Function patchMocha

packages/zone.js/lib/mocha/mocha.ts:13–192

(Zone: ZoneType)

('use strict');

export function patchMocha(Zone: ZoneType): void {
  Zone.__load_patch('mocha', (global: any, Zone: ZoneType) => {
    const Mocha = global.Mocha;

    if (typeof Mocha === 'undefined') {
      // return if Mocha is not available, because now zone-testing
      // will load mocha patch with jasmine/jest patch
      return;
    }

    if (typeof Zone === 'undefined') {
      throw new Error('Missing Zone.js');
    }

    const ProxyZoneSpec = (Zone as any)['ProxyZoneSpec'];
    const SyncTestZoneSpec = (Zone as any)['SyncTestZoneSpec'];

    if (!ProxyZoneSpec) {
      throw new Error('Missing ProxyZoneSpec');
    }

    if (Mocha['__zone_patch__']) {
      throw new Error('"Mocha" has already been patched with "Zone".');
    }

    Mocha['__zone_patch__'] = true;

    const rootZone = Zone.current;
    const syncZone = rootZone.fork(new SyncTestZoneSpec('Mocha.describe'));
    let testZone: Zone | null = null;
    const suiteZone = rootZone.fork(new ProxyZoneSpec());

    const mochaOriginal = {
      after: global.after,
      afterEach: global.afterEach,
      before: global.before,
      beforeEach: global.beforeEach,
      describe: global.describe,
      it: global.it,
    };

    function modifyArguments(args: IArguments, syncTest: Function, asyncTest?: Function): any[] {
      for (let i = 0; i < args.length; i++) {
        let arg = args[i];
        if (typeof arg === 'function') {
          // The `done` callback is only passed through if the function expects at
          // least one argument.
          // Note we have to make a function with correct number of arguments,
          // otherwise mocha will
          // think that all functions are sync or async.
          args[i] = arg.length === 0 ? syncTest(arg) : asyncTest!(arg);
          // Mocha uses toString to view the test body in the result list, make sure we return the
          // correct function body
          args[i].toString = function () {
            return arg.toString();
          };
        }
      }