September 2022
Intermediate to advanced
585 pages
8h 17m
Chinese
Content preview from JavaScript 经典实例：第三版
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282
｜
第
10
章
at factorialize (factorialize.js:6:11)
at Object.<anonymous> (factorialize.test.js:17:12)
Test Suites: 1 failed, 1 total
Tests: 1 failed, 4 passed, 5 total
Snapshots: 0 total
Time: 2.833 s
Ran all test suites.
目前，我们见到的测试都使用
toBe()
匹配器函数检查具体的值。不过，
Jest
与所
有测试框架一样，也支持使用其他类型的规则。例如，可以检查一个数字是否落在
指定的范围内，可以检查文本是否匹配特定的模式，还可以检查一个值是否不是
null
。表
10-2
列出了可以与
expect()
搭配使用的部分常用匹配器函数。完整的列
表参见
Jest expect()
方法的文档（
https://oreil.ly/hnbiy
）。
表
10
-
2
：Jest 匹配器函数
函数
说明
arrayContaining()
在数组中搜索指定的值
not()
逆转条件
。
例如
，
当值不是
5
时
，
expect(...).not.toBe(5)
可以通过
stringContaining()
在字符串中搜索子串
stringMatching()
尝试使用正则表达式匹配字符串
toBe()
测试标准的
JavaScript
相等性
，
跟使用
==
运算符一样
toBeCloseTo()
测试两个数字是否相等或非常接近
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