fix(VirtualAction): Block rescheduled VirtualActions from executing t…

…heir scheduled work.

VirtualActions are immutable so they can be inspected by the TestScheduler. In order to mirror

rescheduled stateful Actions, rescheduled VirtualActions shouldn't execute if they've been

rescheduled before execution.

src/scheduler/VirtualTimeScheduler.ts

@@ -46,6 +46,8 @@ export class VirtualTimeScheduler extends AsyncScheduler {
  */
 export class VirtualAction<T> extends AsyncAction<T> {
 
+  protected active: boolean = true;
+
   constructor(protected scheduler: VirtualTimeScheduler,
               protected work: (this: VirtualAction<T>, state?: T) => void,
               protected index: number = scheduler.index += 1) {
@@ -54,8 +56,11 @@ export class VirtualAction<T> extends AsyncAction<T> {
   }
 
   public schedule(state?: T, delay: number = 0): Subscription {
-    return !this.id ?
-      super.schedule(state, delay) : (
+    if (!this.id) {
+      return super.schedule(state, delay);
+    }
+    this.active = false;
+    return (
       // If an action is rescheduled, we save allocations by mutating its state,
       // pushing it to the end of the scheduler queue, and recycling the action.
       // But since the VirtualTimeScheduler is used for testing, VirtualActions
@@ -77,6 +82,12 @@ export class VirtualAction<T> extends AsyncAction<T> {
     return undefined;
   }
 
+  protected _execute(state: T, delay: number): any {
+    if (this.active === true) {
+      return super._execute(state, delay);
+    }
+  }
+
   public static sortActions<T>(a: VirtualAction<T>, b: VirtualAction<T>) {
     if (a.delay === b.delay) {
       if (a.index === b.index) {