Проблема при издевательстве AmazonECRClientBuilder

Question

Я пытаюсь написать тестовый пример для моего проекта, ниже приведен код

 public AmazonECR getClient() {
        return AmazonECRClientBuilder.standard()
                .withCredentials(new AWSStaticCredentialsProvider(new BasicAWSCredentials(key, secret)))
                .withRegion(region)
                .build();
    }

Ниже приведен мой тестовый пример

@Test
public void getEcrClientTest() {
    when(ecrBuilder.standard()
        .withCredentials(any())
        .withRegion("")
        .build()).thenReturn(ecrBuilder.defaultClient());
    AmazonECR resp = awsUtils.getEcrClient();
    assertTrue(resp instanceof AmazonECR);
}

Я получаю ошибку ниже

org.mockito.exceptions.base.MockitoException: 
Cannot mock/spy class com.amazonaws.services.s3.AmazonS3ClientBuilder
Mockito cannot mock/spy because :
 - final class

    at org.mockito.internal.runners.DefaultInternalRunner$1$1.evaluate(DefaultInternalRunner.java:43)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.mockito.internal.runners.DefaultInternalRunner$1.run(DefaultInternalRunner.java:74)
    at org.mockito.internal.runners.DefaultInternalRunner.run(DefaultInternalRunner.java:80)
    at org.mockito.internal.runners.StrictRunner.run(StrictRunner.java:39)
    at org.mockito.junit.MockitoJUnitRunner.run(MockitoJUnitRunner.java:163)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
    at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
    at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)
    at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)

Я новичок в Mokito и Junit, любая помощь приветствуется.