unit test for communication timeout

rotator/yaesu/serialport_timeout_test.go

@@ -0,0 +1,46 @@
+package yaesu
+
+import (
+	"bytes"
+	"testing"
+	"time"
+)
+
+func TestSerialPortReadTimeout(t *testing.T) {
+
+	// mock the serial port with Buffers
+	dp := dummyPort{
+		sendBuf: &bytes.Buffer{},
+		rxBuf:   &bytes.Buffer{},
+	}
+
+	yaesu := Yaesu{
+		sp:              &dp,
+		closeCh:         make(chan struct{}),
+		errorCh:         make(chan struct{}),
+		pollingInterval: time.Millisecond * 100,
+	}
+
+	// after 5x pollingInterval the watchdog must kick in
+	// to be on the safe side we wait for 7 pollingIntervals before failure
+	timeout := time.After(yaesu.pollingInterval * 7)
+
+	// the routine will try to query the rotator. But since we just
+	// dump the content in buffer, there is no rotator replying. Hence
+	// the Watchdog must kick in after 5x polling.
+	go yaesu.start()
+	select {
+	case <-yaesu.errorCh:
+		// expected behavior is that the watchdog will close
+		// the error channel.
+		yaesu.Close()
+		timeout = nil
+		time.Sleep(time.Second * 1)
+		return
+	case <-timeout:
+		t.Fatal("Watchdog monitoring the serial port did not launch on read timeout")
+	}
+
+	// workaround - time for teardown needed - otherwise the test crashes on macos
+	dp.Close()
+}