Verify that baggage is passed through to the child span (jaegertracin…

…g#44)

span_test.go

@@ -1,8 +1,10 @@
 package jaeger
 
 import (
-	"github.com/stretchr/testify/assert"
 	"testing"
+
+	"github.com/opentracing/opentracing-go"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestBaggageIterator(t *testing.T) {
@@ -12,20 +14,28 @@ func TestBaggageIterator(t *testing.T) {
 	sp1 := tracer.StartSpan("s1").(*span)
 	sp1.SetBaggageItem("Some_Key", "12345")
 	sp1.SetBaggageItem("Some-other-key", "42")
+	expectedBaggage := map[string]string{"some-key": "12345", "some-other-key": "42"}
+	assertBaggage(t, sp1, expectedBaggage)
 
-	b := make(map[string]string)
-	sp1.Context().ForeachBaggageItem(func(k, v string) bool {
-		b[k] = v
-		return true
-	})
-	assert.Equal(t, map[string]string{"some-key": "12345", "some-other-key": "42"}, b)
+	b := extractBaggage(sp1, false) // break out early
+	assert.Equal(t, 1, len(b), "only one baggage item should be extracted")
 
-	b = make(map[string]string)
-	sp1.Context().ForeachBaggageItem(func(k, v string) bool {
+	sp2 := tracer.StartSpan("s2", opentracing.ChildOf(sp1.Context()))
+	assertBaggage(t, sp2, expectedBaggage) // child inherits the same baggage
+}
+
+func assertBaggage(t *testing.T, sp opentracing.Span, expected map[string]string) {
+	b := extractBaggage(sp, true)
+	assert.Equal(t, expected, b)
+}
+
+func extractBaggage(sp opentracing.Span, allItems bool) map[string]string {
+	b := make(map[string]string)
+	sp.Context().ForeachBaggageItem(func(k, v string) bool {
 		b[k] = v
-		return false // break out early
+		return allItems
 	})
-	assert.Equal(t, 1, len(b), "only one baggage item should be extracted")
+	return b
 }
 
 func TestSpanProperties(t *testing.T) {