gis: Fixed DecimalField verification in LayerMapping.

git-svn-id: http://code.djangoproject.com/svn/django/branches/gis@6708 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/gis/tests/layermap/models.py

@@ -10,7 +10,7 @@ class City(models.Model):
 
 class Interstate(models.Model):
     name = models.CharField(max_length=20)
-    length = models.DecimalField(max_digits=7, decimal_places=2)
+    length = models.DecimalField(max_digits=6, decimal_places=2)
     path = models.LineStringField()
     objects = models.GeoManager()
     

django/contrib/gis/tests/layermap/tests.py

@@ -88,14 +88,24 @@ class LayerMapTest(unittest.TestCase):
         lm = LayerMapping(Interstate, inter_shp, inter_mapping, silent=True)
         lm.save()
 
-        # Only one interstate should have imported correctly.
-        self.assertEqual(1, Interstate.objects.count())
+        # Two interstate should have imported correctly.
+        self.assertEqual(2, Interstate.objects.count())
         
-        # Verifying the values in the single feature w/the model.
+        # Verifying the values in the layer w/the model.
         ds = DataSource(inter_shp)
-        feat = ds[0][0]
+
+        # Only the first two features of this shapefile are valid.
+        valid_feats = ds[0][:2]
+        for feat in valid_feats:
             istate = Interstate.objects.get(name=feat['Name'].value)
+            
+            if feat.fid == 0:
                 self.assertEqual(Decimal(str(feat['Length'])), istate.length)
+            elif feat.fid == 1:
+                # Everything but the first two decimal digits were truncated,
+                # because the Interstate model's `length` field has decimal_places=2.
+                self.assertAlmostEqual(feat.get('Length'), float(istate.length), 2)
+
             for p1, p2 in zip(feat.geom, istate.path):
                 self.assertAlmostEqual(p1[0], p2[0], 6)
                 self.assertAlmostEqual(p1[1], p2[1], 6)

django/contrib/gis/utils/layermapping.py

@@ -394,11 +394,27 @@ class LayerMapping(object):
                 d = Decimal(str(fld.value))
             except:
                 raise InvalidDecimal('Could not construct decimal from: %s' % fld)
+
+            # Getting the decimal value as a tuple.
             dtup = d.as_tuple()
-            if len(dtup[1]) > field_class.max_digits:
-                raise InvalidDecimal('More than the maximum # of digits encountered.')
-            elif len(dtup[1][dtup[2]:]) > field_class.decimal_places:
-                raise InvalidDecimal('More than the maximum # of decimal places encountered.')
+            digits = dtup[1]
+            d_idx = dtup[2] # index where the decimal is
+
+            # Maximum amount of precision, or digits to the left of the decimal.
+            max_prec = field_class.max_digits - field_class.decimal_places
+
+            # Getting the digits to the left of the decimal place for the 
+            # given decimal.
+            if d_idx < 0:
+                n_prec = len(digits[:d_idx])
+            else:
+                n_prec = len(digits) + d_idx
+
+            # If we have more than the maximum digits allowed, then throw an 
+            # InvalidDecimal exception.
+            if n_prec > max_prec:
+                raise InvalidDecimal('A DecimalField with max_digits %d, decimal_places %d must round to an absolute value less than 10^%d.' %
+                                     (field_class.max_digits, field_class.decimal_places, max_prec))
             val = d
         else:
             val = fld.value
@@ -467,7 +483,7 @@ class LayerMapping(object):
                     elif not self.silent: 
                         print 'Ignoring Feature ID %s because: %s' % (feat.fid, msg)
                 else:
-                    # Constructing the model using the constructed keyword args
+                    # Constructing the model using the keyword args
                     if all_prepped:
                         m = self.model(**kwargs)
                         try: