fix TCP client example and unittest for incremented value due to on_get callback

Author: brainelectronics

examples/tcp_client_example.py

@@ -107,7 +107,7 @@ def my_inputs_register_get_cb(reg_type, address, val):
 
     # any operation should be as short as possible to avoid response timeouts
     # It would be also possible to read the leatest pin state at this time
-    val += 1
+    val[0] += 1
     client.set_ist(address=address, value=val)
     print('Incremented current value by +1 before sending response')
 

tests/test_tcp_example.py

@@ -542,6 +542,10 @@ def test_read_input_registers_single(self) -> None:
         expectation = \
             (self._register_definitions['IREGS']['EXAMPLE_IREG']['val'], )
 
+        # due to value increment by registered callback in
+        # tcp_client_example.py, see #31 and #51
+        expectation[0] += 1
+
         register_value = self._host.read_input_registers(
             slave_addr=self._client_addr,
             starting_addr=ireg_address,