To reproduce the issue, run ng test.
You should receive the following error:
TypeError:: Cannot read property 'subscribe' of undefined
at http://localhost:9876/_karma_webpack_/node_modules/@angular/cdk/__ivy_ngcc__/fesm2015/observers.js:151:58
at ZoneDelegate.invoke (http://localhost:9876/_karma_webpack_/node_modules/zone.js/dist/zone-evergreen.js:364:1)
at ProxyZoneSpec.push.QpwO.ProxyZoneSpec.onInvoke (http://localhost:9876/_karma_webpack_/node_modules/zone.js/dist/zone-testing.js:292:1)
at ZoneDelegate.invoke (http://localhost:9876/_karma_webpack_/node_modules/zone.js/dist/zone-evergreen.js:363:1)
at Zone.run (http://localhost:9876/_karma_webpack_/node_modules/zone.js/dist/zone-evergreen.js:123:1)
at NgZone.runOutsideAngular (http://localhost:9876/_karma_webpack_/node_modules/@angular/core/__ivy_ngcc__/fesm2015/core.js:27422:1)
at CdkObserveContent._subscribe (http://localhost:9876/_karma_webpack_/node_modules/@angular/cdk/__ivy_ngcc__/fesm2015/observers.js:149:1)
at CdkObserveContent.ngAfterContentInit (http://localhost:9876/_karma_webpack_/node_modules/@angular/cdk/__ivy_ngcc__/fesm2015/observers.js:136:1)
at callHook (http://localhost:9876/_karma_webpack_/node_modules/@angular/core/__ivy_ngcc__/fesm2015/core.js:3281:1)
at callHooks (http://localhost:9876/_karma_webpack_/node_modules/@angular/core/__ivy_ngcc__/fesm2015/core.js:3251:1)Run ng serve for a dev server. Navigate to http://localhost:4200/. The app will automatically reload if you change any of the source files.
Run ng generate component component-name to generate a new component. You can also use ng generate directive|pipe|service|class|guard|interface|enum|module.
Run ng build to build the project. The build artifacts will be stored in the dist/ directory. Use the --prod flag for a production build.
Run ng test to execute the unit tests via Karma.
Run ng e2e to execute the end-to-end tests via Protractor.
To get more help on the Angular CLI use ng help or go check out the Angular CLI README.