Ensure that n=# key-value pair is before all other key-value pairs in…

… canonical ordering

setup.py

@@ -8,7 +8,7 @@
 
 setup(
     name="pyvalem",
-    version="2.5.6",
+    version="2.5.7",
     description="A package for managing simple chemical species and states",
     long_description=long_description,
     long_description_content_type="text/x-rst",

src/pyvalem/stateful_species.py

@@ -38,7 +38,7 @@ def __repr__(self):
         """Return a canonical text representation of the StatefulSpecies."""
         if self.states:
             states_sorted = sorted(
-                self.states, key=lambda state: (STATES[type(state)], repr(state))
+                self.states, key=lambda state: (STATES[type(state)], state.ordering)
             )
             return "{} {}".format(
                 self.formula, ";".join(repr(state) for state in states_sorted)

src/pyvalem/states/_base_state.py

@@ -66,3 +66,7 @@ def __ne__(self, other):
 
     def __hash__(self):
         return hash(self.__repr__())
+
+    @property
+    def ordering(self):
+        return repr(self)

src/pyvalem/states/key_value_pair.py

@@ -51,3 +51,9 @@ def _parse_state(self, state_str):
 
     def __repr__(self):
         return self.state_str
+
+    @property
+    def ordering(self):
+        if self.key == "n":
+            return 0
+        return ord(self.key)

tests/test_stateful_species.py

@@ -94,14 +94,18 @@ def test_stateful_species_repr(self):
         ss2 = StatefulSpecies("(235U) l=0;***;n=1")
         ss3 = StatefulSpecies("(235U) l=0;n=1;***")
         self.assertEqual(repr(ss2), repr(ss3))
-        self.assertEqual(repr(ss2), "(235U) 3*;l=0;n=1")
+        self.assertEqual(repr(ss2), "(235U) 3*;n=1;l=0")
 
         for ss_text in ["C+ 4P;2s2.2p1", "C+ 2s2.2p1;4P"]:
             self.assertEqual(repr(StatefulSpecies(ss_text)), "C+ 2s2.2p;4P")
 
         for ss_text in ["C+ 2P;2s2.2p1", "C+ 2s2.2p1;2P"]:
             self.assertEqual(repr(StatefulSpecies(ss_text)), "C+ 2s2.2p;2P")
 
+    def test_stateful_species_key_value_pair_ordering(self):
+        ss1 = StatefulSpecies("H n=3;l=1")
+        self.assertEqual(repr(ss1), "H n=3;l=1")
+
 
 if __name__ == "__main__":
     unittest.main()