JavaのprivateなインナークラスをGroovyで何事も無かったかのようにテスト

A.java

package foobar;

public class A {

    private static class B {
        
        private static String staticMethod() {
            return "static method";
        }

        private String instanceMethod() {
            return "instance method";
        }

    }

    private class C {
        
        private String instanceMethod() {
            return "instance method";
        }

    }

}

A_and_specs.groovy

//
//  using Groovy Console Java WebStart
//


@Grab('org.spockframework:spock-core:0.5-groovy-1.7')
@Grab(group='junit', module='junit', version='4.8.2')

public class A {
    private static class B {
        
        private static String staticMethod() {
            return "static method";
        }
        private String instanceMethod() {
            return "instance method";
        }
    }

    private class C {
        private String instanceMethod() {
            return "instance method";
        }
    }
}


import spock.lang.*

class ASpec extends Specification{

    def "private static class#static method"() {
        expect:
            A.B.staticMethod() == 'static method'
    }

    def "private static class#instance method"() {
        expect:
            new A.B().instanceMethod() == 'instance method'
    }

    def "private class#instance method"() {
        expect:
            new A.C().instanceMethod() == 'instance method'
    }

}
new org.junit.runner.JUnitCore().run(ASpec).failureCount

build.gradle

apply plugin: 'groovy'
apply plugin: 'java'

repositories {
    mavenLocal()
    mavenCentral()
}

dependencies {
    groovy 'org.codehaus.groovy:groovy-all:1.7.10'
    testCompile 'org.spockframework:spock-core:0.5-groovy-1.7'
}

specs.groovy

package foobar;

import spock.lang.*

class ASpec extends Specification {

    def "private static class#static method"() {
        expect:
            A.B.staticMethod() == 'static method'
    }

    def "private static class#instance method"() {
        expect:
            new A.B().instanceMethod() == 'instance method'
    }

    def "private class#instance method"() {
        expect:
            new A.C().instanceMethod() == 'instance method'
    }

}