Fix sporadic test failure in otlp exporter http driver (#1906)

* Fix sporadic test failure in otlp exporter http driver

* Shorten driver timeout

exporters/otlp/otlphttp/driver_test.go

@@ -171,15 +171,15 @@ func TestRetry(t *testing.T) {
 }
 
 func TestTimeout(t *testing.T) {
-	mcCfg := mockCollectorConfig{
-		InjectDelay: 100 * time.Millisecond,
-	}
+	delay := make(chan struct{})
+	mcCfg := mockCollectorConfig{Delay: delay}
 	mc := runMockCollector(t, mcCfg)
 	defer mc.MustStop(t)
+	defer func() { close(delay) }()
 	driver := otlphttp.NewDriver(
 		otlphttp.WithEndpoint(mc.Endpoint()),
 		otlphttp.WithInsecure(),
-		otlphttp.WithTimeout(50*time.Millisecond),
+		otlphttp.WithTimeout(time.Nanosecond),
 	)
 	ctx := context.Background()
 	exporter, err := otlp.NewExporter(ctx, driver)
@@ -188,7 +188,7 @@ func TestTimeout(t *testing.T) {
 		assert.NoError(t, exporter.Shutdown(ctx))
 	}()
 	err = exporter.ExportSpans(ctx, otlptest.SingleReadOnlySpan())
-	assert.Equal(t, true, os.IsTimeout(err))
+	assert.Equalf(t, true, os.IsTimeout(err), "expected timeout error, got: %v", err)
 }
 
 func TestRetryFailed(t *testing.T) {

exporters/otlp/otlphttp/mock_collector_test.go

@@ -26,7 +26,6 @@ import (
 	"net/http"
 	"sync"
 	"testing"
-	"time"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -53,7 +52,7 @@ type mockCollector struct {
 
 	injectHTTPStatus  []int
 	injectContentType string
-	injectDelay       time.Duration
+	delay             <-chan struct{}
 
 	clientTLSConfig *tls.Config
 	expectedHeaders map[string]string
@@ -94,8 +93,12 @@ func (c *mockCollector) ClientTLSConfig() *tls.Config {
 }
 
 func (c *mockCollector) serveMetrics(w http.ResponseWriter, r *http.Request) {
-	if c.injectDelay != 0 {
-		time.Sleep(c.injectDelay)
+	if c.delay != nil {
+		select {
+		case <-c.delay:
+		case <-r.Context().Done():
+			return
+		}
 	}
 
 	if !c.checkHeaders(r) {
@@ -139,8 +142,12 @@ func unmarshalMetricsRequest(rawRequest []byte, contentType string) (*collectorm
 }
 
 func (c *mockCollector) serveTraces(w http.ResponseWriter, r *http.Request) {
-	if c.injectDelay != 0 {
-		time.Sleep(c.injectDelay)
+	if c.delay != nil {
+		select {
+		case <-c.delay:
+		case <-r.Context().Done():
+			return
+		}
 	}
 
 	if !c.checkHeaders(r) {
@@ -247,7 +254,7 @@ type mockCollectorConfig struct {
 	Port              int
 	InjectHTTPStatus  []int
 	InjectContentType string
-	InjectDelay       time.Duration
+	Delay             <-chan struct{}
 	WithTLS           bool
 	ExpectedHeaders   map[string]string
 }
@@ -273,7 +280,7 @@ func runMockCollector(t *testing.T, cfg mockCollectorConfig) *mockCollector {
 		metricsStorage:    otlptest.NewMetricsStorage(),
 		injectHTTPStatus:  cfg.InjectHTTPStatus,
 		injectContentType: cfg.InjectContentType,
-		injectDelay:       cfg.InjectDelay,
+		delay:             cfg.Delay,
 		expectedHeaders:   cfg.ExpectedHeaders,
 	}
 	mux := http.NewServeMux()