Merge pull request #14 from StephenSmith25/fix_str_params

correct string start value

examples/demoslave.py

@@ -1,4 +1,4 @@
-from pythonfmu3 import Fmi3Causality, Fmi3Variability, Fmi3Slave, Float64
+from pythonfmu3 import Fmi3Causality, Fmi3Variability, Fmi3Slave, Float64, String
 
 
 class Resistor(Fmi3Slave):
@@ -19,6 +19,7 @@ def __init__(self, **kwargs):
         self.delta_v = 10.
         self.i = 0.001
         self.R = 10000.
+        self.stringVariable = "mine"
 
         self.register_variable(Float64("time", causality=Fmi3Causality.independent, variability=Fmi3Variability.continuous))
         self.register_variable(Float64("R", causality=Fmi3Causality.parameter, variability=Fmi3Variability.tunable))
@@ -31,6 +32,8 @@ def __init__(self, **kwargs):
         self.register_variable(Float64("delta_v", causality=Fmi3Causality.local))
         self.register_variable(Float64("i", causality=Fmi3Causality.local))
 
+        self.register_variable(String("stringVariable", causality=Fmi3Causality.parameter))
+
     def do_step(self, current_time, step_size):
         self.delta_v = self.positive_pin_v - self.negative_pin_v
         self.i = i = self.delta_v / self.R

pythonfmu3/tests/test_variables.py

@@ -295,7 +295,9 @@ def test_String_to_xml(name, start):
     r = String(name, start)
     xml = r.to_xml()
     if start is not None:
-        assert xml.attrib['start'] == str(start)
+        start_elements = xml.findall('.//Start')
+        assert len(start_elements) == 1
+        assert start_elements[0].attrib['value'] == str(start)
 
 
 @pytest.mark.requirements("numpy")  

pythonfmu3/variables.py

@@ -132,6 +132,16 @@ def __repr__(self) -> str:
                f"causality={self.causality}, " \
                f"variability={self.variability})"
 
+class Start(object):
+    def __init__(self, startValue):
+        self.value = startValue
+
+    def to_xml(self) -> Element:
+        attrib = dict()
+        attrib["value"] = self.value
+        return Element("Start", attrib)
+
+
 class Dimension(object):
     def __init__(self, start: str = "", valueReference: str = ""):
         if start and valueReference and any((start, valueReference)):
@@ -320,16 +330,17 @@ def to_xml(self) -> Element:
 class String(ModelVariable):
     def __init__(self, name: str, start: Optional[Any] = None, **kwargs):
         super().__init__(name, **kwargs)
-        self.__attrs = {"start": start}
+        self.__attrs = dict()
         self._type = "String"
+        self._start = Start(start)
 
     @property
     def start(self) -> Optional[Any]:
-        return self.__attrs["start"]
+        return self._start.value
 
     @start.setter
     def start(self, value: float):
-        self.__attrs["start"] = value
+        self._start.value = value
 
     def to_xml(self) -> Element:
         attrib = dict()
@@ -338,6 +349,9 @@ def to_xml(self) -> Element:
                 attrib[key] = str(value)
         self._extras = attrib
         parent = super().to_xml()
+
+        if self.start is not None:
+            parent.append(self._start.to_xml())
 
         return parent