Mockito and ReloadableResourceBundleMessageSource doesn't go well together?

Question

I have this simple test, it isn't even a test as I'm simply trying to mock the messagesource.

I'm getting this error:

org.springframework.context.NoSuchMessageException: No message 
found under code '' for locale 'null'.

Can anyone else verify this behavior?

This is a minimum spring boot skeleton test I set up because ReloadableResourceBundleMessageSource didn't work in another project, so I thought I'll just try it in the smallest unit possible.

@RunWith(MockitoJUnitRunner.class)
public class DemoApplicationTests {

    @Test
    public void contextLoads() {

    ReloadableResourceBundleMessageSource messageSource = 
    mock(ReloadableResourceBundleMessageSource.class);
    when(
       messageSource.getMessage(
           anyString(), 
           any(Object[].class), 
           any(Locale.class)
         )
       ).thenReturn("returnValue");

    System.out.println("test");

    } 
}

This is the error I get:

org.springframework.context.NoSuchMessageException: No message 
found under code '' for locale 'null'.

at org.springframework.context.support.AbstractMessageSource.getMessage(
AbstractMessageSource.java:159)
at com.example.DemoApplicationTests.contextLoads(
DemoApplicationTests.java:24)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at ....
....
....
....
com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(
JUnit4IdeaTestRunner.java:117)
at com.intellij.rt.execution.junit.JUnitStarter.
prepareStreamsAndStart(
JUnitStarter.java:234)
at com.intellij.rt.execution.junit.JUnitStarter.main(
JUnitStarter.java:74)

It seems to me that it's not able to mock it properly. I've also tried to mock the MessageSource interface to no avail.

I don't know what your question is, but the reason why it's not possible to stub `getMessage` is because it's declared `final` in `AbstractMessageSource`, which is the superclass of `ReloadableResourceBundleMessageSource`. Mockito can't stub final methods. — Dawood ibn Kareem, Dec 02 '15 at 07:57

score 4 · Accepted Answer · answered Dec 02 '15 at 11:02

4

As David Wallace said:

Mockito can't stub "final" methods, and as 'getMessage' is declared final you can't mock it.

answered Dec 02 '15 at 11:02

OddBeck

835
8
19

Your answer is basically a rip-off of @DavidWallace comment. You could have extended your answer by mentioning PowerMock which is able to [mock final methods](https://code.google.com/p/powermock/wiki/MockFinal) – Roman Vottner Dec 02 '15 at 11:19
3

The fact that it's a copy of my comment doesn't make it wrong. OddBeck did the right thing by posting this, whereas I was too lazy. He/she even attributed it properly. This does not deserve a downvote. – Dawood ibn Kareem Dec 02 '15 at 17:36
Thanks David W! @RomanVottner: I wasn't aware of PowerMock, and if I would have been aware of the issue with Mockito & final methods I would probably not have asked this question at all. – OddBeck Dec 03 '15 at 09:48

score 3 · Answer 2 · answered Mar 28 '16 at 09:02

I didn't want to use PowerMock, and I solved the problem creating a real ReloadableResourceBundleMessageSource bean and injected it into the class I wanted to test

// create the real bean
ReloadableResourceBundleMessageSource messageSource = new ReloadableResourceBundleMessageSource();
messageSource.setDefaultEncoding("UTF-8");
messageSource.setCacheSeconds(-1);
messageSource.setBasenames("classpath:conf-test/messages"); // this folder is just for testing and it contains a messages_en.properties file

// inject the bean into the class I wanted to test
ReflectionTestUtils.setField(service, "messageSource", messageSource);

score 1 · Answer 3 · answered Mar 05 '18 at 13:35

I found a work-around the mockito limitations to mocking final methods in this case.

Instead of mocking, I set the class after constructing it like this:

ReloadableResourceBundleMessageSource bundleMessageSource = new ReloadableResourceBundleMessageSource();
bundleMessageSource.setUseCodeAsDefaultMessage(true);

According to the official documentation:

Return whether to use the message code as default message instead of throwing a NoSuchMessageException. Useful for development and debugging. Default is "false".

Anyway we can get the message since above only return the message code? — Drake, Dec 08 '20 at 05:49

score 0 · Answer 4 · answered Sep 17 '19 at 06:35

Final methods can't mock. So I write a solution like this.

    ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
    messageSource.setUseCodeAsDefaultMessage(true);
    ReflectionTestUtils.setField(service, "messageSource", messageSource);

score 0 · Answer 5 · answered Aug 31 '22 at 10:07

I have successfully mocked ResourceBundleMessageSource combining Mockito and PowerMockito (according to this thread).

Here's an extract of my Unit Test :

@RunWith(PowerMockRunner.class)
@PrepareForTest({..., ResourceBundleMessageSource.class})
public class ClassUnderTest {
   @Mock
   ResourceBundleMessageSource resourceBundleMessageSourceMock;


   @Test
   public void myTest() {
      // Given
      ...;

      // When
      PowerMockito.mockStatic(ResourceBundleMessageSource.class);
      
      Mockito.when(resourceBundleMessageSourceMock.getMessage(ArgumentMatchers.anyString(), ArgumentMatchers.any(Object[].class),
        ArgumentMatchers.any(Locale.class)).thenReturn("aString");

      // Then
      ...;
   }

}

score 0 · Answer 6 · answered Jul 18 '23 at 16:49

Might be a ClassLoader problem, the Tests run differently.

In my case I had multiple maven modules, app and bl. So the Test run in bl and the message.properties was in app/src/main/resource.

Test your actual Classpath of the Test with:

[...]
ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource();
System.out.println(new File(getClass().getClassLoader().getResource(".").getFile()));
[...]

This gave me something like "C:/ws/myapp/bl/target/test-classes"

Solution in the Test was to set the ClassLoader of the actual test class and copy the resource file to the test resource folder of the bl module.

  messageSource.setBundleClassLoader(getClass().getClassLoader());
  messageSource.setBasename("messages");

Mockito and ReloadableResourceBundleMessageSource doesn't go well together?

6 Answers6