eslint-plugin-jest/lib/rules/__tests__/prefer-spy-on.test.js

Eslint rules for Jest

'use strict';

const _require = require('eslint'),
      RuleTester = _require.RuleTester;

const rule = require('../prefer-spy-on');

const ruleTester = new RuleTester({
  parserOptions: {
    ecmaVersion: 6
  }
});
ruleTester.run('prefer-spy-on', rule, {
  valid: ['Date.now = () => 10', 'window.fetch = jest.fn', 'Date.now = fn()', 'obj.mock = jest.something()', 'const mock = jest.fn()', 'mock = jest.fn()', 'const mockObj = { mock: jest.fn() }', 'mockObj = { mock: jest.fn() }', 'window[`${name}`] = jest[`fn${expression}`]()'],
  invalid: [{
    code: 'obj.a = jest.fn(); const test = 10;',
    errors: [{
      messageId: 'useJestSpyOn',
      type: 'AssignmentExpression'
    }],
    output: "jest.spyOn(obj, 'a'); const test = 10;"
  }, {
    code: "Date['now'] = jest['fn']()",
    errors: [{
      messageId: 'useJestSpyOn',
      type: 'AssignmentExpression'
    }],
    output: "jest.spyOn(Date, 'now')"
  }, {
    code: 'window[`${name}`] = jest[`fn`]()',
    errors: [{
      messageId: 'useJestSpyOn',
      type: 'AssignmentExpression'
    }],
    output: 'jest.spyOn(window, `${name}`)'
  }, {
    code: "obj['prop' + 1] = jest['fn']()",
    errors: [{
      messageId: 'useJestSpyOn',
      type: 'AssignmentExpression'
    }],
    output: "jest.spyOn(obj, 'prop' + 1)"
  }, {
    code: 'obj.one.two = jest.fn(); const test = 10;',
    errors: [{
      messageId: 'useJestSpyOn',
      type: 'AssignmentExpression'
    }],
    output: "jest.spyOn(obj.one, 'two'); const test = 10;"
  }, {
    code: 'obj.a = jest.fn(() => 10)',
    errors: [{
      messageId: 'useJestSpyOn',
      type: 'AssignmentExpression'
    }],
    output: "jest.spyOn(obj, 'a').mockImplementation(() => 10)"
  }, {
    code: "obj.a.b = jest.fn(() => ({})).mockReturnValue('default').mockReturnValueOnce('first call'); test();",
    errors: [{
      messageId: 'useJestSpyOn',
      type: 'AssignmentExpression'
    }],
    output: "jest.spyOn(obj.a, 'b').mockImplementation(() => ({})).mockReturnValue('default').mockReturnValueOnce('first call'); test();"
  }, {
    code: 'window.fetch = jest.fn(() => ({})).one.two().three().four',
    errors: [{
      messageId: 'useJestSpyOn',
      type: 'AssignmentExpression'
    }],
    output: "jest.spyOn(window, 'fetch').mockImplementation(() => ({})).one.two().three().four"
  }]
});