improved unit conversion and tests

cookbook/helper/unit_conversion_helper.py

@@ -1,18 +1,9 @@
 from django.core.cache import caches
 from decimal import Decimal
 
-
 from cookbook.helper.cache_helper import CacheHelper
 from cookbook.models import Ingredient, Unit
 
-# basic units that should be considered for "to" conversions
-# TODO possible remove this hardcoded units and just add a flag to the unit
-CONVERT_TO_UNITS = {
-    'metric': ['g', 'kg', 'ml', 'l'],
-    'us': ['ounce', 'pound', 'fluid_ounce', 'pint', 'quart', 'gallon'],
-    'uk': ['ounce', 'pound', 'imperial_fluid_ounce', 'imperial_pint', 'imperial_quart', 'imperial_gallon'],
-}
-
 CONVERSION_TABLE = {
     'weight': {
         'g': 1000,
@@ -38,8 +29,8 @@ CONVERSION_TABLE = {
     },
 }
 
-BASE_UNITS_WEIGHT = CONVERSION_TABLE['weight'].keys()
+BASE_UNITS_WEIGHT = list(CONVERSION_TABLE['weight'].keys())
-BASE_UNITS_VOLUME = CONVERSION_TABLE['volume'].keys()
+BASE_UNITS_VOLUME = list(CONVERSION_TABLE['volume'].keys())
 
 
 class ConversionException(Exception):
@@ -58,6 +49,13 @@ class UnitConversionHelper:
 
     @staticmethod
     def convert_from_to(from_unit, to_unit, amount):
+        """
+        Convert from one base unit to another. Throws ConversionException if trying to convert between different systems (weight/volume) or if units are not supported.
+        :param from_unit: str unit to convert from
+        :param to_unit: str unit to convert to
+        :param amount: amount to convert
+        :return: Decimal converted amount
+        """
         system = None
         if from_unit in BASE_UNITS_WEIGHT and to_unit in BASE_UNITS_WEIGHT:
             system = 'weight'
@@ -87,7 +85,7 @@ class UnitConversionHelper:
                 # TODO allow setting which units to convert to? possibly only once conversions become visible
                 units = caches['default'].get(CacheHelper(self.space).BASE_UNITS_CACHE_KEY, None)
                 if not units:
-                    units = Unit.objects.filter(space=self.space, base_unit__in=(CONVERT_TO_UNITS['metric'] + CONVERT_TO_UNITS['us'] + CONVERT_TO_UNITS['uk'])).all()
+                    units = Unit.objects.filter(space=self.space, base_unit__in=(BASE_UNITS_VOLUME + BASE_UNITS_WEIGHT)).all()
                     caches['default'].set(CacheHelper(self.space).BASE_UNITS_CACHE_KEY, units, 60 * 60)  # cache is cleared on unit save signal so long duration is fine
 
                 for u in units:
@@ -112,10 +110,12 @@ class UnitConversionHelper:
         conversions = [ingredient]
         if ingredient.unit:
             for c in ingredient.unit.unit_conversion_base_relation.all():
+                if c.space == self.space:
                     r = self._uc_convert(c, ingredient.amount, ingredient.unit, ingredient.food)
                     if r and r not in conversions:
                         conversions.append(r)
             for c in ingredient.unit.unit_conversion_converted_relation.all():
+                if c.space == self.space:
                     r = self._uc_convert(c, ingredient.amount, ingredient.unit, ingredient.food)
                     if r and r not in conversions:
                         conversions.append(r)

cookbook/tests/other/test_unit_conversion.py

@@ -3,15 +3,29 @@ from _decimal import Decimal
 from django.contrib import auth
 from django_scopes import scopes_disabled
 
-from cookbook.helper.unit_conversion_helper import UnitConversionHelper
+from cookbook.helper.unit_conversion_helper import UnitConversionHelper, ConversionException
 from cookbook.models import Unit, Food, Ingredient, UnitConversion
 
 
 def test_base_converter(space_1):
     uch = UnitConversionHelper(space_1)
-    assert uch.convert_from_to('g', 'kg', 1234) == 1.234
+    assert abs(uch.convert_from_to('g', 'kg', 1234) - Decimal(1.234)) < 0.0001
-    assert uch.convert_from_to('kg', 'pound', 2) == 4.40924
+    assert abs(uch.convert_from_to('kg', 'pound', 2) - Decimal(4.40924)) < 0.00001
-    # TODO add some more tests and test exception
+    assert abs(uch.convert_from_to('kg', 'g', 1) - Decimal(1000)) < 0.00001
+    assert abs(uch.convert_from_to('imperial_gallon', 'gallon', 1000) - Decimal(1200.95104)) < 0.00001
+    assert abs(uch.convert_from_to('tbsp', 'ml', 20) - Decimal(295.73549)) < 0.00001
+
+    try:
+        assert uch.convert_from_to('kg', 'tbsp', 2) == 1234
+        assert False
+    except ConversionException:
+        assert True
+
+    try:
+        assert uch.convert_from_to('kg', 'g2', 2) == 1234
+        assert False
+    except ConversionException:
+        assert True
 
 
 def test_unit_conversions(space_1, space_2, u1_s1):
@@ -41,7 +55,7 @@ def test_unit_conversions(space_1, space_2, u1_s1):
         print(conversions)
         assert len(conversions) == 2
         assert next(x for x in conversions if x.unit == unit_kg) is not None
-        assert next(x for x in conversions if x.unit == unit_kg).amount == 0.1
+        assert abs(next(x for x in conversions if x.unit == unit_kg).amount - Decimal(0.1)) < 0.0001
 
         print('\n----------- TEST BASE CONVERSIONS - VOLUMES ---------------')
 
