PowerMock:: [java.lang.IllegalStateException: no last call on a mock available]

Question

To mock a static method powermock giving an exception while expect().

@Test
public void testRegistrarService()
{
   mockStatic(IdGenerator.class);
   expect(IdGenerator.generateNewId()).andReturn(42L);
   long actualId=serTestObj.registerService();
   replay(IdGenerator.class);
   verify(IdGenerator.class);
   assertEquals(42L,actualId);
 }


public class ServiceRegistrator
{
public long registerService()
{
    long id = IdGenerator.generateNewId();
    return id;
 }
}

public class IdGenerator
{
  public static long generateNewId()
  {
    return System.currentTimeMillis();
  }
}

Exception is:

java.lang.IllegalStateException: no last call on a mock available
at org.easymock.EasyMock.getControlForLastCall(EasyMock.java:521)
at org.easymock.EasyMock.expect(EasyMock.java:499)
at  home.powermock.testServiceRegistrator.testRegistrarService(testServiceRegistrator.java:51)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at com.intellij.rt.execution.junit2.JUnitStarter.main(JUnitStarter.java:31)

how to mock staic method,while m using powerMock i'm using intelliJ idea,how to resolve that exception.

Answer 1

Your code is missing the annotation

@PrepareForTest(IdGenerator.class)

Answer 2

In my case I was missing the following method in my test class

   @ObjectFactory
   /**
    * Configure TestNG to use the PowerMock object factory.
    */
   public IObjectFactory getObjectFactory() {
      return new org.powermock.modules.testng.PowerMockObjectFactory();
   }

Once I added it, I got rid of the "no last call on a mock available" error.

Answer 3

You need to put the replay before the actual call to the method.

EDIT: I think part of the problem may be caused because of your imports. Try not to import static powermock and static easymock (I've found that I often confuse myself and forget which one I need to call replay on).

Try running the following code. If it doesn't run correctly, then it may be because of a problem with the particular version of PowerMock/EasyMock/Junit that you have.

TestClass:

import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.easymock.PowerMock;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

import static org.easymock.EasyMock.*;

import static org.junit.Assert.*;
@RunWith(PowerMockRunner.class)
@PrepareForTest(IdGenerator.class)
public class TestClass {

@Test
public void testRegistrarService()
{
    ServiceRegistrator serTestObj = new ServiceRegistrator();

    PowerMock.mockStatic(IdGenerator.class);
    expect(IdGenerator.generateNewId()).andReturn(42L);
    PowerMock.replay(IdGenerator.class);
    long actualId=serTestObj.registerService();
    PowerMock.verify(IdGenerator.class);
    assertEquals(42L,actualId);
 }
}

IdGenerator:

public class IdGenerator {
     public static long generateNewId()
      {
        return System.currentTimeMillis();
      }
}

ServiceRegistrator:

public class ServiceRegistrator {
    public long registerService()
    {
        long id = IdGenerator.generateNewId();
        return id;
     }
}

Answer 4

This question has been here for a long time but I'll try to give to it an aswer to explain what i did to resolve this problem.

First of all you have to use these two annotations:

@RunWith(PowerMockRunner.class)

This annotation let the current test class know what to use to run his tests, this is useful because we can use PowerMockRunner instead of JUnitRunner

@PrepareForTest(IdGenerator.class)

This annotation is used to prepare the class "IdGenerator" to be used in the test, prepare means that we will be able to mock the static methods as we do to the public methods

After added these two annotations we have to be sure we are using the right packages provided by PowerMock:

1) PowerMock:

• Import: import org.powermock.api.easymock.PowerMock;

• Use: We will use PowerMock to mock (and not only) our static method with the following code line

  PowerMock.mockStatic(IdGenerator.class);

2) EasyMock:

• Import: import org.easymock.EasyMock;

• Use: We are going to use EasyMock to fake our object to be returned by our static method:

  EasyMock.expect(IdGenerator.generateNewId()).andReturn(42L);

These was two examples on what are used PowerMock and EasyMock, and here I'll try to explain the code and what it does:

mockStatic(IdGenerator.class);
//We mock our IdGenerator class which have the static object

expect(IdGenerator.generateNewId()).andReturn(42L);
//We fake our method return object, when we'll call generateNewId()
//method it will return 42L
//With expecting we "record" our this method and we prepare it to be     
//changed (it will return our decided value)

replay(IdGenerator.class);
//We go to perform our methods "registered" with the expect method
//inside the IdGenerator class, in this case with replay we just apply
//the changes of the expect to the method generateNewId()

long actualId = serTestObj.registerService();
//We create our object (which inside have a non static method that
//use generateNewId() static method)

verify(IdGenerator.class);
//We verify that the our faked method have been called

assertEquals(42L,actualId);
//We see if the two values are matching

Pay attention because replay must be used before you create the new object (actualId in this example) that will call the static faked methods.

Also do a lot of attention on what you are importing, for a distraction i was using

PowerMockito.mockStatic(className.class);
//from import org.powermock.api.mockito.PowerMockito;

Instead of

PowerMock.mockStatic(className.class);
//from import org.powermock.api.easymock.PowerMock;

I hope that this answer is clear and complete

By the way here i'll refer you to some useful links:

PowerMock Static Documentation on GitHub

Mvn Repository PowerMock Libraries

See you :D