sonukapoor · Dec 2, 2019 · Sep 14, 2020
diff --git a/aio/content/examples/observables-in-angular/src/main.ts b/aio/content/examples/observables-in-angular/src/main.ts
@@ -1,3 +1,4 @@
+// TODO: Add unit tests for this file.
 // tslint:disable: no-output-native
 // #docregion
 import { Component, Output, OnInit, EventEmitter, NgModule } from '@angular/core';

diff --git a/aio/content/examples/observables/example-config.json b/aio/content/examples/observables/example-config.json
@@ -2,7 +2,11 @@
   "tests": [
     {
       "cmd": "yarn",
-      "args": [ "tsc", "--project", "./tsconfig.app.json" ]
+      "args": ["tsc", "--project", "tsconfig.spec.json", "--module", "commonjs"]
+    },
+    {
+      "cmd": "yarn",
+      "args": ["jasmine", "out-tsc/**/*.spec.js"]
     }
   ]
 }
diff --git a/aio/content/examples/observables/src/creating.spec.ts b/aio/content/examples/observables/src/creating.spec.ts
@@ -0,0 +1,55 @@
+import { docRegionFromEvent, docRegionSubscriber } from './creating';
+
+describe('observables', () => {
+  it('should create an observable using the constructor', () => {
+    const console = {log: jasmine.createSpy('log')};
+    docRegionSubscriber(console);
+    expect(console.log).toHaveBeenCalledTimes(4);
+    expect(console.log.calls.allArgs()).toEqual([
+      [1],
+      [2],
+      [3],
+      ['Finished sequence'],
+    ]);
+  });
+
+  it('should listen to input changes', () => {
+    let triggerInputChange;
+    const input = {
+      value: 'Test',
+      addEventListener: jasmine
+        .createSpy('addEvent')
+        .and.callFake((eventName: string, cb: (e) => void) => {
+          if (eventName === 'keydown') {
+            triggerInputChange = cb;
+          }
+        }),
+      removeEventListener: jasmine.createSpy('removeEventListener'),
+    };
+
+    const document = { getElementById: () => input };
+    docRegionFromEvent(document);
+    triggerInputChange({keyCode: 65});
+    expect(input.value).toBe('Test');
+
+    triggerInputChange({keyCode: 27});
+    expect(input.value).toBe('');
+  });
+
+  it('should call removeEventListener when unsubscribing', (doneFn: DoneFn) => {
+    const input = {
+      addEventListener: jasmine.createSpy('addEvent'),
+      removeEventListener: jasmine
+        .createSpy('removeEvent')
+        .and.callFake((eventName: string, cb: (e) => void) => {
+          if (eventName === 'keydown') {
+            doneFn();
+          }
+        })
+    };
+
+    const document = { getElementById: () => input };
+    const subscription = docRegionFromEvent(document);
+    subscription.unsubscribe();
+  });
+});
diff --git a/aio/content/examples/observables/src/creating.ts b/aio/content/examples/observables/src/creating.ts
@@ -1,38 +1,39 @@
+// #docplaster
 
 import { Observable } from 'rxjs';
 
-// #docregion subscriber
-
-// This function runs when subscribe() is called
-function sequenceSubscriber(observer) {
-  // synchronously deliver 1, 2, and 3, then complete
-  observer.next(1);
-  observer.next(2);
-  observer.next(3);
-  observer.complete();
+export function docRegionSubscriber(console) {
+  // #docregion subscriber
+  // This function runs when subscribe() is called
+  function sequenceSubscriber(observer) {
+    // synchronously deliver 1, 2, and 3, then complete
+    observer.next(1);
+    observer.next(2);
+    observer.next(3);
+    observer.complete();
+
+    // unsubscribe function doesn't need to do anything in this
+    // because values are delivered synchronously
+    return {unsubscribe() {}};
+  }
+
+  // Create a new Observable that will deliver the above sequence
+  const sequence = new Observable(sequenceSubscriber);
+
+  // execute the Observable and print the result of each notification
+  sequence.subscribe({
+    next(num) { console.log(num); },
+    complete() { console.log('Finished sequence'); }
+  });
 
