How to mock ResourceBundle.getString()?

Question

I'm failing to mock ResourceBundle.getString().

This is my code:

ResourceBundle schemaBundle = Mockito.mock(ResourceBundle.class);
Mockito.when(schemaBundle.getString("testKey_testPropertyName_ect")).thenReturn("testString1");

This gives the following exception on the second line:

java.util.MissingResourceException: Can't find resource for bundle $java.util.ResourceBundle$$EnhancerByMockitoWithCGLIB$$9e259f03, key testKey_testPropertyName_ect
    at java.util.ResourceBundle.getObject(ResourceBundle.java:374)
    at java.util.ResourceBundle.getString(ResourceBundle.java:334)
    at com.foo.bar.resource.PropertyResourceTest.testGet(PropertyResourceTest.java:104)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

To me this looks as if schemaBundle isn't mocked at all. But the debuger clearly shows, that the instance is wrapped by mockito.

I also tried with

Mockito.doReturn("testString1").when(schemaBundle).getString("testKey_testPropertyName_ect");

but this returns the same exception.

Any idea what's wrong?

See http://stackoverflow.com/questions/3793791/final-method-mocking — axtavt, Jul 30 '14 at 07:12
My bad, I missed that getString is final. Feel free to add your comment as an answer in order you get the credits. — BetaRide, Jul 30 '14 at 07:18
You may consider introducing one more bean - let's say `Messages`. It will have initialization block (locale setup, `getBundle` call) and `get(String key, String ... args)`. Next use through out your application calls to `Messages` instead of `ResourceBundle` coupling. And finally you may mock `Messages` in unit tests without any difficulties. — Aleksei Egorov, May 06 '16 at 10:46
I've found another option, https://stackoverflow.com/a/10816819/1060779 just adding the messages_xx_XX.properties in src/test/resources and it worked. — maxivis, May 29 '17 at 19:24
Another question being a kind of duplicate: https://stackoverflow.com/q/18377160/772981. Also contains an answer "no need to mock". — Jarekczek, Jul 24 '18 at 07:43

ccpizza · Accepted Answer · 2022-04-28T08:37:04.653

Instead of mocking you can create a dummy ResourceBundle implementation, and then pass it as an argument to .thenReturn(resourceBundle):

    import java.util.ResourceBundle;

    ResourceBundle dummyResourceBundle = new ResourceBundle() {
        @Override
        protected Object handleGetObject(String key) {
            return "fake_translated_value";
        }

        @Override
        public Enumeration<String> getKeys() {
            return Collections.emptyEnumeration();
        }
    };

    // Example usage
    when(request.getResourceBundle(any(Locale.class))).thenReturn(dummyResourceBundle)

If you need the actual keys and values, then you'll need to provide an implementation for getKeys(), e.g. a hashmap for storage and key lookup.

user2049200 · Answer 2 · 2014-10-22T21:25:21.217

You'll find an example of solution below :

@RunWith(PowerMockRunner.class)
@PrepareForTest({ ResourceBundle.class })
public class ResourceBundleTest {

    @Test
    public void getStringByPowerMock() throws Exception {   
        ResourceBundle resourceBundle = PowerMockito.mock(ResourceBundle.class);
        Mockito.when(resourceBundle.getString(Mockito.anyString())).thenReturn("Hello world....");
        System.out.println(resourceBundle.getString("keyword"));
    }

}

score 2 · Answer 3 · answered Jan 14 '18 at 10:19

@Powermockito did not worked as ResourceBundle.class have static final methods which were not easy to mock.

I tried.

In the Main Class extract your method inside another public method, and then overide it with implementaion.

Here ReviewEChannelApplicationMBean is my Controller, where i overrriden the getBundle.

ReviewEChannelApplicationMBean = spy(new ReviewEChannelApplicationMBean(){
            @Override
            public ResourceBundle getBundle(FacesContext fcContext) {
                return TestDataBuilder.getResourceBundle();
            }
        });

//This Class i my TestDataBuilder using ListResourceBundle

public class TestDataBuilder {
    public static ResourceBundle getResourceBundle() {
            return new ListResourceBundle(){

                @Override
                protected Object[][] getContents() {
                    return contents;
                }

                private Object[][] contents = {
                        {"test1","01"},
                        {"test2","01"},
                        {"test3","01"},
                        {"test4","01"}
                };
            };

        }
}

score 1 · Answer 4 · edited May 23 '17 at 12:33

1

I figured out a way to mock ResourceBundle by subclassing ResourceBundle.Control. My answer is here:

https://stackoverflow.com/a/28640458/290254

I prefer to avoid the dynamic bytecode rewriting (to remove final) of PowerMock, JMockit and friends, since Jacoco and other things seem to hate it.

edited May 23 '17 at 12:33

Community

1
1

answered Feb 26 '15 at 19:53

Julius Musseau

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score 0 · Answer 5 · answered Jul 21 '23 at 09:17

If You want mock such a situation:

ResourceBundle messages = ResourceBundle.getBundle("messages");
var msg = messages.getString("company.wizard.field.IsEnabledFromToReqDto.isNull");

U should use the next working variant:

@Test
void testMethodName() {
        //normally mock static
        try (MockedStatic<ResourceBundle> contextMock = mockStatic(ResourceBundle.class)) {
            //mock an object of mocked static
            ResourceBundle messages = mock(ResourceBundle.class);
            contextMock.when(() -> ResourceBundle.getBundle("messages")).thenReturn(messages);
            when(messages.getString(anyString())).thenReturn("Error message"); //or your own mock for messages

            //... your test...
            //... your verifying...
        }
    }

How to mock ResourceBundle.getString()?

5 Answers5

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