filters/scheduler: wait for spans finishing in lifo errors test

The tests was introduced by #1944
It may happen that not all spans are finished by the time test verifies
response results (because spans are closed after response has been
served).

This change waits for all mock spans to finish and forces scheduler
metrics update.

Signed-off-by: Alexander Yastrebov <[email protected]>

filters/scheduler/lifo_test.go

@@ -6,13 +6,15 @@ import (
 	"net/http/httptest"
 	"net/url"
 	"sync"
+	"sync/atomic"
 	"testing"
 	"time"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
 	"github.com/aryszka/jobqueue"
+	"github.com/opentracing/opentracing-go"
 	"github.com/opentracing/opentracing-go/mocktracer"
 	"github.com/zalando/skipper/eskip"
 	"github.com/zalando/skipper/filters"
@@ -301,6 +303,38 @@ func TestNewLIFO(t *testing.T) {
 	}
 }
 
+type testTracer struct {
+	*mocktracer.MockTracer
+	spans int32
+}
+
+func (t *testTracer) Reset() {
+	atomic.StoreInt32(&t.spans, 0)
+	t.MockTracer.Reset()
+}
+
+func (t *testTracer) StartSpan(operationName string, opts ...opentracing.StartSpanOption) opentracing.Span {
+	atomic.AddInt32(&t.spans, 1)
+	return t.MockTracer.StartSpan(operationName, opts...)
+}
+
+func (t *testTracer) FinishedSpans() []*mocktracer.MockSpan {
+	timeout := time.After(1 * time.Second)
+	retry := time.NewTicker(100 * time.Millisecond)
+	defer retry.Stop()
+	for {
+		finished := t.MockTracer.FinishedSpans()
+		if len(finished) == int(atomic.LoadInt32(&t.spans)) {
+			return finished
+		}
+		select {
+		case <-retry.C:
+		case <-timeout:
+			return nil
+		}
+	}
+}
+
 func TestLifoErrors(t *testing.T) {
 	backend := httptest.NewServer(http.HandlerFunc(func(_ http.ResponseWriter, _ *http.Request) {
 		time.Sleep(time.Second)
@@ -334,7 +368,7 @@ func TestLifoErrors(t *testing.T) {
 
 	<-rt.FirstLoad()
 
-	tracer := mocktracer.New()
+	tracer := &testTracer{MockTracer: mocktracer.New()}
 	pr := proxy.WithParams(proxy.Params{
 		Routing:     rt,
 		OpenTracing: &proxy.OpenTracingParams{Tracer: tracer},
@@ -366,6 +400,8 @@ func TestLifoErrors(t *testing.T) {
 		503: 8, // were refused due to full queue
 	}, codes)
 
+	reg.UpdateMetrics()
+
 	metrics.WithCounters(func(counters map[string]int64) {
 		assert.Equal(t, int64(7), counters["lifo.aroute.error.timeout"])
 		assert.Equal(t, int64(8), counters["lifo.aroute.error.full"])

scheduler/scheduler.go

@@ -390,15 +390,15 @@ func (r *Registry) measure() {
 		for {
 			select {
 			case <-time.After(r.options.MetricsUpdateTimeout):
-				r.updateMetrics()
+				r.UpdateMetrics()
 			case <-r.quit:
 				return
 			}
 		}
 	}()
 }
 
-func (r *Registry) updateMetrics() {
+func (r *Registry) UpdateMetrics() {
 	r.mu.Lock()
 	defer r.mu.Unlock()