Friday, August 03, 2018

jasminejs tests with es2015 modules

Running jasminejs tests of javascript modules in a browser is straight forward, but requires small adjustments, since a module loads asynchronously, while jasmine's default runtime assumes code loads synchronously. The approach I take is the same as the one used to test requirejs AMD modules:

  • customize jasmine boot, so that it does not automatically launch test execution on page load
  • write a testMain.js script that imports all the spec's for your test suite, then launches jasmine's test execution

For example, this is the root test suite (testMain.ts) for the @littleware/little-elements module:

import './test/spec/utilSpec.js';
import './arrivalPie/spec/arrivalPieSpec.js';
import './styleGuide/spec/styleGuideSpec.js';
import {startTest} from './test/util.js';

startTest();

The startTest() function is a little wrapper that detects whether karmajs is the test runtime, since the test bootstrap process is a little different in that scenario. The karmajs config file should also annotate javascript module files with a module type. For example, here is an excerpt from little-element's karma.conf.js:

    files: [
      'lib/test/karmaAdapter.js',
      { pattern: 'lib/arrivalPie/**/*.js', type: 'module', included: false },
      { pattern: 'lib/styleGuide/**/*.js', type: 'module', included: false },
      { pattern: 'lib/test/**/*.js', type: 'module', included: false },
      { pattern: 'lib/testMain.js', type: 'module', included: true },
      { pattern: 'node_modules/lit-html/*.js', type: 'module', included: false }
    ],

Feel free to import the @littleware/little-elements module into your project if it will be helpful!

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