Creating spec reproducing situation where 'idle' is called but 'willI…

…dle' is not

src/strongbus_spec.ts

@@ -641,6 +641,16 @@ describe('Strongbus.Bus', () => {
         expect(onActive).toHaveBeenCalledTimes(1);
       });
 
+      fit('handles unsubscribes fired from hooks', async () => {
+        const sub1 = bus.on('foo', () => {});
+        const sub2 = bus.on('foo', () => {});
+        bus.hook('willRemoveListener', () => sub2());
+
+        sub1();
+        expect(onWillIdle).toHaveBeenCalledTimes(1);
+        expect(onIdle).toHaveBeenCalledTimes(1);
+      });
+
       it('raises "idle" events independently of delegates', () => {
         const foosub = bus.on('foo', onTestEvent);
         const fooSub2 = delegate.on('foo', onTestEvent);