add new micro tracer methods

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

opentracing_test.go

@@ -0,0 +1,32 @@
+package opentracing
+
+import (
+	"context"
+	"testing"
+
+	"github.com/opentracing/opentracing-go/mocktracer"
+	"go.unistack.org/micro/v4/metadata"
+	"go.unistack.org/micro/v4/tracer"
+)
+
+func TestTraceID(t *testing.T) {
+	md := metadata.New(1)
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	ctx = metadata.NewIncomingContext(ctx, md)
+
+	tr := NewTracer(Tracer(mocktracer.New()))
+	if err := tr.Init(); err != nil {
+		t.Fatal(err)
+	}
+
+	var sp tracer.Span
+
+	ctx, sp = tr.Start(ctx, "test")
+	if v := sp.TraceID(); v != "43" {
+		t.Fatalf("invalid span trace id %#+v", v)
+	}
+	if v := sp.SpanID(); v != "44" {
+		t.Fatalf("invalid span span id %#+v", v)
+	}
+}