Small fix to graphiteDatasource and sending cacheTimeout undefined, reintroduced this bug yesterday, added unit test so it should not appear again

src/app/services/graphite/graphiteDatasource.js

@@ -251,7 +251,9 @@ function (angular, _, $, config, kbn, moment) {
 
       _.each(options, function (value, key) {
         if ($.inArray(key, graphite_options) === -1) { return; }
-        clean_options.push(key + "=" + encodeURIComponent(value));
+        if (value) {
+          clean_options.push(key + "=" + encodeURIComponent(value));
+        }
       });
 
       return clean_options;

src/test/specs/graphiteDatasource-specs.js

@@ -18,7 +18,7 @@ define([
       var query = {
         range: { from: 'now-1h', to: 'now' },
         targets: [{ target: 'prod1.count' }, {target: 'prod2.count'}],
-        maxDataPoints: 500
+        maxDataPoints: 500,
       };
 
       var response = [{ target: 'prod1.count', points: [[10, 1], [12,1]], }];
@@ -46,6 +46,11 @@ define([
         expect(params).to.contain('until=now');
       });
 
+      it('should exclude undefined params', function() {
+        var params = request.split('&');
+        expect(params).to.not.contain('cacheTimeout=undefined');
+      });
+
       it('should return series list', function() {
         expect(results.data.length).to.be(1);
         expect(results.data[0].target).to.be('prod1.count');