We Keep Coding

org.powermock.api.mockito.ClassNotPreparedException in Static class mocking

I am writing a unit test to mock a static method in the verticle but getting ClassNotPreparedException always. I think that its only possible to mock this way if only the class is static, but i have non static class. What am i missing?
I have tried various solutions like using #rule or #PowerMockIgnore
//myVerticleTest.java
package com.blabla.me.verticles;
import static com.google.common.truth.Truth.assertThat;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import io.vertx.core.Vertx;
import io.vertx.junit5.VertxTestContext;
import io.vulpx.VulpxTestBase;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PowerMockIgnore;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
import org.junit.runner.RunWith;
import com.blabla.me.verticles.AdditionalInformationCardVerticle;
import org.powermock.modules.junit4.rule.PowerMockRule;
import org.junit.Rule;
import com.blabla.me.verticles.st;
#RunWith(PowerMockRunner.class)
#PrepareForTest({ st.class })
#PowerMockIgnore({"org.mockito.*"})
public class myVerticleTest extends VulpxTestBase {
#Rule public PowerMockRule rule = new PowerMockRule();
private Vertx vertx;
private AdditionalInformationCardVerticle dummy;
#BeforeEach
#PrepareForTest({ st.class })
public void setUp(VertxTestContext testContext) throws Exception {
vertx = Vertx.vertx();
try {
PowerMockito.mockStatic(st.class);
PowerMockito.when(st.createClient()).thenReturn("kk");
//deploying verticle
dummy = new AdditionalInformationCardVerticle();
vertx.deployVerticle(dummy, testContext.completing());
} catch (Exception e) {
System.out.println("heyyy eroorrr : " + e);
}
}
#Test
#PrepareForTest({ st.class })
public void justnormaltest() {
cla ownclass = new cla();
String k = ownclass.createfromclass();
assertThat("kk").isEqualTo(k);
}
}
// st.java
public class st {
public static String createClient() {
return "kk";
}
}
// cla.java
public class cla {
public String createfromclass() {
return st.createClient();
}
}
I expect it to run the assertion but i always get below excpetion:
"org.powermock.api.mockito.ClassNotPreparedException:
The class com.sap.me.verticles.st not prepared for test.
To prepare this class, add class to the '#PrepareForTest' annotation.
In case if you don't use this annotation, add the annotation on class or method level. "

Here:
#PrepareForTest({ st.class })
That one goes to exactly one place: in front of your test class public class myVerticleTest.
And hint: instead of adding more and more "things" to not working code: pick any good documentation, and try to follow that to the last ; in the example code (instead of assuming that adding more and more things here or there would help).
One good starting point: the official documentation on static mocking.
And of course, the usual caveat: consider not learning about PowerMock in the first place. Instead focus on writing "easy to test" code. Far too often, people think PowerMock(ito) is the answer to their problem. When their problem in reality is their inability to write "easy to test" production code.

Mockito - mock library call

I have the following structure
public class classAImpl implements classA {
public ClassC getTarget(Classc cObj) {
// library call
RegistryLib.init();
// some more code to construct cObj with more info
return cObj
}
}
// Registry Library Class
Class RegistryLibClass{
public void init() {
ClassD.builder.build();
}
}
My test class is trying to test a method which calls getTarget() method written above. I want to completely avoid executing getTarget() method which I am not been able even after mocking it. So far I have tried the following:
Class Testclass {
#Before
public void setUp() {
Testclass mock = PowerMockito.mock(Testclass.class);
PowerMockito.when(mock.getTarget(cObj)).thenReturn(cObj);
}
private ClassC getTarget(cObj) {
return cObj;
}
}
Any help is appreciated!

