chore(afs): extend test coverage to multple snapshot listeners

Author: jamesdaniels

src/firestore/collection/collection.spec.ts

@@ -92,8 +92,7 @@ describe('AngularFirestoreCollection', () => {
           expect(data.length).toEqual(ITEMS);
           pricefilter$.next(-1);
         }
-        // on the second round, make sure the array is still the same
-        // length but the updated item is now modified
+        // on the second round, we should have filtered out everything
         if(count === 2) {
           expect(data.length).toEqual(0);
           sub.unsubscribe();
@@ -193,6 +192,35 @@ describe('AngularFirestoreCollection', () => {
       delayAdd(stocks, nextId, { price: 2 });
     });
 
+    it('should be able to filter snapshotChanges() types - added/modified', async (done) => {
+      const ITEMS = 10;
+      let { randomCollectionName, ref, stocks, names } = await collectionHarness(afs, ITEMS);
+      const nextId = ref.doc('a').id;
+      let count = 0;
+
+      const sub = stocks.snapshotChanges(['added', 'modified']).skip(1).take(2).subscribe(data => {
+        count += 1;
+        if (count == 1) {
+          const change = data.filter(x => x.payload.doc.id === nextId)[0];
+          expect(data.length).toEqual(ITEMS + 1);
+          expect(change.payload.doc.data().price).toEqual(2);
+          expect(change.type).toEqual('added');
+          delayUpdate(stocks, names[0], { price: 2 });
+        }
+        if (count == 2) {
+          const change = data.filter(x => x.payload.doc.id === names[0])[0];
+          expect(data.length).toEqual(ITEMS + 1);
+          expect(change.payload.doc.data().price).toEqual(2);
+          expect(change.type).toEqual('modified');
+        }
+      }).add(() => {
+        deleteThemAll(names, ref).then(done).catch(done.fail);
+      });
+
+      names = names.concat([nextId]);
+      delayAdd(stocks, nextId, { price: 2 });
+    });
+
     it('should be able to filter snapshotChanges() types - removed', async (done) => {
       const ITEMS = 10;
       const { randomCollectionName, ref, stocks, names } = await collectionHarness(afs, ITEMS);