anchor.diff:          expect(filteredFlowers.values.contains("chicory"), isTrue);
           expect(filteredFlowers.values.contains("sunflower"), isFalse);
         });
  +
  +      test("startAt", () async {
  +        ref = database.ref("flowers");
  +        ref.push("rose");
  +        ref.push("tulip");
  +        ref.push("chicory");
  +        ref.push("sunflower");
  +
  +        var event = await ref.orderByValue().startAt("rose").once("value");
  +        var filteredFlowers = event.snapshot.val();
  +
  +        expect(filteredFlowers.length, 3);
  +        expect(filteredFlowers.values.contains("sunflower"), isTrue);
  +        expect(filteredFlowers.values.contains("chicory"), isFalse);
  +      });
  +
  +      test("equalTo", () async {
  +        ref = database.ref("flowers");
  +        ref.push("rose");
  +        ref.push("tulip");
  +
  +        var event = await ref.orderByValue().equalTo("rose").once("value");
  +        var flower = event.snapshot.val();
  +
  +        expect(flower, isNotNull);
  +        expect(flower.length, 1);
  +        expect(flower.values.first, "rose");
  +      });
       });
     });
   }
  
positive.code: 
        test("parent", () {
          var childRef = ref.child("text");
          expect(childRef, isNotNull);
          expect(childRef.parent.toString(), "${databaseUrl}/messages");
        });
  
  
negative.code:       });
  
        test("endAt", () async {
          ref = database.ref("flowers");
          ref.push("rose");
          ref.push("tulip");
          ref.push("chicory");
  