Tests: improve SYNC coverage (#531)

Author: erlend-aasland

test/test_sync.py

@@ -1,29 +1,77 @@
+import threading
 import unittest
+
+import can
 import canopen
 
 
+PERIOD = 0.01
+TIMEOUT = PERIOD * 10
+
+
 class TestSync(unittest.TestCase):
+    def setUp(self):
+        self.net = canopen.Network()
+        self.net.connect(interface="virtual")
+        self.sync = canopen.sync.SyncProducer(self.net)
+        self.rxbus = can.Bus(interface="virtual")
 
-    def test_sync_producer(self):
-        network = canopen.Network()
-        network.connect(interface="virtual", receive_own_messages=True)
-        producer = canopen.sync.SyncProducer(network)
-        producer.transmit()
-        msg = network.bus.recv(1)
-        network.disconnect()
+    def tearDown(self):
+        self.net.disconnect()
+        self.rxbus.shutdown()
+
+    def test_sync_producer_transmit(self):
+        self.sync.transmit()
+        msg = self.rxbus.recv(TIMEOUT)
+        self.assertIsNotNone(msg)
         self.assertEqual(msg.arbitration_id, 0x80)
         self.assertEqual(msg.dlc, 0)
 
-    def test_sync_producer_counter(self):
-        network = canopen.Network()
-        network.connect(interface="virtual", receive_own_messages=True)
-        producer = canopen.sync.SyncProducer(network)
-        producer.transmit(2)
-        msg = network.bus.recv(1)
-        network.disconnect()
+    def test_sync_producer_transmit_count(self):
+        self.sync.transmit(2)
+        msg = self.rxbus.recv(TIMEOUT)
+        self.assertIsNotNone(msg)
         self.assertEqual(msg.arbitration_id, 0x80)
         self.assertEqual(msg.dlc, 1)
         self.assertEqual(msg.data, b"\x02")
 
+    def test_sync_producer_start_invalid_period(self):
+        with self.assertRaises(ValueError):
+            self.sync.start(0)
+
+    def test_sync_producer_start(self):
+        self.sync.start(PERIOD)
+        self.addCleanup(self.sync.stop)
+
+        acc = []
+        condition = threading.Condition()
+
+        def hook(id_, data, ts):
+            item = id_, data, ts
+            acc.append(item)
+            condition.notify()
+
+        def periodicity():
+            # Check if periodicity has been established.
+            if len(acc) > 2:
+                delta = acc[-1][2] - acc[-2][2]
+                return round(delta, ndigits=1) == PERIOD
+
+        # Sample messages.
+        with condition:
+            condition.wait_for(periodicity, TIMEOUT)
+        for msg in acc:
+            self.assertIsNotNone(msg)
+            self.assertEqual(msg[0], 0x80)
+            self.assertEqual(msg[1], b"")
+
+        self.sync.stop()
+        # A message may have been in flight when we stopped the timer,
+        # so allow a single failure.
+        msg = self.rxbus.recv(TIMEOUT)
+        if msg is not None:
+            self.assertIsNone(self.net.bus.recv(TIMEOUT))
+
+
 if __name__ == "__main__":
     unittest.main()