When get_data fails the legend should be cleared

src/app/panels/graph/module.js

@@ -203,6 +203,7 @@ function (angular, app, $, _, kbn, moment, TimeSeries) {
           $scope.panelMeta.loading = false;
           $scope.panelMeta.error = err.message || "Timeseries data request error";
           $scope.inspector.error = err;
+          $scope.legend = [];
           $scope.render([]);
         });
     };

src/test/specs/graph-ctrl-specs.js

@@ -36,6 +36,20 @@ define([
         var data = ctx.scope.render.getCall(0).args[0];
         expect(data.length).to.be(2);
       });
+
+      describe('get_data failure following success', function() {
+        beforeEach(function() {
+          ctx.datasource.query = sinon.stub().returns(ctx.$q.reject('Datasource Error'));
+          ctx.scope.get_data();
+          ctx.scope.$digest();
+        });
+
+        it('should clear the legend data', function() {
+          expect(ctx.scope.legend).to.eql([]);
+        });
+
+      });
+
     });
 
   });