-  // unsubscribe function doesn't need to do anything in this
-  // because values are delivered synchronously
-  return {unsubscribe() {}};
+  // Logs:
+  // 1
+  // 2
+  // 3
+  // Finished sequence
+  // #enddocregion subscriber
 }
 
-// Create a new Observable that will deliver the above sequence
-const sequence = new Observable(sequenceSubscriber);
-
-// execute the Observable and print the result of each notification
-sequence.subscribe({
-  next(num) { console.log(num); },
-  complete() { console.log('Finished sequence'); }
-});
-
-// Logs:
-// 1
-// 2
-// 3
-// Finished sequence
-
-// #enddocregion subscriber
-
 // #docregion fromevent
 
 function fromEvent(target, eventName) {
@@ -51,16 +52,18 @@ function fromEvent(target, eventName) {
 
 // #enddocregion fromevent
 
-// #docregion fromevent_use
+export function docRegionFromEvent(document) {
+  // #docregion fromevent_use
 
-const ESC_KEY = 27;
-const nameInput = document.getElementById('name') as HTMLInputElement;
+  const ESC_KEY = 27;
+  const nameInput = document.getElementById('name') as HTMLInputElement;
 
-const subscription = fromEvent(nameInput, 'keydown')
-  .subscribe((e: KeyboardEvent) => {
+  const subscription = fromEvent(nameInput, 'keydown').subscribe((e: KeyboardEvent) => {
     if (e.keyCode === ESC_KEY) {
       nameInput.value = '';
     }
   });
+  // #enddocregion fromevent_use
+  return subscription;
+}
 
-// #enddocregion fromevent_use
diff --git a/aio/content/examples/observables/src/geolocation.ts b/aio/content/examples/observables/src/geolocation.ts
@@ -1,5 +1,5 @@
+// TODO: Add unit tests for this file.
 import { Observable } from 'rxjs';
-
 // #docregion
 
 // Create an Observable that will start listening to geolocation updates

diff --git a/aio/content/examples/observables/src/multicasting.spec.ts b/aio/content/examples/observables/src/multicasting.spec.ts
@@ -0,0 +1,48 @@
+import { docRegionDelaySequence, docRegionMulticastSequence } from './multicasting';
+
+describe('multicasting', () => {
+  let console;
+  beforeEach(() => {
+    jasmine.clock().install();
+    console = {log: jasmine.createSpy('log')};
+  });
+
+  afterEach(() => {
+    jasmine.clock().uninstall();
+  });
+
+  it('should create an observable and emit in sequence', () => {
+    docRegionDelaySequence(console);
+    jasmine.clock().tick(10000);
+    expect(console.log).toHaveBeenCalledTimes(12);
+    expect(console.log.calls.allArgs()).toEqual([
+      [1],
+      ['1st subscribe: 1'],
+      ['2nd subscribe: 1'],
+      [2],
+      ['1st subscribe: 2'],
+      ['2nd subscribe: 2'],
+      [3],
+      ['Finished sequence'],
+      ['1st subscribe: 3'],
+      ['1st sequence finished.'],
+      ['2nd subscribe: 3'],
+      ['2nd sequence finished.']
+    ]);
+  });
+
+  it('should create an observable and multicast the emissions', () => {
+    docRegionMulticastSequence(console);
+    jasmine.clock().tick(10000);
+    expect(console.log).toHaveBeenCalledTimes(7);
+    expect(console.log.calls.allArgs()).toEqual([
+      ['1st subscribe: 1'],
+      ['1st subscribe: 2'],
+      ['2nd subscribe: 2'],
+      ['1st subscribe: 3'],
+      ['2nd subscribe: 3'],
+      ['1st sequence finished.'],
+      ['2nd sequence finished.']
+    ]);
+  });
+});