Obscure issue with mockito-inline: mock object in a test seems to be corrupting mock in later test

[smas321]

This is a very obscure issue, happens only when the planets are aligned. Can you possibly tell me if this is an issue with mockito-inline or if I'm doing something wrong. If its an issue, is there a workaround?

I've simplified what I'm seeing as much as possible. I have 2 tests: Test1 and Test2. I mock MyClass in Test1 (calling clearInlineMocks in @afterclass). In Test2, I mock TestSubInterface which extends TestInterface, which creates an instance of the class I mocked in Test1. The issue is that the constructor for MyClass is not being called when mocking the TestSubInterface in Test2 (I guess because mockito-inline still sees MyClass as a mock from the previous test?). I initialize a variable in the MyClass constructor and later throw an error if it hasn't been initialized, resulting in a java.lang.NoClassDefFoundError when mocking.

HOWEVER, the constructor for MyClass IS called when:

• I mock TestInterface directly instead of TestSubInterface OR
• I do NOT have a default method defined in TestInterface OR
• I use mockito-core instead of mockito-inline

Here are the details:

java.lang.NoClassDefFoundError: Could not initialize class TestSubInterface$MockitoMock$1328129486
        at jdk.internal.reflect.GeneratedSerializationConstructorAccessor2.newInstance(Unknown Source)
        at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500)
        at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481)
        at org.objenesis.instantiator.sun.SunReflectionFactoryInstantiator.newInstance(SunReflectionFactoryInstantiator.java:48)
        at org.objenesis.ObjenesisBase.newInstance(ObjenesisBase.java:73)
        at org.mockito.internal.creation.instance.ObjenesisInstantiator.newInstance(ObjenesisInstantiator.java:21)
        at org.mockito.internal.creation.bytebuddy.InlineByteBuddyMockMaker.doCreateMock(InlineByteBuddyMockMaker.java:360)
        at org.mockito.internal.creation.bytebuddy.InlineByteBuddyMockMaker.createMock(InlineByteBuddyMockMaker.java:318)
        at org.mockito.internal.util.MockUtil.createMock(MockUtil.java:53)
        at org.mockito.internal.MockitoCore.mock(MockitoCore.java:62)
        at org.mockito.Mockito.mock(Mockito.java:1951)
        at org.mockito.internal.configuration.MockAnnotationProcessor.processAnnotationForMock(MockAnnotationProcessor.java:66)
        at org.mockito.internal.configuration.MockAnnotationProcessor.process(MockAnnotationProcessor.java:27)
        at org.mockito.internal.configuration.MockAnnotationProcessor.process(MockAnnotationProcessor.java:24)
        at org.mockito.internal.configuration.IndependentAnnotationEngine.createMockFor(IndependentAnnotationEngine.java:46)
        at org.mockito.internal.configuration.IndependentAnnotationEngine.process(IndependentAnnotationEngine.java:73)
        at org.mockito.internal.configuration.InjectingAnnotationEngine.processIndependentAnnotations(InjectingAnnotationEngine.java:73)
        at org.mockito.internal.configuration.InjectingAnnotationEngine.process(InjectingAnnotationEngine.java:47)
        at org.mockito.MockitoAnnotations.openMocks(MockitoAnnotations.java:82)
        at org.mockito.internal.runners.DefaultInternalRunner$1$1.evaluate(DefaultInternalRunner.java:49)
        at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)
        at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)
        at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)
        at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)
        at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)
        at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
        at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
        at org.mockito.internal.runners.DefaultInternalRunner$1.run(DefaultInternalRunner.java:99)
        at org.mockito.internal.runners.DefaultInternalRunner.run(DefaultInternalRunner.java:105)
        at org.mockito.internal.runners.StrictRunner.run(StrictRunner.java:40)
        at org.mockito.junit.MockitoJUnitRunner.run(MockitoJUnitRunner.java:163)
        at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:252)
        at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:141)
        at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:112)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:564)
        at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:189)
        at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:165)
        at org.apache.maven.surefire.booter.ProviderFactory.invokeProvider(ProviderFactory.java:85)
        at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:115)
        at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:75)

import org.junit.AfterClass;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mock;
import org.mockito.Mockito;
import org.mockito.junit.MockitoJUnitRunner;

@RunWith(MockitoJUnitRunner.Silent.class)
public class Test1 {

    @Mock
    private MyClass foo;

    @AfterClass
    public static void after() {
        Mockito.framework().clearInlineMocks();
    }

    @Test
    public void test() {
        System.out.println("test1!");
    }
}

import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mock;
import org.mockito.junit.MockitoJUnitRunner;

@RunWith(MockitoJUnitRunner.class)
public class Test2 {

    @Mock
    TestSubInterface testInterface;

    @Test
    public void test() {
        System.out.println("test2!");
    }
}

public interface TestSubInterface extends TestInterface {
}

public interface TestInterface {

    MyClass foo = MyClass.createMyNumber(8, "someType").convertTo("someOtherType");

    default boolean someMethod() {
        return true;
    }
}

public class MyClass {

    private final double num;
    private final String type;
    private Object someInternalObj;

    public static MyClass createMyNumber(double m, String  type) {
        return new MyClass(m, type);
    }

    public MyClass(double num, String type) {
        this.num = num;
        this.type = type;
        someInternalObj = new Object();
        System.out.println("MyClass!!!!!!");
    }

    public MyClass convertTo(String to) {
        if(someInternalObj == null)
            throw new RuntimeException("someInternalObj was null");
        return MyClass.createMyNumber(num, to);
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>Test</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>15</maven.compiler.source>
        <maven.compiler.target>15</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.2</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.mockito</groupId>
            <artifactId>mockito-inline</artifactId>
            <version>3.9.0</version>
            <scope>test</scope>
        </dependency>

    </dependencies>

</project>

I'm on windows 10

java --version
java 17.0.1 2021-10-19 LTS
Java(TM) SE Runtime Environment (build 17.0.1+12-LTS-39)
Java HotSpot(TM) 64-Bit Server VM (build 17.0.1+12-LTS-39, mixed mode, sharing)

check that

• [ x] The mockito message in the stacktrace have useful information, but it didn't help
• [ x] The problematic code (if that's possible) is copied here;
  Note that some configuration are impossible to mock via Mockito
• [ x] Provide versions (mockito / jdk / os / any other relevant information)
• [x ] Provide a Short, Self Contained, Correct (Compilable), Example of the issue
  (same as any question on stackoverflow.com)
• [ x] Read the contributing guide

[raphw]

PR for fix is open.

[smas321]

thx @raphw!

[smas321]

hi @raphw do you have any indicative dates on when this bug would be released? or if its available in some other build I can try out

[raphw]

@TimvdLippe Any reason not to trigger a release some time soon?

[TimvdLippe]

It's been about a month since we last released, so I will release one today. Thanks!

[raphw]

I'll do a BB release later today. It contains some Java 17 bug fixes, so you might just wait on that.

[TimvdLippe]

Ha. I just started the release procedure, but I canceled the GitHub action again. Will wait for the BB release 👍

[smas321]

many thanks!

[raphw]

Central is timeouting a lot since everybody tries to fix their log4shell issues. Let's delay a few days.

[TimvdLippe]

I updated our version of BB and starting a new release now.

[TimvdLippe]

4.2.0 is being published to Maven Central atm: https://github.com/mockito/mockito/actions/runs/1587549926