test: add some attiribution from test function

Signed-off-by: deadprogram <ron@hybridgroup.com>

helpers_test.go

@@ -11,6 +11,7 @@ func floatEquals(a, b float64) bool {
 	return false
 }
 
+// round helper from https://stackoverflow.com/questions/39544571/golang-round-to-nearest-0-05
 func round(x, unit float64) float64 {
 	return float64(int64(x/unit+0.5)) * unit
 }