feat(hour-counter-part): add getter to reaad Partial run-hour counter

also added valid tests

Signed-off-by: Milad Makdesi <milad@id8-engineering.io>

Author: MiladMakdesi

src/em511/em511.py

@@ -47,6 +47,7 @@ class Em511:
     EM511_REGISTER_KWH_PARTIAL = 0x14
     EM511_REGISTER_HOUR_COUNTER = 0x2C
     EM511_REGISTER_LIFETIME_COUNTER = 0x30
+    EM511_REGISTER_HOUR_COUNTER_PART = 0x36
     EM511_REGISTER_DEVICE_ID = 0x2000
     EM511_REGISTER_BAUD_RATE = 0x2001
     EM511_REGISTER_PARITY = 0x2002
@@ -294,6 +295,21 @@ def lifetime_counter(self) -> Decimal:
         value = Decimal(self._unpack(regs, self.EM511_REGISTER_LIFETIME_COUNTER)) / self.SCALE_100
         return round(value, 2)
 
+    @property
+    def hour_counter_part(self) -> Decimal:
+        """Partial run-hour counter (h).
+
+        Returns:
+            Decimal: partial operating tim in hours value.
+
+        Raises:
+            ValueError: If input is at max value or above.
+            ModbusException: If failed to read input register.
+        """
+        regs = self._read_input_registers(self.EM511_REGISTER_HOUR_COUNTER_PART, self.INT32_REG_COUNT)
+        value = Decimal(self._unpack(regs, self.EM511_REGISTER_HOUR_COUNTER_PART)) / self.SCALE_100
+        return round(value, 2)
+
     @property
     def password(self) -> int:
         """Password.

src/em511/test_em511.py

@@ -331,6 +331,38 @@ def test_get_lifetime_counter() -> None:
         _ = meter.lifetime_counter
 
 
+def test_get_life_time_counter() -> None:
+    """Test Get hour_counter_partial."""
+    client = MagicMock()
+    mock_result = MagicMock()
+    mock_result.isError.return_value = False
+    meter = Em511(1, client)
+
+    """Test 1: should pass"""
+    mock_result.registers = [0x2904, 0x0000]
+    client.read_input_registers.return_value = mock_result
+    value = meter.hour_counter_part
+    assert value == Decimal("105.0")
+
+    """Test 2: Should pass."""
+    mock_result.registers = [0x1860, 0x0023]
+    client.read_input_registers.return_value = mock_result
+    value = meter.hour_counter_part
+    assert value == Decimal("23000.0")
+
+    """Test 3: Should raise exception due to more registers in use than allowed."""
+    mock_result.registers = [0x1860, 0x0023, 0x4244]
+    client.read_input_registers.return_value = mock_result
+    with pytest.raises(ValueError, match="Unexpected register count:"):
+        _ = meter.hour_counter_part
+
+    """Test 4: Should raise exception if input value exceeds maximum value, display shows 'EEE', 32-bit register."""
+    mock_result.registers = [0xFFFF, 0x7FFF]
+    client.read_input_registers.return_value = mock_result
+    with pytest.raises(ValueError, match="Input overflow EEE for 32-bit register: "):
+        _ = meter.hour_counter_part
+
+
 def test_get_password() -> None:
     """Test Get password."""
     client = MagicMock()