Added test with large RTT (#679)

* Added test with large RTT

* Make RTT test for variable filesize

* Cleanup, don't log to new file

* Run RTT test with multiple RTT's (for only 500kB file)

integrationtests/rtt_test.go

@@ -58,9 +58,13 @@ var _ = Describe("non-zero RTT", func() {
 		version := protocol.SupportedVersions[i]
 
 		Context(fmt.Sprintf("with quic version %d", version), func() {
-			It("gets a file with 10ms RTT", func() {
-				runRTTTest(10*time.Millisecond, version)
-			})
+			roundTrips := [...]int{10, 50, 100, 200}
+			for _, rtt := range roundTrips {
+				It(fmt.Sprintf("gets a 500kB file with %dms RTT", rtt), func() {
+					dataMan.GenerateData(dataLen)
+					runRTTTest(time.Duration(rtt)*time.Millisecond, version)
+				})
+			}
 		})
 	}
 })