PowerMock's mockStatic() overwrites X.class.y() methods - java

MyClass.java:
package test;
public final class MyClass {
public MyClass() { }
public Package returnPackage() {
return MyClass.class.getPackage();
}
}
TestClass.java:
package test;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
import static org.powermock.api.mockito.PowerMockito.*;
#RunWith(PowerMockRunner.class)
#PrepareForTest(MyClass.class)
public class TestClass {
#Test
public void test() throws Exception {
System.out.println(new MyClass().returnPackage());
mockStatic(MyClass.class);
System.out.println(new MyClass().returnPackage());
}
}
However, this results in:
package test
null
Any MyClass.class method call returns null after PowerMockito.mockStatic(Class). Is there any way to prevent this?

Workaround: I can use the EasyMock-API to set up the static mocks without PowerMockito.mockStatic().

Related

JUnit Testing FaceContext and Session Code

I am attempting to Junit test (IDE: Intellij) Method inside a class called "ManagementDashboardBean" called: (Method name): init()
The method contains FaceContext and Session. I tried the following: https://codenotfound.com/mockito-unit-testing-facescontext-powermock-junit.html
but am still running into issues. I am using Mockito and PowerMockito to help but cannot figure out my init() is saying Null Pointer Exception (NPE). Any guidance would be greatly appreciated. Thanks
P.S the end goal is to show proper test code coverage of this method.
public void init() {
FacesContext context = FacesContext.getCurrentInstance();
HttpSession session = (HttpSession)context.getExternalContext().getSession(false);
userInfo = (UserSessionInfo)session.getAttribute(ConstantsUtil.USER_INFO);
startDt = FDUtil.toDate(FDUtil.toStartOfMonth(userInfo.getCurrentDateMillis()));
endDt = FDUtil.toDate(FDUtil.toEndOfMonth(userInfo.getCurrentDateMillis()));
autoCompleteDate = false;
}
Current JUnit Test
package view.managed.core;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNull;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;
import javax.faces.application.FacesMessage;
import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;
import javax.servlet.http.HttpSession;
import com.sun.jdi.connect.Connector;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.ArgumentCaptor;
import org.mockito.Mock;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
#RunWith(PowerMockRunner.class)
#PrepareForTest({FacesContext.class})
public class ManagementDashboardBeanTest {
private ManagementDashboardBean someBean;
#Mock
private FacesContext facesContext;
#Mock
private ExternalContext externalContext;
#Before
public void setUp() throws Exception {
someBean = new ManagementDashboardBean();
//mock all static methods of FaceContext using PowerMockito
PowerMockito.mockStatic(FacesContext.class);
when(FacesContext.getCurrentInstance()).thenReturn(facesContext);
when(facesContext.getExternalContext()).thenReturn(externalContext);
}
#Test
public void testInitContext() {
//create Captor instances for the userInfo
// ArgumentCaptor<String> clientIdCapture = ArgumentCaptor.forClass(String.class);
// ArgumentCaptor<HttpSession> session = ArgumentCaptor.forClass(HttpSession.class);
// Run the method being tested
// someBean.init();
// verify(facesContext).addMessage(clientIdCapture.capture(), (FacesMessage) session.capture());
}
}
The actual .java source file starts with:
public class ManagementDashboardBean extends EntityManagerService implements Serializable {
private static final Logger LOG = LoggerFactory.getLogger(ManagementDashboardBean.class);
The right after is this, which confuses the hell out of me:
public ManagementDashboardBean() {
init();
}
What I have added so far:
import static org.junit.Assert.*;
import javax.faces.context.FacesContext;
import mil.af.fd.view.managed.services.EntityManagerService;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mockito;
import org.mockito.junit.MockitoJUnitRunner;
import org.powermock.core.classloader.annotations.PrepareForTest;
import java.io.Serializable;
#RunWith(MockitoJUnitRunner.class)
#PrepareForTest({FacesContext.class})
public class ManagementDashboardBeanTest {
private ManagementDashboardBean dashboard;
private Serializable serializableMock;
private EntityManagerService entityManagerServiceMock;
#BeforeClass
public static void before() {
System.out.println("Before Class");
}
#Before
public void setUp() throws Exception {
entityManagerServiceMock = Mockito.mock(EntityManagerService.class);
serializableMock = Mockito.mock(Serializable.class);
dashboard = new ManagementDashboardBean(serializableMock);
}
#Test
public void testInitContext() {
// dashboard.init();
System.out.println("Test 1");
}
}

