我们是否应该对接口中的默认方法进行单元测试（Java 8）？ [英] Should we do unit testing for default methods in interfaces (Java 8)?

问题描述

我对Java 8中引入的接口中的默认方法实现感到有点困惑。我想知道是否应该专门为接口及其实现的方法编写JUnit测试。我试图谷歌它，但我找不到一些指导方针。请指教。

I feel a bit confused about the default methods implementations in interfaces introduced in Java 8. I was wondering if we should write JUnit tests specifically for an interface and its implemented methods. I tried to google it, but I couldn't find some guidelines. Please advise.

推荐答案

这取决于方法的复杂程度。如果代码很简单，则没有必要，例如：

Its depends on the method complexity. It is not really necessary if the code is trivial, for example:

public interface MyInterface {
    ObjectProperty<String> ageProperty();
    default String getAge() {
        return ageProperty().getValue();
    }
}

如果代码更复杂，那么你应该写单元测试。例如，此默认方法来自 Comparator ：

If the code is more complex, then you should write a unit test. For example, this default method from Comparator:

public interface Comparator<T> {
    ...
    default Comparator<T> thenComparing(Comparator<? super T> other) {
        Objects.requireNonNull(other);
        return (Comparator<T> & Serializable) (c1, c2) -> {
            int res = compare(c1, c2);
            return (res != 0) ? res : other.compare(c1, c2);
        };
    }
    ...
}

如何测试它？

从接口测试默认方法与测试抽象类相同。

Testing a default method from an interface is the same as testing an abstract class.

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