update to add check to make sure phases have fully assigned molefractions during initialisation.

phasecalculator/classes/phase.py

@@ -55,6 +55,8 @@ class Phase(object):
         """
         self.molecule_list = molecule_list
         self.temperature = temperature
+        if not self.total_molefraction_is_one():
+            raise ValueError("Total molefractions of phase not equal to one")
 
     def __eq__(self, other):
         """Overload equality comparison operator.
@@ -146,6 +148,20 @@ class Phase(object):
         """
         return Temperature.parse_xml(temperature_xml)
 
+    def total_molefraction_is_one(self):
+        """Calculate total molefraction of the molecule and check this is 1.0.
+
+        Returns
+        -------
+        bool
+            True if total molefraction of components is one.
+
+        """
+        molefraction_total = 0.0
+        for mole_frac in self.get_molefractions_by_molecule().values():
+            molefraction_total += mole_frac
+        return (abs(1.0-molefraction_total) < 1e-5)
+
     def write_to_xml(self):
         """Write information to Etree representation of XML.