Mockito: Intercepting method call without reference to object

I want to test the following example code:
public class Example {
...
public void doStuff() {
...
Lift lift = new Lift();
lift.call(5);
...
}
...
}
How can I 'intercept' lift.call(5)?
Generally I would use when(lift.call(anyInt()).thenReturn(...), but I have no reference to the Lift object.
You can't do it with mockito alone. The cleanest solution is to refactor your code so you can have access to it. However if that's not an option then "power mockito" is what you want. Grab "powermock-api-mockito"+"powermock-module-junit4" and then something like this will do the trick:
import static org.mockito.Mockito.verify;
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(Example.class)
public class ExampleTest {
private Example testSubject;
#Mock
private Lift lift;
#Test
public void testDoStuff() throws Exception {
testSubject.doStuff();
verify(lift).call(5);
}
#Before
public void setUp() throws Exception {
MockitoAnnotations.initMocks(this);
PowerMockito.whenNew(Lift.class).withNoArguments().thenReturn(lift);
testSubject = new Example();
}
}
Can you modify the Example class? If yes, the simplest way would be to extract the Lift dependency and provide it via constructor. Like this:
public class Example {
private final Lift lift;
public Example(Lift lift) {
this.lift = lift;
}
public void doStuff() {
this.lift.call(5);
}
}
Then you can stub lift as you want since now you have access to the instance.

How to mock nested static methods using PowerMockito?

How can I mock nested static methods using PowerMockito?
The following is a very simple example on how I want to use it.
Class:
public class SomeClass {
public static String someMethodA(){
//some very important codes here
return someMethodB();
}
private static String someMethodB(){
return someMethodC();
}
private static String someMethodC(){
return "Some Text";
}
}
Already tried the following but did not work:
PowerMockito.mockStatic(SomeClass.class);
PowerMockito.stub(PowerMockito.method(SomeClass.class, "someMethodB")).toReturn("Some Other Text");
I wanted to run someMethodA() as is, which is why I want to stub someMethodB() instead. Is there anyway I can do this? Hoping that there is a way without having to modify the access modifiers because the codes I am working with are legacy codes.
You can spy the private static methods.
Tested in JUnit4
import static org.junit.Assert.assertEquals;
import static org.powermock.api.mockito.PowerMockito.spy;
import static org.powermock.api.mockito.PowerMockito.when;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
#RunWith(PowerMockRunner.class)
#PrepareForTest(SomeClass.class)
public class SomeClassTest {
#Test
public void test() throws Exception {
spy(SomeClass.class);
when(SomeClass.class, "someMethodB").thenReturn("Some Other Text");
assertEquals("Some Other Text", SomeClass.someMethodA());
}
}

