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JUnitassertEquals() 对于两个对象失败

发布于 2024-11-09 03:58:03 字数 134 浏览 0 评论 0原文

我创建了一个类并重写了 equals() 方法。当我使用assertTrue(obj1.equals(obj2))时，它会通过测试；但是，assertEquals(obj1, obj2) 将无法通过测试。有人可以告诉一下原因吗？

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浅语花开 2024-11-16 03:58:03

我的猜测是，您实际上并没有覆盖 equals - 您已经重载了它。使用 @Override 注释可以在编译时找到此类内容。

换句话说，我怀疑您已经：

public boolean equals(MyClass other)

您应该在哪里：

@Override // Force the compiler to check I'm really overriding something
public boolean equals(Object other)

在您的工作断言中，您无疑将重载方法调用为 obj1 和 obj2< 的编译时类型/code> 都是 MyClass （或者你的类的名称）。 JUnit 的 assertEquals 只会调用 equals(Object)，因为它不知道更多。

My guess is that you haven't actually overridden equals - that you've overloaded it instead. Use the @Override annotation to find this sort of thing out at compile time.

In other words, I suspect you've got:

public boolean equals(MyClass other)

where you should have:

@Override // Force the compiler to check I'm really overriding something
public boolean equals(Object other)

In your working assertion, you were no doubt calling the overloaded method as the compile-time type of obj1 and obj2 were both MyClass (or whatever your class is called). JUnit's assertEquals will only call equals(Object) as it doesn't know any better.

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执妄 2024-11-16 03:58:03

这是 assertEquals 的代码（来自 Github)：

static public void assertEquals(String message, Object expected,
        Object actual) {
    if (expected == null && actual == null)
        return;
    if (expected != null && isEquals(expected, actual))
        return;
    else if (expected instanceof String && actual instanceof String) {
        String cleanMessage= message == null ? "" : message;
        throw new ComparisonFailure(cleanMessage, (String) expected,
                (String) actual);
    } else
        failNotEquals(message, expected, actual);
}

private static boolean isEquals(Object expected, Object actual) {
    return expected.equals(actual);
}

我只能想到一种情况，其行为如您所描述的方式 - 如果您的 equals 方法不处理与 null 的比较 值正确。

Here is the code for assertEquals (from Github):

static public void assertEquals(String message, Object expected,
        Object actual) {
    if (expected == null && actual == null)
        return;
    if (expected != null && isEquals(expected, actual))
        return;
    else if (expected instanceof String && actual instanceof String) {
        String cleanMessage= message == null ? "" : message;
        throw new ComparisonFailure(cleanMessage, (String) expected,
                (String) actual);
    } else
        failNotEquals(message, expected, actual);
}

private static boolean isEquals(Object expected, Object actual) {
    return expected.equals(actual);
}

I can think of only one case where this behaves the way you described - if your equals method is not handling comparisons to null values correctly.

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