@@ -55,7 +69,7 @@ def test_unit_conversions(space_1, space_2, u1_s1):
         conversions = uch.get_conversions(ingredient_food_1_floz1)
         assert len(conversions) == 2
         assert next(x for x in conversions if x.unit == unit_floz2) is not None
-        assert next(x for x in conversions if x.unit == unit_floz2).amount == 96.07599404038842  # TODO validate value
+        assert abs(next(x for x in conversions if x.unit == unit_floz2).amount - Decimal(96.07599404038842)) < 0.001  # TODO validate value
 
         print(conversions)
 
@@ -63,7 +77,7 @@ def test_unit_conversions(space_1, space_2, u1_s1):
         conversions = uch.get_conversions(ingredient_food_1_floz1)
         assert len(conversions) == 3
         assert next(x for x in conversions if x.unit == unit_pint) is not None
-        assert next(x for x in conversions if x.unit == unit_pint).amount == 6.004749627524276  # TODO validate value
+        assert abs(next(x for x in conversions if x.unit == unit_pint).amount - Decimal(6.004749627524276)) < 0.001  # TODO validate value
 
         print(conversions)
 
@@ -80,7 +94,7 @@ def test_unit_conversions(space_1, space_2, u1_s1):
 
         assert len(conversions) == 3
         assert next(x for x in conversions if x.unit == unit_fantasy) is not None
-        assert next(x for x in conversions if x.unit == unit_fantasy).amount == Decimal('133.700')  # TODO validate value
+        assert abs(next(x for x in conversions if x.unit == unit_fantasy).amount - Decimal('133.700')) < 0.001  # TODO validate value
 
         print(conversions)
 
@@ -117,8 +131,8 @@ def test_unit_conversions(space_1, space_2, u1_s1):
 
         conversions = uch.get_conversions(ingredient_food_1_pcs)
         assert len(conversions) == 3
-        assert next(x for x in conversions if x.unit == unit_gram).amount == 1000
+        assert abs(next(x for x in conversions if x.unit == unit_gram).amount - Decimal(1000)) < 0.0001
-        assert next(x for x in conversions if x.unit == unit_kg).amount == 1
+        assert abs(next(x for x in conversions if x.unit == unit_kg).amount - Decimal(1)) < 0.0001
         print(conversions)
 
         assert len(uch.get_conversions(ingredient_food_2_pcs)) == 1
@@ -137,19 +151,20 @@ def test_unit_conversions(space_1, space_2, u1_s1):
 
         conversions = uch.get_conversions(ingredient_food_1_pcs)
         assert len(conversions) == 3
-        assert next(x for x in conversions if x.unit == unit_gram).amount == 1000
+        assert abs(next(x for x in conversions if x.unit == unit_gram).amount - Decimal(1000)) < 0.0001
-        assert next(x for x in conversions if x.unit == unit_kg).amount == 1
+        assert abs(next(x for x in conversions if x.unit == unit_kg).amount - Decimal(1)) < 0.0001
         print(conversions)
 
         conversions = uch.get_conversions(ingredient_food_2_pcs)
         assert len(conversions) == 3
-        assert next(x for x in conversions if x.unit == unit_gram).amount == 1000
+        assert abs(next(x for x in conversions if x.unit == unit_gram).amount - Decimal(1000)) < 0.0001
-        assert next(x for x in conversions if x.unit == unit_kg).amount == 1
+        assert abs(next(x for x in conversions if x.unit == unit_kg).amount - Decimal(1)) < 0.0001
         print(conversions)
 
         print('\n----------- TEST SPACE SEPARATION ---------------')
         uc2.space = space_2
         uc2.save()
+
         conversions = uch.get_conversions(ingredient_food_2_pcs)
         assert len(conversions) == 1
         print(conversions)
@@ -164,5 +179,5 @@ def test_unit_conversions(space_1, space_2, u1_s1):
         assert len(conversions) == 2
         assert not any(x for x in conversions if x.unit == unit_kg)
         assert next(x for x in conversions if x.unit == unit_kg_space_2) is not None
-        assert next(x for x in conversions if x.unit == unit_kg_space_2).amount == 0.1
+        assert abs(next(x for x in conversions if x.unit == unit_kg_space_2).amount - Decimal(0.1)) < 0.0001
         print(conversions)