Easymock with Powermock error - junit

Question

I am using Easymock with Powermock. When I try to test, this is the error I get.
java.lang.RuntimeException: Invoking the beforeTestMethod method on PowerMock test listener org.powermock.api.extension.listener.AnnotationEnabler#959a1da3 failed.
at org.powermock.tests.utils.impl.PowerMockTestNotifierImpl.notifyBeforeTestMethod(PowerMockTestNotifierImpl.java:95)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.executeTest(PowerMockJUnit44RunnerDelegateImpl.java:298)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTestInSuper(PowerMockJUnit47RunnerDelegateImpl.java:131)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.access$100(PowerMockJUnit47RunnerDelegateImpl.java:59)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner$TestExecutorStatement.evaluate(PowerMockJUnit47RunnerDelegateImpl.java:147)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.evaluateStatement(PowerMockJUnit47RunnerDelegateImpl.java:107)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTest(PowerMockJUnit47RunnerDelegateImpl.java:82)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.runBeforesThenTestThenAfters(PowerMockJUnit44RunnerDelegateImpl.java:288)
at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:87)
at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:50)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.invokeTestMethod(PowerMockJUnit44RunnerDelegateImpl.java:208)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.runMethods(PowerMockJUnit44RunnerDelegateImpl.java:147)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$1.run(PowerMockJUnit44RunnerDelegateImpl.java:121)
at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:34)
at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:44)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.run(PowerMockJUnit44RunnerDelegateImpl.java:123)
at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.run(JUnit4TestSuiteChunkerImpl.java:121)
at org.powermock.modules.junit4.common.internal.impl.AbstractCommonPowerMockRunner.run(AbstractCommonPowerMockRunner.java:53)
at org.powermock.modules.junit4.PowerMockRunner.run(PowerMockRunner.java:59)
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)
Caused by: java.lang.IllegalArgumentException: Cannot subclass final class class java.lang.String
at org.easymock.cglib.proxy.Enhancer.generateClass(Enhancer.java:446)
at org.easymock.cglib.core.DefaultGeneratorStrategy.generate(DefaultGeneratorStrategy.java:25)
at org.easymock.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:216)
at org.easymock.cglib.proxy.Enhancer.createHelper(Enhancer.java:377)
at org.easymock.cglib.proxy.Enhancer.createClass(Enhancer.java:317)
at org.easymock.internal.ClassProxyFactory.createProxy(ClassProxyFactory.java:175)
at org.easymock.internal.MocksControl.createMock(MocksControl.java:113)
at org.easymock.internal.MocksControl.createMock(MocksControl.java:98)
at org.easymock.EasyMock.mock(EasyMock.java:128)
at org.easymock.EasyMock.createMock(EasyMock.java:259)
at org.easymock.internal.Injector.createMocksForAnnotations(Injector.java:130)
at org.easymock.internal.Injector.injectMocks(Injector.java:66)
at org.easymock.EasyMockSupport.injectMocks(EasyMockSupport.java:528)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:95)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:56)
at java.lang.reflect.Method.invoke(Method.java:620)
at org.powermock.reflect.internal.WhiteboxImpl.performMethodInvocation(WhiteboxImpl.java:1899)
at org.powermock.reflect.internal.WhiteboxImpl.doInvokeMethod(WhiteboxImpl.java:801)
at org.powermock.reflect.internal.WhiteboxImpl.invokeMethod(WhiteboxImpl.java:781)
at org.powermock.reflect.Whitebox.invokeMethod(Whitebox.java:466)
at org.powermock.api.extension.listener.AnnotationEnabler.beforeTestMethod(AnnotationEnabler.java:71)
at org.powermock.tests.utils.impl.PowerMockTestNotifierImpl.notifyBeforeTestMethod(PowerMockTestNotifierImpl.java:93)
... 24 more
And my class looks like this.
public String renameOrDeleteDirectory(String Directory, String dirExtn, (short) x){
File workDir = new File(Directory);
String OrigDir = null;
File origDir =null;
boolean renamed = false;
try {
if (null != Directory && Directory.length() > 0 ) {
if(new File(Directory).list().length == 0){
new File(Directory).delete();
}
My test case is like this...
#RunWith(PowerMockRunner.class)
#PrepareForTest(value={Utilities.class, File.class})
public class dirTest1 {
#Test
public void testRenameOrDeleteDirectory1() throws Exception {
mockStatic(File.class);
expectNew(File.class, "C:\\Users\\Desktop\\Docs\\Docs2017_03_07_14_docready").andReturn(workDir);
expect(workDir.list().length == 0).andReturn(true);
expect(workDir.delete()).andReturn(true);
// expect(null != Directory && Directory.length() > 0).andReturn(true);
// expect(new File(Directory).list().length == 0).andReturn(true);
// expect(new File(Directory).delete()).andReturn(true);
PowerMock.replay(File.class, workDir);
Utilities utilities = new Utilities();
utilities.renameOrDeleteDirectory("C:\\Users\\Desktop\\Docs\\Docs2017_03_07_14_docready", "_Ready", (short) 0);
PowerMock.verify(File.class, workDir);
}
}

Answer 1

Hint: your real problem is that you are using new all over the place within your production code. That simply creates hard to test code. And thus you end up looking for PowerMock.
Alternatively, you could create a simple
class FileFactory {
File getFileFor(String fileName) { ...
and use that as field within your class. Now, when you need a File for a certain string, you use that FileFactory instance.
The really nice thing here: that FileFactory can be mocked easily.
So instead of needing PowerMock and all its quirks, you could
improve your design
do full unit-testing ... just with frameworks like EasyMock or Mockito

Answer 2

I solved this error.
It was caused because I was mocking a string along with other mocks.