internal/telemetry: fix flake in TestTelemetryEnabled (#3160)

Author: hannahkm

ddtrace/tracer/telemetry_test.go

@@ -61,7 +61,7 @@ func TestTelemetryEnabled(t *testing.T) {
 		telemetry.Check(t, telemetryClient.Configuration, "span_sample_rules", "[]")
 		if metrics, ok := telemetryClient.Metrics[telemetry.NamespaceGeneral]; ok {
 			if initTime, ok := metrics["init_time"]; ok {
-				assert.True(t, initTime > 0)
+				assert.True(t, initTime > 0, "expected positive init time, but got %f", initTime)
 				return
 			}
 			t.Fatalf("could not find general init time in telemetry client metrics")

internal/telemetry/telemetrytest/telemetrytest.go

@@ -73,6 +73,9 @@ func (c *MockClient) Record(ns telemetry.Namespace, _ telemetry.MetricKind, name
 	c.On("Gauge", ns, name, val, tags, common).Return()
 	c.On("Record", ns, name, val, tags, common).Return()
 	_ = c.Called(ns, name, val, tags, common)
+
+	c.mu.Lock()
+	defer c.mu.Unlock()
 	// record the val for tests that assert based on the value
 	if _, ok := c.Metrics[ns]; !ok {
 		c.Metrics[ns] = map[string]float64{}