Description for mocking external components may be wrong

[azizk]

Description

Steps to Reproduce

The README describes how to mock external components, but in my case for lightning/primitiveIcon it doesn't work. It works if you provide the full path to the js file in the mapped module path in jest.config.js.

// The test function is not really relevant

<!-- /force-app/stdlib/jest-mocks/lightning/primitiveIcon.html -->
<template></template>

// /force-app/stdlib/jest-mocks/lightning/primitiveIcon.js
import { api, LightningElement } from "lwc";

export default class PrimitiveIcon extends LightningElement {
  @api iconName;
  @api size;
  @api svgClass;
  @api variant;
}

const { jestConfig } = require("@salesforce/sfdx-lwc-jest/config");
module.exports = {
  ...jestConfig,
  modulePathIgnorePatterns: ["<rootDir>/.localdevserver"],
  moduleNameMapper: {
    "^lightning/(primitiveIcon)$":
      "<rootDir>/force-app/stdlib/jest-mocks/lightning/$1"
  },
  collectCoverage: true,
  coverageReporters: ["cobertura", "text"]
};

sfdx-lwc-jest --coverage

Expected Results

Should not throw a configuration error.

Actual Results

  ● Test suite failed to run

    Configuration error:
    
    Could not locate module lightning/primitiveIcon mapped as:
    /home/work/src/project/force-app/stdlib/jest-mocks/lightning/$1.
    
    Please check your configuration for these entries:
    {
      "moduleNameMapper": {
        "/^lightning\/(primitiveIcon)$/": "/home/work/src/project/force-app/stdlib/jest-mocks/lightning/$1"
      },
      "resolver": /home/work/src/project/node_modules/@salesforce/sfdx-lwc-jest/src/resolver.js
    }

      at createNoMappedModuleFoundError (node_modules/jest-resolve/build/resolver.js:900:17)
      at Object.<anonymous> (force-app/stdlib/lwc/button/button.html.compiled:5:1)

Version

• @salesforce/sfdx-lwc-jest: 1.1.2

Possible Solution

The solution is to add the js file name to the mapped module path:

module.exports = {
  ...,
  moduleNameMapper: {
    "^lightning/(primitiveIcon)$":
      "<rootDir>/force-app/stdlib/jest-mocks/lightning/$1/$1.js"
  }
};