Hamcrest 的 hasItems、contains 和 containsInAnyOrder 有何不同？

Question

Hamcrest 提供了许多匹配器来断言集合的内容。所有这些案例都通过了：

Collection<String> c = ImmutableList.of("one", "two", "three");
assertThat(c, hasItems("one", "two", "three");
assertThat(c, contains("one", "two", "three");
assertThat(c, containsInAnyOrder("one", "two", "three");

hasItems、contains 和 containsInAnyOrder 有何不同？

Answer 1

hasItems checks:

consecutive passes over the examined Iterable yield at least one item that is equal to the corresponding item from the specified items.

也就是说，它确保集合包含至少这些项目，任何顺序。所以，

assertThat(c, hasItems("one", "two"));

也会通过，多余的项目将被忽略。并且：

assertThat(c, hasItems("three", "two", "one"));

也会通过。

contains checks:

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.

因此它确保该集合包含恰好这些项目：

assertThat(c, contains("one", "two")); // Fails

这会失败，因为剩余的 "three" 不匹配。

assertThat(c, contains("three", "two", "one")); // Fails

这失败了，因为相应的项目不匹配。

另一个相关的匹配器，containsInAnyOrder，checks 正是这些项目存在，但顺序不限：

Creates an order agnostic matcher for Iterables that matches when a single pass over the examined Iterable yields a series of items, each logically equal to one item anywhere in the specified items.

缺少项目的测试失败：

assertThat(c, containsInAnyOrder("one", "two")); // Fails

但不同顺序的所有项目都会通过：

assertThat(c, containsInAnyOrder("three", "two", "one"));

Hamcrest 的 hasItems、contains 和 containsInAnyOrder 有何不同？

How do Hamcrest's hasItems, contains and containsInAnyOrder differ?

hamcrest