Question

Jest的toEqual匹配器在检查相等性时会考虑空格。在测试中格式化期望值时，不可能以匹配包含换行符，制表符等的字符串的方式执行此操作。

Jest是否提供了一种在匹配时忽略空格的方法？

注意：我编辑了这个问题，使其更具通用性。

Answer 1

正如@Timo所说，这样做的唯一方法似乎是使用自定义匹配器。以下是基于Jest的toEqual匹配器将所有空格压缩到单个空间以便于阅读的内容。它将处理选项卡，换行符等。它将为您提供非常好的输出，如包含的Jest匹配器：

import { replace, map, equals } from 'ramda';
import { matcherHint, printReceived, printExpected } from 'jest-matcher-utils';
import diff from 'jest-diff';

const replaceWhitespace = replace(/\s+/g, ` `);
const compressWhitespace = map(replaceWhitespace);

const name = `toEqualWithCompressedWhitespace`;

export default (received, expected) => {
  const [
    receivedWithCompresssedWhitespace,
    expectedWithCompresssedWhitespace,
  ] = compressWhitespace([received, expected]);
  const pass = equals(
    receivedWithCompresssedWhitespace,
    expectedWithCompresssedWhitespace
  );
  const message = pass
    ? () =>
        `${matcherHint(`.not.${name}`)}\n\n` +
        `Uncompressed expected value:\n` +
        `  ${printExpected(expected)}\n` +
        `Expected value with compressed whitespace to not equal:\n` +
        `  ${printExpected(expectedWithCompresssedWhitespace)}\n` +
        `Uncompressed received value:\n` +
        `  ${printReceived(received)}\n` +
        `Received value with compressed whitespace:\n` +
        `  ${printReceived(receivedWithCompresssedWhitespace)}`
    : () => {
        const diffString = diff(
          expectedWithCompresssedWhitespace,
          receivedWithCompresssedWhitespace,
          {
            expand: this.expand,
          }
        );
        return (
          `${matcherHint(`.${name}`)}\n\n` +
          `Uncompressed expected value:\n` +
          `  ${printExpected(expected)}\n` +
          `Expected value with compressed whitespace to equal:\n` +
          `  ${printExpected(expectedWithCompresssedWhitespace)}\n` +
          `Uncompressed received value:\n` +
          `  ${printReceived(received)}\n` +
          `Received value with compressed whitespace:\n` +
          `  ${printReceived(receivedWithCompresssedWhitespace)}${
            diffString ? `\n\nDifference:\n\n${diffString}` : ``
          }`
        );
      };
  return {
    actual: received,
    expected,
    message,
    name,
    pass,
  };
};

要注册自定义匹配器，您需要使用jest.config.js字段将包含该文件的文件添加到setupTestFrameworkScriptFile：

 setupTestFrameworkScriptFile: `<rootDir>/path/to/customMatchers.js`,

Answer 2

据我所知，开箱即用的Jest无法实现这一目标。

然而，write your own reusable matcher using expect.extend非常简单。从两个字符串中删除所有空格，例如通过str.replace(/\s/g, '')，比较字符串。

Answer 3

虽然这不是直接答案，但您也可以这样做：

mockedFunction.mock.calls[0] // To get array of arguments

// or 

mockedFunction.mock.calls[0][0] // to get first argument and so on

然后与相等进行比较。

对于忽视空白的字符串的Jest Equality Matcher

3 个答案: