如果依赖注入不可行，我如何从单元测试的实现中解耦实例化？

// 接口或抽象类
public interface ObjectFactory {
    Object createObject();
}

// 具体工厂类
public class ConcreteObjectFactory implements ObjectFactory {
    public Object createObject() {
        // 实例化对象的逻辑
        return new Object();
    }
}

// 模拟工厂类
public class MockObjectFactory implements ObjectFactory {
    public Object createObject() {
        // 返回特定的对象实例，用于测试
        return new MockObject();
    }
}

// 测试类
public class UnitTest {
    private ObjectFactory factory;

    public UnitTest(ObjectFactory factory) {
        this.factory = factory;
    }

    public void test() {
        Object obj = factory.createObject();
        // 进行测试
    }
}

// 使用示例
public class Main {
    public static void main(String[] args) {
        // 使用实际的工厂类
        ObjectFactory factory = new ConcreteObjectFactory();
        UnitTest test = new UnitTest(factory);
        test.test();

        // 使用模拟的工厂类
        ObjectFactory mockFactory = new MockObjectFactory();
        UnitTest mockTest = new UnitTest(mockFactory);
        mockTest.test();
    }
}