added tests

firebase-query.html

@@ -340,6 +340,7 @@
             }.bind(this))
 
             this.set('data', data);
+            this._setExists(true);
           }
 
           const query = this.query

test/firebase-document.html

@@ -65,6 +65,59 @@
           });
         }
       });
+
+     function pushFirebaseValue(path, value) {
+       return firebase.app('test').database().ref(path).push(value);
+      }
+
+      function clearFirebaseValue(path) {
+        return firebase.app('test').database().ref(path).set(null);
+      }
+
+      var makeObject;
+      var root;
+
+      setup(function() {
+        var objectId = 0;
+        makeObject = function(value) {
+          return {
+            val: value || objectId++
+          };
+        };
+
+        return pushFirebaseValue('/test', { ignore: 'me' }).then(function(snapshot) {
+          root = '/test/' + snapshot.key;
+        });
+      });
+
+      suite('exists attribute', function() {
+         var query;
+
+        setup(function() {
+          query = fixture('BasicStorage');
+          query.path = root + '/list';
+          return query.transactionsComplete;
+        });
+
+        test('exists is null when we change the path', function() {
+          query.path = '/myNewPath';
+          expect(query.exists).to.be.equal(null);
+        });
+
+        test('exists is true when we have data false when we remove it.', function() {
+          var object = makeObject();
+
+          return pushFirebaseValue(query.path, object).then(function() {
+            expect(query.exists).to.be.equal(true);
+          }).then(function(){
+            clearFirebaseValue(query.path);
+          }).then(function() {
+            expect(query.exists).to.be.equal(false);
+          });
+        });
+
+      });
+
     });
   </script>
 </body>

test/firebase-query.html

@@ -176,6 +176,7 @@
           var object = makeObject();
 
           return pushFirebaseValue(query.path, object).then(function() {
+            expect(query.exists).to.be.equal(true);
             expect(query.data.length).to.be.equal(1);
             expect(query.data[0]).to.be.ok;
             expect(query.data[0].val).to.be.equal(object.val);
@@ -241,6 +242,22 @@
             expect(query.data[0].foo).to.be.eql(undefined);
           });
         });
+
+        test('exists is null when template is stamped', function() {
+          expect(query.exists).to.be.equal(null);
+        })
+
+        test('exists is true when we have data false when we remove it.', function() {
+          var object = makeObject();
+
+          return pushFirebaseValue(query.path, object).then(function() {
+            expect(query.exists).to.be.equal(true);
+          }).then(function(){
+            clearFirebaseValue(query.path);
+          }).then(function() {
+            expect(query.exists).to.be.equal(false);
+          });
+        });
       });
 
       suite('querying against leaf node collections', function() {