public class MyServiceTest {
private MyService myService;
// mock dependencies with Mockito
private CustomerMessagesService customerMessagesService = Mockito.mock(CustomerMessagesService.class);
private SpamCenterService spamCenterService = Mockito.mock(SpamCenterService.class);
@Before
public void setUp() {
myService = new MyService(customerMessagesService, spamCenterService);
}
@Test
public void process() {
myService.process();
Mockito.verify(customerMessagesService).getMessage();
ArgumentCaptor<String> messageCaptor = ArgumentCaptor.forClass(String.class);
Mockito.verify(spamCenterService).sendAdvertise(messageCaptor.capture());
assertThat(messageCaptor.getValue(), is(nullValue()));
}
@Test
public void processWithSpecificCustomerMessageServiceBehaviour() {
Mockito.given(customerMessagesService.getMessage()).willReturn("expectedString");
myService.process();
ArgumentCaptor<String> messageCaptor = ArgumentCaptor.forClass(String.class);
Mockito.verify(spamCenterService).sendAdvertise(messageCaptor.capture());
assertThat(messageCaptor.getValue(), is("expectedString"));
}
@Test
public void processCatchExceptions() {
Mockito.given(customerMessagesService.getMessage()).willThrow(new Exception("Bad message"));
myService.process();
// if exception is thrown then the code should not reach spamCenterService.sendAdvertise()
Mockito.verify(spamCenterService, Mockito.never()).sendAdvertise(Mockito.anyString());
}
}
Note that you can also setup mocks to throw specific exceptions or return specific values so that you can test all possible scenarios. 请注意,您还可以设置模拟以引发特定的异常或返回特定的值,以便可以测试所有可能的方案。
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