fix(throttleTime): add back asDiagram specs

spec/operators/throttleTime-spec.ts

@@ -178,4 +178,32 @@ describe('Observable.prototype.throttleTime', () => {
     expectObservable(e1.throttleTime(50, rxTestScheduler)).toBe(expected);
     expectSubscriptions(e1.subscriptions).toBe(subs);
   });
+
+  describe('throttleTime(fn, { leading: true, trailing: true })', () => {
+    asDiagram('throttleTime(fn, { leading: true, trailing: true })')('should immediately emit the first value in each time window', () =>  {
+      const e1 =   hot('-a-xy-----b--x--cxxx---|');
+      const e1subs =   '^                      !';
+      const t =  time( '----|                  ');
+      const expected = '-a---y----b---x---x---x|';
+
+      const result = e1.throttleTime(t, rxTestScheduler, { leading: true, trailing: true });
+
+      expectObservable(result).toBe(expected);
+      expectSubscriptions(e1.subscriptions).toBe(e1subs);
+    });
+  });
+
+  describe('throttleTime(fn, { leading: false, trailing: true })', () => {
+    asDiagram('throttleTime(fn, { leading: false, trailing: true })')('should emit last given value in each time window', () =>  {
+      const e1 =   hot('-a-xy-----b--x--cxcd---|');
+      const e1subs =   '^                      !';
+      const t =  time( '----|                  ');
+      const expected = '-----y--------x---c---d|';
+
+      const result = e1.throttleTime(t, rxTestScheduler, { leading: false, trailing: true });
+
+      expectObservable(result).toBe(expected);
+      expectSubscriptions(e1.subscriptions).toBe(e1subs);
+    });
+  });
 });