kiss tests: Test TCP connection failure handling

tests/test_kiss/test_tcp.py

@@ -58,3 +58,69 @@ async def _create_connection(proto_factory, **kwargs):
     finally:
         # Restore mock
         loop.create_connection = orig_create_connection
+
+
+@asynctest
+async def test_open_connection_fail():
+    # This will receive the arguments passed to create_connection
+    connection_args = {}
+
+    loop = get_event_loop()
+
+    # Stub the create_connection method
+    orig_create_connection = loop.create_connection
+
+    async def _create_connection(proto_factory, **kwargs):
+        # proto_factory should give us a KISSProtocol object
+        protocol = proto_factory()
+        assert isinstance(protocol, kiss.KISSProtocol)
+
+        connection_args.update(kwargs)
+        raise IOError("Connection failed")
+
+    loop.create_connection = _create_connection
+
+    try:
+        device = kiss.TCPKISSDevice(
+            host="localhost",
+            port=5432,
+            loop=loop,
+            log=logging.getLogger(__name__),
+        )
+
+        failures = []
+
+        def _on_fail(**kwargs):
+            failures.append(kwargs)
+
+        device.failed.connect(_on_fail)
+
+        await device._open_connection()
+
+        # Expect a connection attempt to have been made
+        assert connection_args == dict(
+            host="localhost",
+            port=5432,
+            ssl=None,
+            family=0,
+            proto=0,
+            flags=0,
+            sock=None,
+            local_addr=None,
+            server_hostname=None,
+        )
+
+        # Connection should be in the failed state
+        assert device.state == kiss.KISSDeviceState.FAILED
+
+        # Failure should have been reported
+        assert failures
+        failure = failures.pop(0)
+
+        assert failure.pop("action") == "open"
+        (ex_c, ex_v, _) = failure.pop("exc_info")
+        assert ex_c is IOError
+        assert str(ex_v) == "Connection failed"
+    finally:
+        # Restore mock
+        loop.create_connection = orig_create_connection