Jest

  • Matchers 匹配器
  • IDE
  • Linting
  • Runners
  • Reporters
  • Results Processors
  • Environments
  • Snapshot
  • Migration
  • Library extensions
  • Mocks
  • Watch Plugins
  • Processor
  • Presets
  • test 方法:Jest 封装的测试方法,一般填写两个参数,测试用例描述和测试方法
  • expect 方法:预期方法,就是你调用了什么方法,传递了什么参数,得到的预期是什么

单元测试和集成测试

  • 单元测试:英文是(unit testing) 单,是指对软件中的最小可测试单元进行检查和验证。前端所说的单元测试就是对一个模块进行测试。也就是说前端测试的时候,你测试的东西一定是一个模块。
  • 集成测试:也叫组装测试或者联合测试。在单元测试的基础上,将所有模块按照涉及要求组装成为子系统或系统,进行集成测试。

匹配器

Jest 匹配器列表

  • 普通比较
    • toBe
    • toEuqual

异步代码

Asynchronous Code

  • Callback
  • Promises

设置和卸载

钩子:

  • 很多测试用例中重复设置
    • beforeEach
    • afterEach
  • 一次设置
    • beforeAll
    • afterAll

模拟函数

指引

  • 快照测试 Snapshot
  • 定时器函数

命令行工具

Jest CLI Options

  • 测试环境
    • Node
    • jsdom(browser-like)
  • 编译代码
    • v8
    • babel

配置文件

Configuring Jest

babel-jest

// For a detailed explanation regarding each configuration property, visit:
// https://jestjs.io/docs/en/configuration.html
module.exports = {
// All imported modules in your tests should be mocked automatically
// automock: false,
// Stop running tests after `n` failures
// bail: 0,
// The directory where Jest should store its cached dependency information
// cacheDirectory: "/private/var/folders/pv/cf9vq9sj6y32mtgw93mxjjfr0000gn/T/jest_dx",
// Automatically clear mock calls and instances between every test
clearMocks: true,
// Indicates whether the coverage information should be collected while executing the test
// collectCoverage: false,
// An array of glob patterns indicating a set of files for which coverage information should be collected
// collectCoverageFrom: undefined,
// The directory where Jest should output its coverage files
coverageDirectory: 'coverage',
// An array of regexp pattern strings used to skip coverage collection
// coveragePathIgnorePatterns: [
// "/node_modules/"
// ],
// Indicates which provider should be used to instrument code for coverage
// coverageProvider: "babel",
// A list of reporter names that Jest uses when writing coverage reports
// coverageReporters: [
// "json",
// "text",
// "lcov",
// "clover"
// ],
// An object that configures minimum threshold enforcement for coverage results
// coverageThreshold: undefined,
// A path to a custom dependency extractor
// dependencyExtractor: undefined,
// Make calling deprecated APIs throw helpful error messages
// errorOnDeprecated: false,
// Force coverage collection from ignored files using an array of glob patterns
// forceCoverageMatch: [],
// A path to a module which exports an async function that is triggered once before all test suites
// globalSetup: undefined,
// A path to a module which exports an async function that is triggered once after all test suites
// globalTeardown: undefined,
// A set of global variables that need to be available in all test environments
// globals: {},
// The maximum amount of workers used to run your tests. Can be specified as % or a number. E.g. maxWorkers: 10% will use 10% of your CPU amount + 1 as the maximum worker number. maxWorkers: 2 will use a maximum of 2 workers.
// maxWorkers: "50%",
// An array of directory names to be searched recursively up from the requiring module's location
// moduleDirectories: [
// "node_modules"
// ],
// An array of file extensions your modules use
// moduleFileExtensions: [
// "js",
// "json",
// "jsx",
// "ts",
// "tsx",
// "node"
// ],
// A map from regular expressions to module names or to arrays of module names that allow to stub out resources with a single module
// moduleNameMapper: {},
// An array of regexp pattern strings, matched against all module paths before considered 'visible' to the module loader
// modulePathIgnorePatterns: [],
// Activates notifications for test results
// notify: false,
// An enum that specifies notification mode. Requires { notify: true }
// notifyMode: "failure-change",
// A preset that is used as a base for Jest's configuration
// preset: undefined,
// Run tests from one or more projects
// projects: undefined,
// Use this configuration option to add custom reporters to Jest
// reporters: undefined,
// Automatically reset mock state between every test
// resetMocks: false,
// Reset the module registry before running each individual test
// resetModules: false,
// A path to a custom resolver
// resolver: undefined,
// Automatically restore mock state between every test
// restoreMocks: false,
// The root directory that Jest should scan for tests and modules within
// rootDir: undefined,
// A list of paths to directories that Jest should use to search for files in
// roots: [
// "<rootDir>"
// ],
// Allows you to use a custom runner instead of Jest's default test runner
// runner: "jest-runner",
// The paths to modules that run some code to configure or set up the testing environment before each test
// setupFiles: [],
// A list of paths to modules that run some code to configure or set up the testing framework before each test
// setupFilesAfterEnv: [],
// The number of seconds after which a test is considered as slow and reported as such in the results.
// slowTestThreshold: 5,
// A list of paths to snapshot serializer modules Jest should use for snapshot testing
// snapshotSerializers: [],
// The test environment that will be used for testing
// testEnvironment: "jest-environment-jsdom",
// Options that will be passed to the testEnvironment
// testEnvironmentOptions: {},
// Adds a location field to test results
// testLocationInResults: false,
// The glob patterns Jest uses to detect test files
// testMatch: [
// "**/__tests__/**/*.[jt]s?(x)",
// "**/?(*.)+(spec|test).[tj]s?(x)"
// ],
// An array of regexp pattern strings that are matched against all test paths, matched tests are skipped
// testPathIgnorePatterns: [
// "/node_modules/"
// ],
// The regexp pattern or array of patterns that Jest uses to detect test files
// testRegex: [],
// This option allows the use of a custom results processor
// testResultsProcessor: undefined,
// This option allows use of a custom test runner
// testRunner: "jasmine2",
// This option sets the URL for the jsdom environment. It is reflected in properties such as location.href
// testURL: "http://localhost",
// Setting this value to "fake" allows the use of fake timers for functions such as "setTimeout"
// timers: "real",
// A map from regular expressions to paths to transformers
// transform: undefined,
// An array of regexp pattern strings that are matched against all source file paths, matched files will skip transformation
// transformIgnorePatterns: [
// "/node_modules/"
// ],
// An array of regexp pattern strings that are matched against all modules before the module loader will automatically return a mock for them
// unmockedModulePathPatterns: undefined,
// Indicates whether each individual test should be reported during the run
// verbose: undefined,
// An array of regexp patterns that are matched against all source file paths before re-running tests in watch mode
// watchPathIgnorePatterns: [],
// Whether to use watchman for file crawling
// watchman: true,
};