test(internal/testutil): fix race when accessing trace spans

bigquery/oc_test.go

@@ -32,7 +32,7 @@ func TestOCTracing(t *testing.T) {
 	q := client.Query("select *")
 	q.Run(ctx) // Doesn't matter if we get an error; span should be created either way
 
-	if len(te.Spans) == 0 {
+	if len(te.Spans()) == 0 {
 		t.Fatalf("Expected some spans to be created, but got %d", 0)
 	}
 }

datastore/oc_test.go

@@ -37,7 +37,7 @@ func TestOCTracing(t *testing.T) {
 		t.Fatalf("client.Put: %v", err)
 	}
 
-	if len(te.Spans) == 0 {
+	if len(te.Spans()) == 0 {
 		t.Fatalf("Expected some span to be created, but got %d", 0)
 	}
 }

internal/testutil/trace.go

@@ -27,7 +27,7 @@ import (
 // TestExporter is a test utility exporter. It should be created with NewtestExporter.
 type TestExporter struct {
 	mu    sync.Mutex
-	Spans []*trace.SpanData
+	spans []*trace.SpanData
 
 	Stats chan *view.Data
 	Views []*view.View
@@ -56,7 +56,16 @@ func NewTestExporter(views ...*view.View) *TestExporter {
 func (te *TestExporter) ExportSpan(s *trace.SpanData) {
 	te.mu.Lock()
 	defer te.mu.Unlock()
-	te.Spans = append(te.Spans, s)
+	te.spans = append(te.spans, s)
+}
+
+// Spans returns the exported spans.
+func (te *TestExporter) Spans() []*trace.SpanData {
+	te.mu.Lock()
+	defer te.mu.Unlock()
+	spans := make([]*trace.SpanData, len(te.spans))
+	copy(spans, te.spans)
+	return spans
 }
 
 // ExportView exports a view.

internal/trace/trace_test.go

@@ -63,7 +63,7 @@ func TestStartSpan_OpenCensus(t *testing.T) {
 	if IsOpenTelemetryTracingEnabled() {
 		t.Errorf("got true, want false")
 	}
-	spans := te.Spans
+	spans := te.Spans()
 	if len(spans) != 1 {
 		t.Fatalf("got %d, want 1", len(spans))
 	}

spanner/client_test.go

@@ -4548,12 +4548,11 @@ func TestClient_DoForEachRow_ShouldNotEndSpanWithIteratorDoneError(t *testing.T)
 	case <-time.After(1 * time.Second):
 		t.Fatal("No stats were exported before timeout")
 	}
-	// Preferably we would want to lock the TestExporter here, but the mutex TestExporter.mu is not exported, so we
-	// cannot do that.
-	if len(te.Spans) == 0 {
+	spans := te.Spans()
+	if len(spans) == 0 {
 		t.Fatal("No spans were exported")
 	}
-	s := te.Spans[len(te.Spans)-1].Status
+	s := spans[len(spans)-1].Status
 	if s.Code != int32(codes.OK) {
 		t.Errorf("Span status mismatch\nGot: %v\nWant: %v", s.Code, codes.OK)
 	}
@@ -4598,12 +4597,11 @@ func TestClient_DoForEachRow_ShouldEndSpanWithQueryError(t *testing.T) {
 	case <-time.After(1 * time.Second):
 		t.Fatal("No stats were exported before timeout")
 	}
-	// Preferably we would want to lock the TestExporter here, but the mutex TestExporter.mu is not exported, so we
-	// cannot do that.
-	if len(te.Spans) == 0 {
+	spans := te.Spans()
+	if len(spans) == 0 {
 		t.Fatal("No spans were exported")
 	}
-	s := te.Spans[len(te.Spans)-1].Status
+	s := spans[len(spans)-1].Status
 	if s.Code != int32(codes.InvalidArgument) {
 		t.Errorf("Span status mismatch\nGot: %v\nWant: %v", s.Code, codes.InvalidArgument)
 	}
@@ -5366,12 +5364,11 @@ func checkBatchWriteSpan(t *testing.T, errors []error, code codes.Code) {
 	case <-time.After(1 * time.Second):
 		t.Fatal("No stats were exported before timeout")
 	}
-	// Preferably we would want to lock the TestExporter here, but the mutex TestExporter.mu is not exported, so we
-	// cannot do that.
-	if len(te.Spans) == 0 {
+	spans := te.Spans()
+	if len(spans) == 0 {
 		t.Fatal("No spans were exported")
 	}
-	s := te.Spans[len(te.Spans)-1].Status
+	s := spans[len(spans)-1].Status
 	if s.Code != int32(code) {
 		t.Errorf("Span status mismatch\nGot: %v\nWant: %v", s.Code, code)
 	}

storage/integration_test.go

@@ -5675,7 +5675,7 @@ func TestIntegration_OCTracing(t *testing.T) {
 		bkt := client.Bucket(bucket)
 		bkt.Attrs(ctx)
 
-		if len(te.Spans) == 0 {
+		if len(te.Spans()) == 0 {
 			t.Fatalf("Expected some spans to be created, but got %d", 0)
 		}
 	})