[FIXED] Null pointer exception when jenkins version is set to 2.X

Issue

I have a plugin with jenkins version set to 1.580.3.And when I upgrade the jenkins version to 1.642.3<=version , it is throwing a null pointer exception.Below is the stacktrace

java.lang.NullPointerException
        at hudson.model.Label.hashCode(Label.java:528)
        at java.util.HashMap.hash(HashMap.java:338)
        at java.util.HashMap.put(HashMap.java:611)
        at java.util.HashSet.add(HashSet.java:219)
        at java.util.Collections.addAll(Collections.java:5401)
        at com.google.common.collect.Sets.newHashSet(Sets.java:183)
        at com.ericsson.oss.axis.ATest.setUp(ATest.java:45)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.junit.internal.runners.MethodRoadie.runBefores(MethodRoadie.java:132)
        at org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters(MethodRoadie.java:95)
        at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.executeTest(PowerMockJUnit44RunnerDelegateImpl.java:294)
        at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTestInSuper(PowerMockJUnit47RunnerDelegateImpl.java:127)
        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:282)
        at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:86)
        at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:49)
        at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.invokeTestMethod(PowerMockJUnit44RunnerDelegateImpl.java:207)

below is my code

import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.nullValue;
import static org.hamcrest.core.Is.is;
import static org.mockito.Mockito.doReturn;
import static org.mockito.Mockito.when;
import java.util.ArrayList;
import java.util.List;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.jvnet.jenkins.plugins.nodelabelparameter.LabelParameterValue;
import org.mockito.Answers;
import org.mockito.Mock;
import org.powermock.api.mockito.PowerMockito;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;
import com.XXXXX.JenkinsUtils;(internal)
import com.google.common.collect.Sets;
import hudson.model.AbstractBuild;
import hudson.model.Label;
import hudson.model.ParameterValue;
import hudson.model.ParametersAction;
import jenkins.model.Jenkins;
        @RunWith(PowerMockRunner.class)
        @PrepareForTest( JenkinsUtils.class)
            public class A{
                 @Mock
                private Label label;
                @Mock
                private Jenkins jenkins;
                @Mock(answer = Answers.RETURNS_DEEP_STUBS)
                private AbstractBuild build;


                @Before
                public void setUp() {
                    PowerMockito.mockStatic(JenkinsUtils.class);
                    try {
                        doReturn(Sets.newHashSet(label)).when(jenkins).getLabels();
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            }

    @RunWith(PowerMockRunner.class)
    @PrepareForTest(NodeLabelParameterUtils.class )    
    public class B{
           private BaselineDefinedMessageDispatcher unit;
            private BuildData buildData = new BuildData();
            private MyBuildDetails myBuildDetails;

            @Mock(answer = Answers.RETURNS_DEEP_STUBS)
            private AbstractBuild build;
            @Mock
            private BuildLogger buildLogger;
            @Mock
            private Label label;
            @Mock
            private Computer computer;
            @Mock
            private PretendSlave node;
            @Mock
            private FreeStyleProject project;
            @Mock
            private Jenkins jenkins;
            @Mock
            private EnvironmentVariableResolver envVarsResolver;


            @Before
            public void setUp() throws IOException, InterruptedException, Descriptor.FormException {
                unit = spy(new BaselineDefinedMessageDispatcher(null, null));
                unit.setBuildLogger(mock(BuildLogger.class));

                MyBuildDetails = mock(MyBuildDetails.class);

                doReturn("expectedSlaveHost").when(unit).getHostNameFromSlave(any(Node.class));
                doReturn(project).when(build).getProject();
                doReturn(Sets.<Node>newHashSet(node)).when(label).getNodes();
                doReturn(node).when(build).getBuiltOn();
                doReturn(jenkins).when(unit).getJenkinsInstance();

                doReturn(Sets.newHashSet(label)).when(jenkins).getLabels();

                PowerMockito.mockStatic(A.class);

                when(envVarsResolver.processString(anyString())).thenAnswer(new Answer<String>() {
                    @Override
                    public String answer(InvocationOnMock invocationOnMock) throws Throwable {
                        return (String) invocationOnMock.getArguments()[0];
                    }
                });
        }

The following dependencies are being used

        powermock-api-mockito - 1.6.3
        mockito-core          - 1.9.5
        junit                 - 4.11
        java                  - 1.8
        jenkins.version       - 1.642.3

I get the error exactly at doReturn(Sets.newHashSet(label)).when(jenkins).getLabels(); in class A. This is a maven project and when jenkins version is set to 1.580.3 mvn clean install is success but when it is version>=1.642.3 it is failing. My aim is to upgrade jenkins verison to 2.X.I went through manyworkarounds in stackoverflow but nothing worked Any help is appreciated

Solution

Edit:

Looks like my orignal answer was just incorrect.

The NPE comes from the fact that the abstract Label class has a constructor parameter called name. This parameter is used to calculate the hashcode of the label.

If you mock it this name is null and you get the NPE.

The question now is do you need to create a mock of this or can you actually use a real instance? In the exmaple below I just used one of the implementations of that class LabelAtom. If a mock is required because you need to define some behaviour on the object that you can not get otherwise, you probably have to use a spy.

(Tested with org.jenkins-ci.main:jenkins-core:2.85)

import static org.mockito.Mockito.doReturn;

import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mock;
import org.powermock.modules.junit4.PowerMockRunner;

import com.google.common.collect.Sets;

import hudson.model.Label;
import hudson.model.labels.LabelAtom;
import jenkins.model.Jenkins;

@RunWith(PowerMockRunner.class)
public class Test {

    @Mock
    private Jenkins jenkins;

    private Label label;

    @Before
    public void setUp() {

        Assert.assertNotNull(jenkins);

        label = new LabelAtom("someName");

        // or if a mock is required
        //label = Mockito.spy(new LabelAtom("someName"));

        doReturn(Sets.newHashSet(label)).when(jenkins).getLabels();
    }

    @Test
    public void test() {

    }
}

---

Regarding the WithOrWithoutExpectedArguments I was not able to reproduce that one.

Answered By - second