Add more common operations to Quantity

src/frequenz/quantities/_quantity.py

@@ -139,6 +139,24 @@ def base_value(self) -> float:
         """
         return self._base_value
 
+    def __round__(self, ndigits: int | None = None) -> Self:
+        """Round this quantity to the given number of digits.
+
+        Args:
+            ndigits: The number of digits to round to.
+
+        Returns:
+            The rounded quantity.
+        """
+        return self._new(round(self._base_value, ndigits))
+
+    def __pos__(self) -> Self:
+        """Return this quantity.
+
+        Returns:
+            This quantity.
+        """
+        return self
     @property
     def base_unit(self) -> str | None:
         """Return the base unit of this quantity.

tests/test_quantities.py

@@ -234,6 +234,11 @@ def test_isclose() -> None:
     assert not Fz1(1.024445).isclose(Fz1(1.0))
 
 
+@hypothesis.given(value=st.floats(allow_nan=False, allow_infinity=False))
+@pytest.mark.parametrize("ndigits", [0, 1, 2, 3])
+def test_round(value: float, ndigits: int) -> None:
+    """Test the rounding of the quantities."""
+    assert round(Quantity(value), ndigits) == Quantity(round(value, ndigits))
 def test_addition_subtraction() -> None:
     """Test the addition and subtraction of the quantities."""
     assert Quantity(1) + Quantity(1, exponent=0) == Quantity(2, exponent=0)
@@ -486,6 +491,33 @@ def test_neg() -> None:
     assert -(-pct) == pct
 
 
+def test_pos() -> None:
+    """Test the positive sign of quantities."""
+    power = Power.from_watts(1000.0)
+    assert +power == power
+    assert +(+power) == power
+
+    voltage = Voltage.from_volts(230.0)
+    assert +voltage == voltage
+    assert +(+voltage) == voltage
+
+    current = Current.from_amperes(2)
+    assert +current == current
+    assert +(+current) == current
+
+    energy = Energy.from_kilowatt_hours(6.2)
+    assert +energy == energy
+    assert +(+energy) == energy
+
+    freq = Frequency.from_hertz(50)
+    assert +freq == freq
+    assert +(+freq) == freq
+
+    pct = Percentage.from_fraction(30)
+    assert +pct == pct
+    assert +(+pct) == pct
+
+
 def test_inf() -> None:
     """Test proper formating when using inf in quantities."""
     assert f"{Power.from_watts(float('inf'))}" == "inf W"