feat(VirtualObserver): implements VirtualObserver

Author: kwonoj

src/VirtualObserver.ts

@@ -0,0 +1,30 @@
+import * as Rx from 'rxjs';
+import { Scheduler } from 'rxjs/Scheduler';
+import { TestMessageValue } from './TestMessageValue';
+
+/**
+ * Observer interface allows to record emitted values in form of TestMessageValue for inspection
+ *
+ */
+export interface VirtualObserver<T = string> extends Rx.Observer<T> {
+  readonly messages: Readonly<Array<TestMessageValue<T>>>;
+}
+
+export class BaseVirtualObserver<T = string> implements VirtualObserver<T> {
+  public readonly messages: Readonly<Array<TestMessageValue<T>>> = [];
+
+  constructor(private readonly scheduler: Scheduler) {
+  }
+
+  next(value: T): void {
+    this.messages.push(new TestMessageValue(this.scheduler.now(), Rx.Notification.createNext(value)));
+  }
+
+  error(value: any): void {
+    this.messages.push(new TestMessageValue<any>(this.scheduler.now(), Rx.Notification.createError(value)));
+  }
+
+  complete(): void {
+    this.messages.push(new TestMessageValue(this.scheduler.now(), Rx.Notification.createComplete()));
+  }
+}