fix(RPM): fix calculation issue with response time

Author: peteyycz

lib/providers/httpTransaction/index.js

@@ -27,7 +27,7 @@ function HttpTransaction(eventBus, options) {
   this.traces = [];
   this.rpmMetrics = {};
   this.totalRequestCount = 0;
-  this.avgResponseTime = 0;
+  this.avgResponseTime = null;
   this.avgRequestCount = 0;
 
   this.on(HttpTransaction.CLIENT_RECV, this.onClientReceive);
@@ -162,13 +162,13 @@ HttpTransaction.prototype.onServerSend = function (data) {
   }
 
   this.collectStatusCode(trace);
-  this.avgResponseTime = this.calculateAvgResponseTime(data.responseTime);
+  this.calculateAvgResponseTime(data.responseTime);
   delete this.partials[data.id];
 };
 
 HttpTransaction.prototype.calculateAvgResponseTime = function (responseTime) {
-  return ((this.avgResponseTime * this.avgRequestCount) +
-    responseTime) / ++this.avgRequestCount || null;
+  this.avgResponseTime = (((this.avgResponseTime * this.avgRequestCount) +
+    responseTime) / ++this.avgRequestCount) || null;
 };
 
 HttpTransaction.prototype.collectStatusCode = function (trace) {
@@ -226,8 +226,8 @@ HttpTransaction.prototype._sendRpm = function () {
 
     this.eventBus.emit(this.eventBus.RPM_METRICS, dataBag);
     this.rpmMetrics = {};
+    this.avgResponseTime = null;
     this.avgRequestCount = 0;
-    this.avgResponseTime = 0;
   }
 };
 

lib/providers/httpTransaction/index.spec.js

@@ -387,5 +387,28 @@ describe('The HttpTransaction module', function () {
 
       done();
     });
+
+    it('calculates average response time', function (done) {
+      var httpTransaction = HttpTransaction.create(eventBus, {});
+
+      expect(httpTransaction.avgResponseTime).to.be.eql(null);
+
+      httpTransaction.calculateAvgResponseTime(2);
+      expect(httpTransaction.avgResponseTime).to.be.eql(2);
+
+      httpTransaction.calculateAvgResponseTime(5);
+      expect(httpTransaction.avgResponseTime).to.be.eql(3.5);
+
+      httpTransaction.calculateAvgResponseTime(8);
+      expect(httpTransaction.avgResponseTime).to.be.eql(5);
+
+      httpTransaction.calculateAvgResponseTime(10);
+      expect(httpTransaction.avgResponseTime).to.be.eql(6.25);
+
+      httpTransaction.calculateAvgResponseTime(10);
+      expect(httpTransaction.avgResponseTime).to.be.eql(7);
+
+      done();
+    });
   });
 });