From 2e95e4b1ea81154b1a4e91f69d37e0e1cfc1d995 Mon Sep 17 00:00:00 2001
From: Austin Hartzheim <austin.hartzheim@target.com>
Date: Mon, 26 Mar 2018 21:22:18 -0500
Subject: [PATCH] Add tests for the trace.Inject function.

---
 trace/trace_test.go | 75 ++++++++++++++++++++++++++-------------------
 1 file changed, 43 insertions(+), 32 deletions(-)

diff --git a/trace/trace_test.go b/trace/trace_test.go
index 46cffdc0f..15eefe784 100644
--- a/trace/trace_test.go
+++ b/trace/trace_test.go
@@ -1,54 +1,65 @@
 package trace
 
 import (
-	opentracing "github.com/opentracing/opentracing-go"
-	"github.com/opentracing/opentracing-go/ext"
-	mocktracer "github.com/opentracing/opentracing-go/mocktracer"
 	"net/http"
 	"testing"
+
+	opentracing "github.com/opentracing/opentracing-go"
+	mocktracer "github.com/opentracing/opentracing-go/mocktracer"
+	zipkin "github.com/openzipkin/zipkin-go-opentracing"
+	zipkintypes "github.com/openzipkin/zipkin-go-opentracing/types"
 )
 
-func mimicTracerInject(req *http.Request) {
-	// TODO maybe replace this will a call to opentracing.GlobalTracer().Inject()
-	req.Header.Add("X-B3-TraceId", "1234562345678")
-	req.Header.Add("X-B3-SpanId", "123456789")
-	req.Header.Add("X-B3-ParentSpanId", "123456789")
-	req.Header.Add("X-B3-Flags", "1")
-}
+const testServiceName = "TEST-SERVICE"
 
-// go test -v ./trace
 func TestInjectHeaders(t *testing.T) {
-	serviceName := "TESTING"
-
-	req, err := http.NewRequest("GET", "http://example.com", nil)
-	if err != nil {
-		t.Error("Error when creating new request.")
-		t.Fail()
-	}
-	mimicTracerInject(req)
-
 	mt := mocktracer.New()
 	opentracing.SetGlobalTracer(mt)
 	globalTracer := opentracing.GlobalTracer()
+	span := globalTracer.StartSpan(testServiceName)
 
-	var span opentracing.Span
-	if globalTracer != nil {
-		spanCtx, err := globalTracer.Extract(opentracing.HTTPHeaders, opentracing.HTTPHeadersCarrier(req.Header))
-		if err != nil {
-			span = globalTracer.StartSpan(serviceName)
-		} else {
-			span = globalTracer.StartSpan(serviceName, ext.RPCServerOption(spanCtx))
-		}
+	req, _ := http.NewRequest("GET", "http://example.com", nil)
+	InjectHeaders(span, req)
+
+	if req.Header.Get("Mockpfx-Ids-Traceid") == "" {
+		t.Error("Inject did not set the Traceid in the request.")
+		t.Fail()
 	}
+	if req.Header.Get("Mockpfx-Ids-Spanid") == "" {
+		t.Error("Inject did not set the Spanid in the request.")
+		t.Fail()
+	}
+}
 
-	InjectHeaders(span, req)
+func TestInjectHeadersWithParentSpan(t *testing.T) {
+	parentSpanId := uint64(12345)
+	parentSpanContext := zipkin.SpanContext{
+		SpanID:  parentSpanId,
+		TraceID: zipkintypes.TraceID{High: uint64(1234), Low: uint64(4321)},
+	}
+
+	tracer, _ := zipkin.NewTracer(nil)
+	opentracing.SetGlobalTracer(tracer)
+	globalTracer := opentracing.GlobalTracer()
+	childSpan := globalTracer.StartSpan(testServiceName+"-CHILD", opentracing.ChildOf(parentSpanContext))
+
+	req, _ := http.NewRequest("GET", "http://example.com", nil)
+	InjectHeaders(childSpan, req)
 
 	if req.Header.Get("X-B3-Traceid") == "" {
-		t.Error("Zipkin headers not set in request.")
+		t.Error("Inject did not set the Traceid in the request.")
+		t.Fail()
+	}
+	if req.Header.Get("X-B3-Spanid") == "" {
+		t.Error("Inject did not set the Spanid in the request.")
+		t.Fail()
+	}
+	if req.Header.Get("X-B3-Parentspanid") != "0000000000003039" {
+		t.Error("Inject did not set the correct Parentspanid in the request.")
 		t.Fail()
 	}
-	if req.Header.Get("X-B3-Traceid") != "1234562345678" {
-		t.Error("Zipkin headers do not match the values set.")
+	if req.Header.Get("x-B3-Traceid") != "00000000000004d200000000000010e1" {
+		t.Error("Inject did not reuse the Traceid from the parent span")
 		t.Fail()
 	}
 }