Stubbing static methods in Mockito 2 throws InvalidUseOfMatchersException

I have a class where I'm using Powermock + Mockito to suppress a static method in a utility class. It works fine with Powermock 1.6.2 and Mockito 1.10.19, but I've been tasked with moving to Java 10 (JRE: we're still compiling with Java 8) and so I've moved to Powermock 2 (currently in beta) and Mockito 2.16.1. Now, I consistently get org.mockito.exceptions.misusing.InvalidUseOfMatchersException:
Misplaced or misused argument matcher detected here.
A simple example, MyMockito.java:
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
import java.lang.reflect.Method;
import static org.mockito.Mockito.any;
import static org.powermock.api.mockito.PowerMockito.spy;
import static org.powermock.api.mockito.PowerMockito.when;
import static org.powermock.api.support.membermodification.MemberMatcher.method;
import static org.powermock.api.support.membermodification.MemberModifier.suppress;
#RunWith(PowerMockRunner.class)
#PrepareForTest(StringMeasurer.class)
public class MyMockito {
#Test
public void testSuppressMethod() throws Exception {
spy(StringMeasurer.class);
Method measure = method(StringMeasurer.class, "measure", String.class);
suppress(measure);
when(StringMeasurer.class, measure)
.withArguments(any(String.class))
.thenReturn(10);
System.out.println(StringMeasurer.measure("Hello"));
}
And StringMeasurer.java:
public class StringMeasurer {
private StringMeasurer() {}
public static int measure(String s) {
return s.length();
}
}
}
I'm assuming that either there have been some changes to how matchers can be used to match arguments in stubbed static methods, or else this should never have worked and somehow got through in Mockito 2 (or possibly this is a bug in the Powermock beta). Can anyone provide me some insight into what I'm doing wrong?
Working solution for PowerMock 2.0.0-beta.5:
import static org.mockito.ArgumentMatchers.any;
import static org.powermock.api.mockito.PowerMockito.when;
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(StringMeasurer.class)
public class MyMockito {
#Test
public void testSuppressMethod() throws Exception {
PowerMockito.mockStatic(StringMeasurer.class);
when(StringMeasurer.measure(any(String.class))).thenReturn(10);
System.out.println(StringMeasurer.measure("Hello"));
}
}
More details can be found in the official PowerMock documentation: Mocking Static Method
The question uses the PowerMockito.spy() method, which is required for partial mocking, although the example given only has one static method, so that's not necessary here. Here's a working solution that uses partial mocking for an extended example:
MyMockito.java:
import org.junit.Test;
import org.junit.runner.RunWith;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
import java.lang.reflect.Method;
import java.util.List;
import static junit.framework.Assert.assertEquals;
import static org.mockito.Mockito.*;
import static org.powermock.api.support.membermodification.MemberMatcher.method;
import static org.powermock.api.mockito.PowerMockito.doReturn;
import static org.powermock.api.mockito.PowerMockito.spy;
#RunWith(PowerMockRunner.class)
#PrepareForTest(StringMeasurer.class)
public class MyMockito {
#Test
public void testSuppressMethod() throws Exception {
spy(StringMeasurer.class);
Method measure = method(StringMeasurer.class, "measure", String.class);
doReturn(10).when(StringMeasurer.class, measure)
.withArguments(any(String.class));
System.out.println(StringMeasurer.measure("Hello"));
List<String> dummy = StringMeasurer.dummy(5);
assertEquals(5, dummy.size());
dummy.forEach(System.out::println);
}
}
And StringMeasurer.java:
import java.util.ArrayList;
import java.util.List;
public class StringMeasurer {
private StringMeasurer() {}
public static int measure(String s) {
return s.length();
}
public static List<String> dummy(int size) {
List<String> list = new ArrayList<>();
for (int i = 0; i < size; i++) {
list.add("" + i);
}
return list;
}
}
Note that, in this case, the accepted solution would mock the StringMeasurer.dummy() method as well, returning an empty list, and the test would fail on the assertEquals().

Mocking final class with parameterized constructor

I have a final class as below
public class firstclass{
private String firstmethod(){
return new secondclass("params").somemethod();
}
}
public final class secondclass{
secondclass(String params){
//some code
}
public String somemethod(){
// some code
return somevariable";
}
}
I have to here test first class so I have mocked this as below
secondclass classMock = PowerMockito.mock(secondclass .class);
PowerMockito.whenNew(secondclass .class).withAnyArguments().thenReturn(classMock);
Mockito.doReturn("test").when(classMock).somemethod();
But it is not mocking as I expected can anyone help me?
The method firstclass.firstmethod() is private method. So try to test this method through public method in which it is getting called.
You can mock SecondClass and its final method using #RunWith(PowerMockRunner.class) and #PrepareForTest(SecondClass.class) annotations.
Please see below the working code:
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mockito;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
#RunWith(PowerMockRunner.class)
#PrepareForTest(SecondClass.class)
public class FirstClassTest{
#Before
public void init() {
}
#After
public void clear() {
}
#Test
public void testfirstmethod() throws Exception{
SecondClass classMock = PowerMockito.mock(SecondClass.class);
PowerMockito.whenNew(SecondClass.class).withAnyArguments().thenReturn(classMock);
Mockito.doReturn("test").when(classMock).somemethod();
new FirstClass().firstmethod();
}
}
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