Assuming you want to test a method in Class B that calls getTarget from Class A, you would do this,
B b = new B();
A a = Mockito.mock(A.class);
C c = new C();
Mockito.when(a.getTarget(Mockito.any(C.class)).thenReturn(c);
boolean isPresent = b.someMethodToTest();
assertEquals("someMethodToTest was supposed to return true", true/*expected*/, isPresent);
Edit#1
You need to use Powermockito to mock the static method to return nothing as mentioned here
#PrepareForTest(RegistryLibClass.class) //at the top of the class
//inside your test
PowerMockito.mockStatic(RegistryLibClass.class);
Mockito.when(RegistryLibClass.init()).doNothing();

Disclaimer - I'm not that familiar with mockito, but wouldn't you normally mock the class you want to avoid using? Like this:
class Testclass {
#Before
public void setUp() {
//create some mock of expected cObj here to be returned.
classAImpl mock = PowerMockito.mock(classAImpl.class);
PowerMockito.when(
mock.getTarget(cObj.class /*Shouldn't this be class call?*/))
.thenReturn(cObj);
}
}
And then you would inject mock as dependency into the object that uses it and that you want to test.
If I'm wrong then feel free to ignore me, but thats how other mocking libraries I used worked. I'd advise you to go read some tutorials about mocking for tests regardless.
As side note, use of Class and class in names made this example extremely difficult to understand.

Your example is very confusing as you are trying to mock your test class itself instead of the main class.
Also you have mentioned that you are trying to test a method which calls getTarget() method, but I don't see any method in your class that calls getTarget() method.
I have put down a simple example below for your understanding. Let me know if this helps.
ClassA
public class ClassA {
public String method1() {
return "ClassA -> method1";
}
public static String method2() {
return "ClassA -> method2";
}
}
ClassB calls Class A methods
public class ClassB {
public void method1() {
System.out.println("ClassB -> method1");
new ClassA().method1();
ClassA.method2();
}
}
ClassB Test
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
#RunWith(PowerMockRunner.class)
#PrepareForTest(ClassA.class)
public class ClassBTest {
#Mock
ClassA mock;
#Before
public void setUp() throws Exception {
// Initialize mocks
MockitoAnnotations.initMocks(this);
// This is for mocking new objects
PowerMockito.whenNew(ClassA.class).withNoArguments().thenReturn(mock);
PowerMockito.when(mock.method1()).thenReturn("Mocked Method 1");
// This is for mocking static methods
PowerMockito.mockStatic(ClassA.class);
PowerMockito.when(ClassA.method2()).thenReturn("Mocked Method 2");
}
#Test
public void testMeth() {
System.out.println(new ClassA().method1()); // Prints - Mocked Method 1
System.out.println(ClassA.method2()); // Prints - Mocked Method 2
}
}

Exception while using PowerMockito with static method

I want to mock a static method using PowerMockito,
public class DepedencyService {
public static int getImportantValue() {
return -4;
}
}
public class Component {
public int componentMethod() {
return DepedencyService.getImportantValue();
}
}
but it is giving me an exception.
import static org.testng.Assert.assertEquals;
import org.easymock.EasyMock;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
#RunWith(PowerMockRunner.class)
#PrepareForTest(DepedencyService.class)
public class ComponentTest {
#Test
public void testComponentMethod() {
Component c = new Component();
PowerMockito.mockStatic(DepedencyService.class);
EasyMock.expect(DepedencyService.getImportantValue()).andReturn(1);
assertEquals(1, c.componentMethod());
}
}
The exception :-
java.lang.IllegalStateException: no last call on a mock available at
org.easymock.EasyMock.getControlForLastCall(EasyMock.java:520) at
org.easymock.EasyMock.expect(EasyMock.java:498)
Can anyone please help me? Why is this failing? I am new to PowerMockito and does not know what to do here!

Your main problem is that you're writing STUPID code (like most of us did at the beginning) where you rather should write SOLID code.
Using Powermock is just a surrender to this bad design.
Yes, classes having only static methods are called utility classes.
But you should get over this misconception that classes providing common behavior should have (only) static methods.
As a rule of thumb there should be only one non private static method in your entire program, and this is main().

