fix: add extra config to make Unit model hashable

filip/models/ngsi_v2/units.py

@@ -136,6 +136,8 @@ class Unit(BaseModel):
     class Config:
         extra = 'ignore'
         allow_population_by_field_name = True
+        allow_mutation = False
+        frozen = True
 
     @root_validator(pre=False, allow_reuse=True)
     def check_consistency(cls, values):
@@ -203,6 +205,7 @@ def __getattr__(self, item):
         Return unit as attribute by name or code.
         Notes:
             Underscores will be substituted with whitespaces
+
         Args:
             item: if len(row) == 0:
 
@@ -221,7 +224,7 @@ def quantities(self):
         """
         raise NotImplementedError("The used dataset does currently not "
                                   "contain the information about quantity")
-
+    @lru_cache()
     def __getitem__(self, item: str) -> Unit:
         """
         Get unit by name or code

tests/models/test_units.py

@@ -1,7 +1,8 @@
 """
 Test for filip.models.units
 """
-from unittest import TestCase
+import unittest
+import functools
 from filip.models.ngsi_v2.units import \
     Unit, \
     Units, \
@@ -10,7 +11,7 @@
     load_units
 
 
-class TestUnitCodes(TestCase):
+class TestUnitCodes(unittest.TestCase):
 
     def setUp(self):
         self.units_data = load_units()
@@ -39,13 +40,43 @@ def test_unit_text(self):
     def test_unit_model(self):
         """
         Test unit model
+
         Returns:
             None
         """
+        # test creation
         unit = Unit(**self.unit)
         unit_from_json = Unit.parse_raw(unit.json(by_alias=True))
         self.assertEqual(unit, unit_from_json)
 
+    def test_unit_model_caching(self):
+        """
+        Test caching of unit model
+
+        Returns:
+            None
+        """
+
+        unit = Unit(**self.unit)
+        # testing hashing and caching
+        from functools import lru_cache
+        from time import perf_counter_ns
+
+        self.assertEqual(unit.__hash__(), unit.__hash__())
+
+        @functools.lru_cache
+        def cache_unit(unit: Unit):
+            return Unit(name=unit.name)
+
+        timers = []
+        for i in range(5):
+            start = perf_counter_ns()
+            cache_unit(unit)
+            stop = perf_counter_ns()
+            timers.append(stop - start)
+            if i > 0:
+                self.assertLess(timers[i], timers[0])
+
     def test_units(self):
         """
         Test units api
@@ -78,8 +109,29 @@ def test_unit_validator(self):
         Returns:
             None
         """
+
         unit_data = self.unit.copy()
         unit_data['name'] = "celcius"
         with self.assertRaises(ValueError):
             Unit(**unit_data)
 
+    def tearDown(self):
+        """
+        clean up
+        """
+        # using garbage collector to clean up all caches
+        import gc
+        gc.collect()
+
+        # All objects collected
+        objects = [i for i in gc.get_objects()
+                   if isinstance(i, functools._lru_cache_wrapper)]
+
+        # All objects cleared
+        for object in objects:
+            object.cache_clear()
+
+if __name__ == '__main__':
+    unittest.main()
+
+