如何JUnit测试两个List< E>包含相同顺序的相同元素? [英] How to JUnit test that two List<E> contain the same elements in the same order?

问题描述

我正在编写一个简单的 JUnit 测试MyObject类.

I am writing a simple JUnit test for the MyObject class.

可以从采用

A MyObject can be created from a static factory method that takes a varargs of String.

MyObject.ofComponents("Uno", "Dos", "Tres");

在MyObject存在期间的任何时间，客户端可以以

At any time during the existence of MyObject, clients can inspect the parameters it was created by in the form of a List<E>, through the .getComponents() method.

myObject.ofComponents(); // -> List<String>: { "Uno", "Dos", "Tres" }

换句话说，MyObject既记住并公开了使之成为现实的参数列表.有关此合同的更多详细信息:

In other words, a MyObject both remembers and exposes the list of parameters that brought it into existence. More details about this contract:

• getComponents的顺序与创建对象时选择的顺序相同
• 重复后续的

• The order of getComponents will be the same as the one chosen for object creation
• Duplicate subsequent String components are allowed and retained in order
• Behaviour on null is undefined (other code guarantees no null gets to the factory)
• There are no ways to alter the list of components after object instantiation

我正在编写一个简单的测试，该测试从

I am writing a simple test that creates a MyObject from a list of String and checks that it can return the same list via .getComponents(). I do this immediately but this is supposed to happen at a distance in a realistic code path.

这是我的尝试:

List<String> argumentComponents = Lists.newArrayList("One", "Two", "Three");
List<String> returnedComponents =
    MyObject.ofComponents(
        argumentComponents.toArray(new String[argumentComponents.size()]))
        .getComponents();
assertTrue(Iterables.elementsEqual(argumentComponents, returnedComponents));

---

问题

• 是 Google Guava Iterables.elementsEqual()最好的方法是，如果我在构建路径中有库，可以比较这两个列表?我一直在为此苦恼；我应该使用遍历

  ---

  Question

  • Is Google Guava Iterables.elementsEqual() the best way, provided I have the library in my build path, to compare those two lists? this is something I have been agonizing about; should I use this helper method which goes over an Iterable<E>.. check size and then iterate running .equals().. or any other of the methods that an Internet search suggests? what's the canonical way to compare lists for unit tests?
  • 方法测试是否合理设计?我不是 JUnit 的专家>！
  • .toArray()是转换 推荐答案

    我更喜欢使用Hamcrest，因为在出​​现故障的情况下它可以提供更好的输出

    I prefer using Hamcrest because it gives much better output in case of a failure

    Assert.assertThat(listUnderTest, 
           IsIterableContainingInOrder.contains(expectedList.toArray()));
    

    代替报告

    expected true, got false

    它将报告

    expected List containing "1, 2, 3, ..." got list containing "4, 6, 2, ..."

    IsIterableContainingInOrder.contain

    Hamcrest

    根据Javadoc:

    为Iterables创建一个匹配器，该匹配器在检查的Iterable上单次通过时会产生一系列项目，每个项目在逻辑上都等于指定项目中的相应项目.对于正匹配，所检查的可迭代项的长度必须与指定项目的数量相同

    Creates a matcher for Iterables that matches when a single pass over the examined Iterable yields a series of items, each logically equal to the corresponding item in the specified items. For a positive match, the examined iterable must be of the same length as the number of specified items

    因此listUnderTest必须具有相同数量的元素，并且每个元素必须按顺序匹配期望值.

    So the listUnderTest must have the same number of elements and each element must match the expected values in order.

    这篇关于如何JUnit测试两个List&lt; E&gt;包含相同顺序的相同元素?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！