Weight-based shipping bands now support different method codes

oscar/apps/shipping/models.py

+from decimal import Decimal as D
 from django.db import models
 from django.utils.translation import ugettext_lazy as _
 
 
 
 class WeightBand(models.Model):
+    method_code = models.CharField(max_length=64, db_index=True)
     upper_limit = models.DecimalField(decimal_places=2, max_digits=12,
                                       help_text=_("""Enter upper limit of this weight band in Kg"""))
     charge = models.DecimalField(decimal_places=2, max_digits=12)
     
     @property
     def weight_from(self):
-        lower_bands = WeightBand.objects.filter(upper_limit__lt=self.upper_limit).order_by('-upper_limit')
+        lower_bands = WeightBand.objects.filter(method_code=self.method_code,
+                upper_limit__lt=self.upper_limit).order_by('-upper_limit')
         if not lower_bands:
             return D('0.00')
         return lower_bands[0].upper_limit
         return u'Charge for weights up to %s' % (self.upper_limit,)
         
     @classmethod
-    def get_band_for_weight(cls, weight):
+    def get_band_for_weight(cls, method_code, weight):
         """
         Return the weight band for a given weight
         """
-        bands = WeightBand.objects.filter(upper_limit__gte=weight).order_by('upper_limit')
+        bands = WeightBand.objects.filter(method_code=method_code, 
+                upper_limit__gte=weight).order_by('upper_limit')
         if not bands.count():
             # No band for this weight
             return None

oscar/apps/shipping/tests.py

         WeightBand.objects.all().delete()
 
     def test_get_band_for_lower_weight(self):
-        band = WeightBand.objects.create(upper_limit=1, charge=D('4.00'))
-        fetched_band = WeightBand.get_band_for_weight(0.5)
+        band = WeightBand.objects.create(method_code='standard', upper_limit=1, charge=D('4.00'))
+        fetched_band = WeightBand.get_band_for_weight('standard', 0.5)
         self.assertEqual(band.id, fetched_band.id)
 
     def test_get_band_for_higher_weight(self):
-        band = WeightBand.objects.create(upper_limit=1, charge=D('4.00'))
-        fetched_band = WeightBand.get_band_for_weight(1.5)
+        band = WeightBand.objects.create(method_code='standard', upper_limit=1, charge=D('4.00'))
+        fetched_band = WeightBand.get_band_for_weight('standard', 1.5)
         self.assertIsNone(fetched_band)
 
     def test_get_band_for_matching_weight(self):
-        band = WeightBand.objects.create(upper_limit=1, charge=D('4.00'))
-        fetched_band = WeightBand.get_band_for_weight(1)
+        band = WeightBand.objects.create(method_code='standard', upper_limit=1, charge=D('4.00'))
+        fetched_band = WeightBand.get_band_for_weight('standard', 1)
         self.assertEqual(band.id, fetched_band.id)
 
-    def test_get_band_for_series_of_bands(self):
+    def test_weight_to_is_upper_bound(self):
+        band = WeightBand.objects.create(method_code='standard', upper_limit=1, charge=D('4.00'))
+        self.assertEqual(1, band.weight_to)
+
+    def test_weight_from_for_single_band(self):
+        band = WeightBand.objects.create(method_code='standard', upper_limit=1, charge=D('4.00'))
+        self.assertEqual(0, band.weight_from)
+
+    def test_weight_from_for_multiple_bands(self):
         WeightBand.objects.create(upper_limit=1, charge=D('4.00'))
-        WeightBand.objects.create(upper_limit=2, charge=D('8.00'))
-        WeightBand.objects.create(upper_limit=3, charge=D('12.00'))
-        self.assertEqual(D('4.00'), WeightBand.get_band_for_weight(0.5).charge)
-        self.assertEqual(D('8.00'), WeightBand.get_band_for_weight(1.5).charge)
-        self.assertEqual(D('12.00'), WeightBand.get_band_for_weight(2.5).charge)
+        band = WeightBand.objects.create(method_code='standard', upper_limit=2, charge=D('8.00'))
+        self.assertEqual(1, band.weight_from)
+
+    def test_weight_from_for_multiple_bands(self):
+        WeightBand.objects.create(method_code='standard', upper_limit=1, charge=D('4.00'))
+        band = WeightBand.objects.create(method_code='express', upper_limit=2, charge=D('8.00'))
+        self.assertEqual(0, band.weight_from)
+
+    def test_get_band_for_series_of_bands(self):
+        WeightBand.objects.create(method_code='standard', upper_limit=1, charge=D('4.00'))
+        WeightBand.objects.create(method_code='standard', upper_limit=2, charge=D('8.00'))
+        WeightBand.objects.create(method_code='standard', upper_limit=3, charge=D('12.00'))
+        self.assertEqual(D('4.00'), WeightBand.get_band_for_weight('standard', 0.5).charge)
+        self.assertEqual(D('8.00'), WeightBand.get_band_for_weight('standard', 1.5).charge)
+        self.assertEqual(D('12.00'), WeightBand.get_band_for_weight('standard', 2.5).charge)
+
+    def test_get_band_for_series_of_bands_from_different_methods(self):
+        WeightBand.objects.create(method_code='standard', upper_limit=1, charge=D('4.00'))
+        WeightBand.objects.create(method_code='express', upper_limit=2, charge=D('8.00'))
+        WeightBand.objects.create(method_code='standard', upper_limit=3, charge=D('12.00'))
+        self.assertEqual(D('12.00'), WeightBand.get_band_for_weight('standard', 2.5).charge)