检查 Hamcrest 中的列表是否为空 [英] Checking that a List is not empty in Hamcrest

问题描述

我想知道是否有人知道使用 assertThat() 和 Matchers 来检查 List 是否为空的方法?

I was wondering if anyone knew of a way to check if a List is empty using assertThat() and Matchers?

我认为最好的方法就是使用 JUnit:

Best way I could see just use JUnit:

assertFalse(list.isEmpty());

但我希望在 Hamcrest 有某种方法可以做到这一点.

But I was hoping that there was some way to do this in Hamcrest.

推荐答案

好吧

assertThat(list.isEmpty(), is(false));

...但我猜这不是你的意思:)

... but I'm guessing that's not quite what you meant :)

或者:

assertThat((Collection)list, is(not(empty())));

empty() 是 Matchers 类中的一个静态变量.请注意需要将 list 转换为 Collection，这要归功于 Hamcrest 1.2 的古怪泛型.

empty() is a static in the Matchers class. Note the need to cast the list to Collection, thanks to Hamcrest 1.2's wonky generics.

以下导入可以与 hamcrest 1.3 一起使用

The following imports can be used with hamcrest 1.3

import static org.hamcrest.Matchers.empty;
import static org.hamcrest.core.Is.is;
import static org.hamcrest.core.IsNot.*;

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