Cannot use PowerMockRunner with SpringBootTest
<p>For my project, i am trying to write integration test using SpringBootTest. I have 3rd party static final class. I tried mock it with Power mock. But when try to using it @SpringBootTest, exception is thrown.</p>

<p>Here is my sample code</p>

<pre><code>@RunWith(PowerMockRunner.class)
@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT, classes =    SpringTestConfig.class
@PowerMockRunnerDelegate(SpringRunner.class)
@PrepareForTest(IdGenerator.class)
public class RestTestIT
{
   @Before
   public void setUp() throws Exception
   {
       PowerMockito.mockStatic(IdGenerator.class);
   }
 ..
}
</code></pre>

<p>Configuration:</p>

<pre><code>@Configuration
@EnableAutoConfiguration
@ComponentScan("com.xx.yy.zz")

public class SpringTestConfig
{
}
</code></pre>

<p>Exception thrown:</p>

<pre><code>2016-09-01 11:35:50.945 ERROR 18649 --- [           main] o.s.boot.SpringApplication               : Application startup failed

java.lang.IllegalArgumentException: Cannot find class [com.xx.yy.zz.SpringTestConfig$$EnhancerBySpringCGLIB$$414ee08e]
    at org.springframework.util.ClassUtils.resolveClassName(ClassUtils.java:287) ~[na:4.3.2.RELEASE]
    at org.springframework.boot.test.mock.mockito.MockitoPostProcessor.getConfigurationClasses(MockitoPostProcessor.java:147) ~[na:1.4.0.RELEASE]
    at org.springframework.boot.test.mock.mockito.MockitoPostProcessor.postProcessBeanFactory(MockitoPostProcessor.java:132) ~[na:1.4.0.RELEASE]
    at org.springframework.boot.test.mock.mockito.MockitoPostProcessor.postProcessBeanFactory(MockitoPostProcessor.java:126) ~[na:1.4.0.RELEASE]
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:284) ~[na:4.3.2.RELEASE]
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:174) ~[na:4.3.2.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:681) ~[na:4.3.2.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:523) ~[na:4.3.2.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[na:1.4.0.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) ~[na:1.4.0.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:369) ~[na:1.4.0.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:313) ~[na:1.4.0.RELEASE]
    at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:111) [na:1.4.0.RELEASE]
    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:98) [na:4.3.2.RELEASE]
    at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:116) [na:4.3.2.RELEASE]
    at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:83) [na:4.3.2.RELEASE]
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:117) [na:4.3.2.RELEASE]
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83) [na:4.3.2.RELEASE]
    at org.springframework.boot.test.autoconfigure.AutoConfigureReportTestExecutionListener.prepareTestInstance(AutoConfigureReportTestExecutionListener.java:46) [na:1.4.0.RELEASE]
    at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:230) [na:4.3.2.RELEASE]
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:228) [na:4.3.2.RELEASE]
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:287) [na:4.3.2.RELEASE]
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) [junit-4.12.jar:4.12]
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:289) [na:4.3.2.RELEASE]
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:247) [na:4.3.2.RELEASE]
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94) [na:4.3.2.RELEASE]
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) [junit-4.12.jar:4.12]
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) [na:4.3.2.RELEASE]
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70) [na:4.3.2.RELEASE]
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363) [junit-4.12.jar:4.12]
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191) [na:4.3.2.RELEASE]
    at org.powermock.modules.junit4.internal.impl.DelegatingPowerMockRunner$2.call(DelegatingPowerMockRunner.java:143) [na:na]
    at org.powermock.modules.junit4.internal.impl.DelegatingPowerMockRunner$2.call(DelegatingPowerMockRunner.java:136) [na:na]
    at org.powermock.modules.junit4.internal.impl.DelegatingPowerMockRunner.withContextClassLoader(DelegatingPowerMockRunner.java:127) [na:na]
    at org.powermock.modules.junit4.internal.impl.DelegatingPowerMockRunner.run(DelegatingPowerMockRunner.java:136) [na:na]
    at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.run(JUnit4TestSuiteChunkerImpl.java:106) [powermock-module-junit4-common-1.6.1.jar:na]
    at org.powermock.modules.junit4.common.internal.impl.AbstractCommonPowerMockRunner.run(AbstractCommonPowerMockRunner.java:53) [powermock-module-junit4-common-1.6.1.jar:na]
    at org.powermock.modules.junit4.PowerMockRunner.run(PowerMockRunner.java:59) [powermock-module-junit4-1.6.1.jar:na]
    at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:264) [surefire-junit4-2.16.jar:2.16]
    at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:153) [surefire-junit4-2.16.jar:2.16]
    at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:124) [surefire-junit4-2.16.jar:2.16]
    at org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:200) [surefire-booter-2.16.jar:2.16]
    at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:153) [surefire-booter-2.16.jar:2.16]
    at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:103) [surefire-booter-2.16.jar:2.16]
Caused by: java.lang.ClassNotFoundException: com.xx.yy.zz.SpringTestConfig$$EnhancerBySpringCGLIB$$414ee08e
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381) ~[na:1.8.0_92]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_92]
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) ~[na:1.8.0_92]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_92]
    at org.powermock.core.classloader.MockClassLoader.loadModifiedClass(MockClassLoader.java:178) ~[powermock-core-1.6.1.jar:na]
    at org.powermock.core.classloader.DeferSupportingClassLoader.loadClass(DeferSupportingClassLoader.java:68) ~[powermock-core-1.6.1.jar:na]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_92]
    at org.springframework.util.ClassUtils.forName(ClassUtils.java:250) ~[na:4.3.2.RELEASE]
    at org.springframework.util.ClassUtils.resolveClassName(ClassUtils.java:284) ~[na:4.3.2.RELEASE]
    ... 47 common frames omitted
</code></pre>

<p>Spring Boot Version: 1.4.0.RELEASE</p>

<pre><code>         &lt;dependency&gt;
             &lt;groupId&gt;org.powermock&lt;/groupId&gt;
             &lt;artifactId&gt;powermock-module-junit4&lt;/artifactId&gt;
             &lt;version&gt;1.6.1&lt;/version&gt;
             &lt;scope&gt;test&lt;/scope&gt;
         &lt;/dependency&gt;
         &lt;dependency&gt;
             &lt;groupId&gt;org.powermock&lt;/groupId&gt;
             &lt;artifactId&gt;powermock-api-mockito&lt;/artifactId&gt;
             &lt;version&gt;1.6.1&lt;/version&gt;
             &lt;scope&gt;test&lt;/scope&gt;
         &lt;/dependency&gt;
</code></pre>

<p>What i missing here? is it bug with springBoot?</p>

<p><strong>WORKAROUND:</strong>
I found a workaround for this to use SpringApplicationConfiguration, but this class is deprecated in SpringBootTest. So Not comfortable to use.  </p>

<pre><code>@RunWith(PowerMockRunner.class)
@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
@SpringApplicationConfiguration(classes = SpringTestConfig.class)
@PowerMockRunnerDelegate(SpringRunner.class)
@PrepareForTest(IdGenerator.class)

public class RestTestIT
{
</code></pre>