You appear to be mixing mocking frameworks.
You need to properly arrange the static dependencies before exercising the test
Since PowerMockito is used to mock the static class then you should use Mockito to arrange the expected behavior
For example
#RunWith(PowerMockRunner.class)
#PrepareForTest(DepedencyService.class)
public class ComponentTest {
#Test
public void testComponentMethod() {
//Arrange
int expected = 1;
PowerMockito.mockStatic(DepedencyService.class);
Mockito.when(DepedencyService.getImportantValue()).thenReturn(expected);
Component subject = new Component();
//Act
int actual = subject.componentMethod();
//Assert
assertEquals(expected, actual);
}
}
That said, I would advise not having your code tightly coupled to static dependencies. It makes for difficult to test code.

How to run PowerMock on dynamically created TestCase

I was trying to mock my test suites. My test framework creates test cases by scanning test files on disk. So each time the test cases are dynamically created.
I was trying to use PowerMock. Below is the thing I tried first.
public class GroupTestcase_T extends TestSuite {
static void run() {
scan();
junit.textui.TestRunner.run(g);
}
static void scan() {
// scan disk
for (MyTestCase t : tests) { addTest(t); }
}
}
#RunWith(PowerMockRunner.class)
#PrepareForTest(ClassToStub.class)
public class MyTestCase extends TestCase {
public MyTestCase(TestInfo info) {...}
#Override
protected void setUp() throws Exception {
PowerMockito.mockStatic(ClassToStub.class);
when(ClassToStub.methodToStub())
.thenReturn(new FakeProxy());
}
#Test
public void test() throws Exception {
// Test!
}
}
Above code seems not working:
Also, this error might show up because:
1. you stub either of: final/private/equals()/hashCode() methods.
Those methods cannot be stubbed/verified.
2. inside when() you don't call method on mock but on some other object.
3. the parent of the mocked class is not public.
It is a limitation of the mock engine.
I traced the code and found that PowerMockRunner are not called at all.
Also I tried manually force Junit to run it with PowerMockRunner:
Result result = junit.run(new PowerMockRunner(MyTestCase.class));
PowerMockRunner has only one constructor that takes the test class as parameter. My test cases are different each time but all share the same class.
Any idea how to use PowerMock if TestCase are dynamically created?
I was using Junit 4 / PowerMock 1.5

You can generate your tests with the parameterized tests feature and apply the #PowerMockRule.
import static org.junit.Assert.assertTrue;
import java.util.Arrays;
import java.util.Collection;
import org.junit.Rule;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
import org.junit.runners.Parameterized.Parameters;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.rule.PowerMockRule;
#RunWith(Parameterized.class)
#PrepareForTest(ClassToStub.class)
public class MyTestCase{
#Parameters
public static Collection<Object[]> scan() {
return Arrays.asList(new Object[][] {
{ new TestInfo() }, { new TestInfo() } });
}
#Rule
public PowerMockRule rule = new PowerMockRule();
public MyTestCase(TestInfo info) {
// ...
}
#Test
public void test() throws Exception {
PowerMockito.mockStatic(ClassToStub.class);
PowerMockito.when(ClassToStub.methodToStub()).thenReturn(new FakeProxy());
assertTrue(ClassToStub.methodToStub() instanceof FakeProxy);
}
}
Beware, in your example, you are mixing junit 3 (extends TestSuite, protected setUp) and junit 4 (#Test) test definitions.

How do I mock static methods in a class with easymock?

Suppose I have a class like so:
public class StaticDude{
public static Object getGroove() {
// ... some complex logic which returns an object
};
}
How do I mock the static method call using easy mock? StaticDude.getGroove().
I am using easy mock 3.0

Not sure how to with pure EasyMock, but consider using the PowerMock extensions to EasyMock.
It has a lot of cool functions for doing just what you need -
https://github.com/jayway/powermock/wiki/MockStatic

Easymock is a testing framework for "for interfaces (and objects through the class extension)" so you can mock a class without an interface. Consider creating an interfaced object with an accessor for your static class and then mock that acessor instead.
EDIT: Btw, I wouldn't recommend doing static classes. It is better to have everything interfaced if you are doing TDD.

