test(ocpp): stop test chargers after the server (#1712)

go/internal/ocpp/auth_test.go

@@ -288,7 +288,7 @@ func TestPerChargerCredentialOverTheWire(t *testing.T) {
 		cp := ocpp16.NewChargePoint(id, nil, client)
 		err := cp.Start(fmt.Sprintf("ws://127.0.0.1:%d", port))
 		if err == nil {
-			t.Cleanup(cp.Stop)
+			stopAfterServer(t, srv, cp.Stop)
 		}
 		return err
 	}

go/internal/ocpp/charging_needs_test.go

@@ -33,7 +33,7 @@ func connectStationForNeeds(t *testing.T, srv *Server, port int, id string) ocpp
 		t.Fatalf("charging station connect: %v", err)
 	}
 	var once sync.Once
-	t.Cleanup(func() { once.Do(cs.Stop) })
+	stopAfterServer(t, srv, func() { once.Do(cs.Stop) })
 
 	if _, err := cs.BootNotification(provisioning.BootReasonPowerUp, "Dawn", "Charge Amps"); err != nil {
 		t.Fatalf("boot: %v", err)

go/internal/ocpp/control_test.go

@@ -114,7 +114,7 @@ func connectCharger(t *testing.T, srv *Server, port int, id string) (ocpp16.Char
 	}
 	var once sync.Once
 	stop := func() { once.Do(cp.Stop) }
-	t.Cleanup(stop)
+	stopAfterServer(t, srv, stop)
 
 	if _, err := cp.BootNotification("Dawn", "Charge Amps"); err != nil {
 		t.Fatalf("boot: %v", err)

go/internal/ocpp/control_v201_test.go

@@ -121,7 +121,7 @@ func connectStationV201(t *testing.T, srv *Server, port int, id string) (*fakeSt
 	}
 	var once sync.Once
 	stop := func() { once.Do(cs.Stop) }
-	t.Cleanup(stop)
+	stopAfterServer(t, srv, stop)
 
 	station := provisioning.ChargingStationType{Model: "Dawn", VendorName: "Charge Amps"}
 	if _, err := cs.BootNotification(provisioning.BootReasonPowerUp, station.Model, station.VendorName); err != nil {

go/internal/ocpp/identity_test.go

@@ -121,7 +121,7 @@ func TestBootNotificationTakesEitherSerialField(t *testing.T) {
 			if err := cp.Start(fmt.Sprintf("ws://127.0.0.1:%d", port)); err != nil {
 				t.Fatalf("connect: %v", err)
 			}
-			t.Cleanup(cp.Stop)
+			stopAfterServer(t, srv, cp.Stop)
 
 			if _, err := cp.BootNotification("Halo", "Charge Amps", tc.props...); err != nil {
 				t.Fatalf("boot: %v", err)

go/internal/ocpp/server_test.go

@@ -55,6 +55,19 @@ func startServer(t *testing.T, tel *telemetry.Store, approved ...string) (int, *
 	return 0, nil
 }
 
+// stopAfterServer stops a test charger at cleanup, after the server. Core
+// probes each charger it accepts, and ocpp-go v0.19.0's ws.Client.Write checks
+// the connection, then sends without its lock: a probe answered while the
+// charger closes can send on the closed queue and panic (#1712). Server.Stop
+// is idempotent.
+func stopAfterServer(t *testing.T, srv *Server, stop func()) {
+	t.Helper()
+	t.Cleanup(func() {
+		srv.Stop()
+		stop()
+	})
+}
+
 func TestStopIsConcurrentAndIdempotent(t *testing.T) {
 	_, srv := startServer(t, telemetry.NewStore())
 
@@ -80,7 +93,7 @@ func TestBootAndMeterValuesPushDerEV(t *testing.T) {
 	if err := cp.Start(url); err != nil {
 		t.Fatalf("client connect: %v", err)
 	}
-	defer cp.Stop()
+	stopAfterServer(t, srv, cp.Stop)
 
 	if _, err := cp.BootNotification("EaseeHome", "Easee"); err != nil {
 		t.Fatalf("boot: %v", err)
@@ -149,7 +162,7 @@ func TestStartStopTransactionTracksSession(t *testing.T) {
 	if err := cp.Start(fmt.Sprintf("ws://127.0.0.1:%d", port)); err != nil {
 		t.Fatalf("connect: %v", err)
 	}
-	defer cp.Stop()
+	stopAfterServer(t, srv, cp.Stop)
 
 	if _, err := cp.BootNotification("Home", "Easee"); err != nil {
 		t.Fatalf("boot: %v", err)
@@ -200,7 +213,7 @@ func TestPendingChargerIsQuarantinedFromTelemetry(t *testing.T) {
 	if err := cp.Start(fmt.Sprintf("ws://127.0.0.1:%d", port)); err != nil {
 		t.Fatalf("connect: %v", err)
 	}
-	defer cp.Stop()
+	stopAfterServer(t, srv, cp.Stop)
 
 	if _, err := cp.BootNotification("EvilCo", "FakeCharger"); err != nil {
 		t.Fatalf("boot: %v", err)