feat(baud-rate): Add setter to set baud rate

Also added valid tests

Signed-off-by: Bobo Bäck Engström <bobo@id8-engineering.io>

Author: Dexter9532

src/em511/em511.py

@@ -426,8 +426,7 @@ def password(self, value: int) -> None:
     def device_id(self, value: int) -> None:
         """Device id.
 
-        Value:
-            Range 1 - 247
+        Range 1 - 247
 
         Args:
             value (int): Set device id.
@@ -440,3 +439,22 @@ def device_id(self, value: int) -> None:
             msg = f"Invalid device id value: {value}. Must be between 1 and 247."
             raise ValueError(msg)
         self._write_register(self.EM511_REGISTER_DEVICE_ID, value)
+
+    @baud_rate.setter
+    def baud_rate(self, value: int) -> None:
+        """Baud rate.
+
+        1=9.6kbps, 2=19.2kbps, 3=38.4kbps,
+        4=57.6kbps, 5=115.2kbps (default=1).
+
+        Args:
+            value (int): Set baud rate.
+
+        Raises:
+            ModbusException: If failed to write to single register.
+            ValueError: If baud rate value is out of range.
+        """
+        if not (self.BAUD_RATE_MIN_VALUE <= value <= self.BAUD_RATE_MAX_VALUE):
+            msg = f"Invalid baud rate value: {value}. Must be between 1 and 5."
+            raise ValueError(msg)
+        self._write_register(self.EM511_REGISTER_BAUD_RATE, value)

src/em511/test_em511.py

@@ -584,3 +584,41 @@ def test_set_device_id() -> None:
     client.write_register.return_value = mock_result
     meter.device_id = 1
     client.write_register.assert_called_once_with(address=8192, value=1, device_id=1)
+
+
+def test_set_baud_rate() -> None:
+    """Test Set baud rate."""
+    client = MagicMock()
+    mock_result = MagicMock()
+    mock_result.isError.return_value = False
+    meter = Em511(1, client)
+
+    """Test 1: Set baud rate"""
+    mock_result.registers = [8193]
+    client.write_register.return_value = mock_result
+    meter.baud_rate = 2
+    client.write_register.assert_called_once_with(address=8193, value=2, device_id=1)
+
+    client.write_register.reset_mock()
+
+    """Test 2: Try set baud rate out of range."""
+    with pytest.raises(ValueError, match="Invalid baud rate value:"):
+        meter.baud_rate = 6
+
+    """Test 3: Try set baud rate out of range."""
+    with pytest.raises(ValueError, match="Invalid baud rate value:"):
+        meter.baud_rate = 0
+
+    """Test 4: Try set baud rate at maximum value."""
+    mock_result.registers = [8193]
+    client.write_register.return_value = mock_result
+    meter.baud_rate = 5
+    client.write_register.assert_called_once_with(address=8193, value=5, device_id=1)
+
+    client.write_register.reset_mock()
+
+    """Test 5: Try set baud rate at lowest value."""
+    mock_result.registers = [8193]
+    client.write_register.return_value = mock_result
+    meter.baud_rate = 1
+    client.write_register.assert_called_once_with(address=8193, value=1, device_id=1)