Readded soc function

tests/test_storage.py

@@ -36,7 +36,7 @@ def test_update(self, battery, power, duration, exp_charge_energy, exp_charge_le
         charge_energy = battery.update(power=power, duration=duration * 3600)
         assert charge_energy == exp_charge_energy * 3600
         assert battery.state()["charge_level"] == exp_charge_level
-        assert math.isclose(battery.state()["soc"], exp_soc)
+        assert math.isclose(battery.soc(), exp_soc)
 
     @pytest.mark.parametrize(
         "power, duration, exp_charge_energy, exp_charge_level, exp_soc",
@@ -68,7 +68,7 @@ def test_update_c_rate(
         charge_energy = battery_c.update(power=power, duration=duration * 60)
         assert charge_energy == exp_charge_energy * 3600
         assert battery_c.state()["charge_level"] == exp_charge_level
-        assert math.isclose(battery_c.state()["soc"], exp_soc)
+        assert math.isclose(battery_c.soc(), exp_soc)
 
     def test_update_fails_if_duration_not_positive(self, battery):
         with pytest.raises(ValueError):
@@ -113,7 +113,7 @@ def test_apply_no_charge_mode(self, battery, policy, power, duration, exp_delta,
         # duration in hours and energy delta in Wh
         delta = policy.apply(power, duration * 3600, battery)
         assert delta == exp_delta * 3600
-        assert math.isclose(battery.state()["soc"], exp_soc)
+        assert math.isclose(battery.soc(), exp_soc)
 
     @pytest.mark.parametrize(
         "power, duration, exp_delta, exp_soc",
@@ -136,7 +136,7 @@ def test_apply_charge(self, battery, policy_charge, power, duration, exp_delta,
         # duration in hours and energy delta in Wh
         delta = policy_charge.apply(power, duration * 3600, battery)
         assert delta == exp_delta * 3600
-        assert math.isclose(battery.state()["soc"], exp_soc)
+        assert math.isclose(battery.soc(), exp_soc)
 
     @pytest.mark.parametrize(
         "power, duration, exp_delta, exp_soc",
@@ -159,7 +159,7 @@ def test_apply_discharge(self, battery, policy_discharge, power, duration, exp_d
         # duration in hours and energy delta in Wh
         delta = policy_discharge.apply(power, duration * 3600, battery)
         assert delta == exp_delta * 3600
-        assert math.isclose(battery.state()["soc"], exp_soc)
+        assert math.isclose(battery.soc(), exp_soc)
 
     @pytest.mark.parametrize(
         "power, duration, exp_delta, exp_soc",
@@ -178,7 +178,7 @@ def test_apply_islanded(self, battery, policy_islanded, power, duration, exp_del
         # duration in hours and energy delta in Wh
         delta = policy_islanded.apply(power, duration * 3600, battery)
         assert delta == exp_delta * 3600
-        assert math.isclose(battery.state()["soc"], exp_soc)
+        assert math.isclose(battery.soc(), exp_soc)
 
     @pytest.mark.parametrize(
         "power, duration, exp_delta",

vessim/storage.py

@@ -18,6 +18,13 @@ def update(self, power: float, duration: int) -> float:
             The total energy in Ws that has been charged/discharged.
         """
 
+    @abstractmethod
+    def soc(self) -> float:
+        """Returns the state-of-charge (SoC) of the battery.
+
+        Values should range between 0 (empty) and 1 (full).
+        """
+
     def set_parameter(self, key: str, value: Any) -> None:
         """Fuction to let a controller update a storage parameter during a simulation using Mosaik.
 
@@ -56,8 +63,8 @@ def __init__(
         self.capacity = capacity
         assert 0 <= initial_soc <= 1
         self.charge_level = capacity * initial_soc
-        self.soc = initial_soc
-        assert 0 <= min_soc <= self.soc
+        self._soc = initial_soc
+        assert 0 <= min_soc <= self._soc
         self.min_soc = min_soc
         self.c_rate = c_rate
 
@@ -72,7 +79,7 @@ def update(self, power: float, duration: int) -> float:
         if duration <= 0.0:
             raise ValueError("Duration needs to be a positive value")
 
-        assert self.min_soc <= self.soc, "Minimum SoC can not be smaller than the current SoC"
+        assert self.min_soc <= self._soc, "Minimum SoC can not be smaller than the current SoC"
         if self.c_rate is not None:
             max_power = self.c_rate * self.capacity
             if power >= max_power:
@@ -99,22 +106,25 @@ def update(self, power: float, duration: int) -> float:
             # Battery can not be discharged further than the minimum state-of-charge
             charged_energy = abs_min_soc - self.charge_level
             self.charge_level = abs_min_soc
-            self.soc = self.min_soc
+            self._soc = self.min_soc
         elif new_charge_level > self.capacity:
             # Battery can not be charged past its capacity
             charged_energy = self.capacity - self.charge_level
             self.charge_level = self.capacity
-            self.soc = 1.0
+            self._soc = 1.0
         else:
             self.charge_level = new_charge_level
-            self.soc = self.charge_level / self.capacity
+            self._soc = self.charge_level / self.capacity
 
         return charged_energy * 3600  # Wh to Ws
 
+    def soc(self) -> float:
+        return self._soc
+
     def state(self) -> dict:
         """Returns state information of the battery as a dict."""
         return {
-            "soc": self.soc,
+            "soc": self._soc,
             "charge_level": self.charge_level,
             "capacity": self.capacity,
             "min_soc": self.min_soc,