AssertJ: NoSuchMethodException в softAssert

Я экспериментировал с assertJ в качестве альтернативы текущей библиотеке утверждений hamcrest, которая используется в моем командном проекте. Пока у меня есть следующий класс:

Animal.java

package com.assertions.demo.assertj;

public class Animal {

private Species species;

//no arg constructor
public Animal(){}

public Animal(Species species) {
    this.species = species;
}

public Species getSpecies() {
    return this.species;
}

public enum Species{ 
    DOG(4, true, Environment.LAND), 
    PIGEON(2, false, Environment.AIR), 
    OCTOPUS(8, false, Environment.SEA), 
    ALLIGATOR(4, true, Environment.AMPHIBIOUS);

    private int numLegs;
    private boolean hasTail;
    private Environment environment;

    private Species(int numLegs, boolean hasTail, Environment environment) {
        this.numLegs = numLegs;
        this.hasTail = hasTail;
        this.environment = environment;
    }

    public int getNumLegs(){
        return this.numLegs;
    }

    public boolean hasTail() {
        return this.hasTail;
    }
    public Environment getEnvironment() {
        return this.environment;
    }
}

public enum Environment {
    LAND, SEA, AIR, AMPHIBIOUS
}

}

И я создал для него следующие пользовательские утверждения:

AnimalAssert.java

package com.assertions.demo.assertj;

import org.assertj.core.api.AbstractAssert;
import com.assertions.demo.assertj.Animal.Environment;

public class AnimalAssert extends AbstractAssert<AnimalAssert, Animal> {

public AnimalAssert(Animal actual, Class<AnimalAssert> selfType) {
    super(actual, selfType);
}

public static AnimalAssert assertThat(Animal actual) {
    return new AnimalAssert(actual, AnimalAssert.class);
}

public AnimalAssert hasTail(boolean hasTail) {
    isNotNull();

    if(actual.getSpecies().hasTail() != hasTail) {
        String expectedHasTail = hasTail ? "have a tail" : "not have a tail";
        String actualHasTail = actual.getSpecies().hasTail() ? "does" : "does not";
        failWithMessage("Expected animal to " + expectedHasTail + ", but animal " + actualHasTail + " have a tail");
    }
    return this;
}

public AnimalAssert livesInEnvironment(Environment env) {
    isNotNull();

    if(actual.getSpecies().getEnvironment() != env) {
        failWithMessage("Expected animal environment to be <%s>, but was <%s>", env, actual.getSpecies().getEnvironment());
    }
    return this;
}

public AnimalAssert hasNumberOfLegs(int numLegs) {
    isNotNull();

    if(actual.getSpecies().getNumLegs() != numLegs) {
        failWithMessage("Expected animal to have <%s> legs, but animal has <%s> legs", numLegs, actual.getSpecies().getNumLegs());
    }

    return this;
}
}

В соответствии с функциями AssertJ я предоставил точку входа для вышеупомянутого и пытаюсь добавить функциональность мягкого утверждения:

CustomSoftAssertions.java

package com.demo.assertions.assertj;

import org.assertj.core.api.SoftAssertions;

public class CustomSoftAssertions extends SoftAssertions {

public AnimalAssert assertThat(Animal actual) {
    return proxy(AnimalAssert.class, Animal.class, actual);
}
}

Когда я запускаю следующий тест:

AssertJDemo.java

package com.assertions.demo.assertj;

import org.junit.Test;
import static org.assertj.core.api.Assertions.assertThat;
import com.assertions.demo.assertj.Animal.Environment;
import com.assertions.demo.assertj.Animal.Species;

public class AssertJDemo {
    Animal[] testAnimalArray = new Animal[] {
        new Animal(Species.ALLIGATOR),
        new Animal(Species.DOG),
        new Animal(Species.OCTOPUS),
        new Animal(Species.PIGEON)
    };

    @Test
    public void softAssertWithCustomAssertionsTest() {
        Animal dog = testAnimalArray[1];
        CustomSoftAssertions softAssert = new CustomSoftAssertions();

        softAssert.assertThat(dog).hasTail(false);
        softAssert.assertThat(dog).livesInEnvironment(Environment.AIR);
        softAssert.assertThat(dog).hasNumberOfLegs(8);
    }
}

Я получаю следующую трассировку стека:

org.assertj.core.internal.cglib.core.CodeGenerationException: java.lang.NoSuchMethodException-->com.assertions.demo.assertj.AnimalAssert$$EnhancerByCGLIB$$b5c6715f.<init>(com.assertions.demo.assertj.Animal)
at org.assertj.core.internal.cglib.core.ReflectUtils.getConstructor(ReflectUtils.java:313)
at org.assertj.core.internal.cglib.proxy.Enhancer$EnhancerFactoryData.<init>(Enhancer.java:420)
at org.assertj.core.internal.cglib.proxy.Enhancer.wrapCachedClass(Enhancer.java:709)
at org.assertj.core.internal.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:94)
at org.assertj.core.internal.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:91)
at org.assertj.core.internal.cglib.core.internal.LoadingCache$2.call(LoadingCache.java:54)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at org.assertj.core.internal.cglib.core.internal.LoadingCache.createEntry(LoadingCache.java:61)
at org.assertj.core.internal.cglib.core.internal.LoadingCache.get(LoadingCache.java:34)
at org.assertj.core.internal.cglib.core.AbstractClassGenerator$ClassLoaderData.get(AbstractClassGenerator.java:116)
at org.assertj.core.internal.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:291)
at org.assertj.core.internal.cglib.proxy.Enhancer.createHelper(Enhancer.java:480)
at org.assertj.core.internal.cglib.proxy.Enhancer.create(Enhancer.java:324)
at org.assertj.core.api.SoftProxies.create(SoftProxies.java:42)
at org.assertj.core.api.AbstractSoftAssertions.proxy(AbstractSoftAssertions.java:31)
at com.assertions.demo.assertj.CustomSoftAssertions.assertThat(CustomSoftAssertions.java:18)
at com.assertions.demo.assertj.AssertJDemo.softAssertWithCustomAssertionsTest(AssertJDemo.java:202)
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:497)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Caused by: java.lang.NoSuchMethodException: com.assertions.demo.assertj.AnimalAssert$$EnhancerByCGLIB$$b5c6715f.<init>(com.assertions.demo.assertj.Animal)
at java.lang.Class.getConstructor0(Class.java:3082)
at java.lang.Class.getDeclaredConstructor(Class.java:2178)
at org.assertj.core.internal.cglib.core.ReflectUtils.getConstructor(ReflectUtils.java:309)
... 39 more

Я что-то делаю не так с библиотекой assertJ, или, может быть, я нарушаю что-то специфическое для java, чего я не заметил? Я использую Java 8 с assertJ 3.8.0

РЕДАКТИРОВАТЬ: я обновил класс Animal без конструктора arg на основе первого ответа (cglib требует его), но возникает то же исключение