Just in Case PowerMock is unavailable for any reason:
You could move the static call to a method, override this method in the instantiation of the tested class in the test class, create a local interface in the test class and use its method in the overidden method:
private interface IMocker
{
boolean doSomething();
}
IMocker imocker = EasyMock.createMock(IMocker.class);
...
#Override
void doSomething()
{
imocker.doSomething();
}
...
EasyMock.expect(imocker.doSomething()).andReturn(true);

Generally speaking, it is not possible to mock a static method without using some sort of accessor, which seems to defeat the purpose of using a static method. It can be quite frustrating.
There is one tool that I know of called "TypeMock Isolator" which uses some sort of Satanic Magic to mock static methods, but that tool is quite expensive.
The problem is, I know of no way to override a static method. You can't declare it virtual. you can't include it in an interface.
Sorry to be a negative nelly.

Adding an exemple on how to implements static mock along regular mock of injected classes with EasyMock / PowerMock, since the linked exemple only shows static mock.
And with the PowerMockRunner the #Mock services are not wired on the #TestSubject service to test.
Let say we have a service we want to test, ServiceOne :
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
#Service
public class ServiceOne {
#Autowired
private ServiceTwo serviceTwo;
public String methodToTest() {
String returnServ2 = serviceTwo.methodToMock();
return ServiceUtils.addPlus(returnServ2);
}
}
Which calls another service that we will want to mock, ServiceTwo :
import org.springframework.stereotype.Service;
#Service
public class ServiceTwo {
public String methodToMock() {
return "ServiceTwoReturn";
}
}
And which calls a final class static method, ServiceUtils :
public final class ServiceUtils {
public static String addPlus(String pParam) {
return "+" + pParam;
}
}
When calling ServiceOne.methodToTest() we get "+ServiceTwoReturn" as a return.
Junit Test with EasyMock, mocking only the injected ServiceTwo Spring service :
import static org.easymock.EasyMock.expect;
import static org.easymock.EasyMock.replay;
import static org.easymock.EasyMock.verify;
import static org.junit.Assert.assertEquals;
import org.easymock.EasyMockRunner;
import org.easymock.Mock;
import org.easymock.TestSubject;
import org.junit.Test;
import org.junit.runner.RunWith;
#RunWith(EasyMockRunner.class)
public class ExempleTest {
#TestSubject
private ServiceOne serviceToTest = new ServiceOne();
#Mock
private ServiceTwo serviceMocked;
#Test
public void testMethodToTest() {
String mockedReturn = "return2";
expect(serviceMocked.methodToMock()).andReturn(mockedReturn);
replay(serviceMocked);
String result = serviceToTest.methodToTest();
verify(serviceMocked);
assertEquals("+" + mockedReturn, result);
}
}
Junit Test with EasyMock & PowerMock, mocking the injected ServiceTwo Spring service but also the final class and its Static method :
import static org.easymock.EasyMock.expect;
import static org.junit.Assert.assertEquals;
import static org.powermock.api.easymock.PowerMock.createMock;
import static org.powermock.api.easymock.PowerMock.mockStatic;
import static org.powermock.reflect.Whitebox.setInternalState;
import org.easymock.Mock;
import org.junit.Before;
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;
#RunWith(PowerMockRunner.class)
#PrepareForTest(ServiceUtils.class)
public class ExempleTest {
private ServiceOne serviceToTest;
private ServiceTwo serviceMocked;
#Before
public void setUp() {
serviceToTest = new ServiceOne();
serviceMocked = createMock(ServiceTwo.class);
// This will wire the serviced mocked into the service to test
setInternalState(serviceToTest, serviceMocked);
mockStatic(ServiceUtils.class);
}
#Test
public void testMethodToTest() {
String mockedReturn = "return2";
String mockedStaticReturn = "returnStatic";
expect(serviceMocked.methodToMock()).andReturn(mockedReturn);
expect(ServiceUtils.addPlus(mockedReturn)).andReturn(mockedStaticReturn);
PowerMock.replayAll();
String result = serviceToTest.methodToTest();
PowerMock.verifyAll();
assertEquals(mockedStaticReturn, result);
}
}