Enforce strictly positive rounding value for currency

Closes #13600

modules/currency/currency.py

@@ -56,6 +56,9 @@ class Currency(
         help="Add floating exchange rates for the currency.")
     rounding = fields.Numeric('Rounding factor', required=True,
         digits=(12, Eval('digits', 6)),
+        domain=[
+            ('rounding', '>', 0),
+            ],
         help="The minimum amount which can be represented in this currency.")
     digits = fields.Integer("Digits", required=True,
         help="The number of digits to display after the decimal separator.")

modules/currency/tests/test_module.py

@@ -118,29 +118,6 @@ class CurrencyTestCase(ModuleTestCase):
 
         self.assertEqual(rounded, Decimal('1E50'))
 
-    @with_transaction()
-    def test_round_negative(self):
-        "Test rounding with negative rounding"
-        cu = create_currency('cu')
-        cu.rounding = -Decimal('0.1')
-        cu.digits = 1
-        cu.save()
-
-        rounded = cu.round(Decimal('1.23'))
-
-        self.assertEqual(rounded, Decimal('1.2'))
-
-    @with_transaction()
-    def test_round_zero(self):
-        "Test rounding with 0 as rounding"
-        cu = create_currency('cu')
-        cu.rounding = Decimal('0')
-        cu.save()
-
-        rounded = cu.round(Decimal('1.2345'))
-
-        self.assertEqual(rounded, Decimal('1.2345'))
-
     @with_transaction()
     def test_round_opposite(self):
         "Test the opposite rounding"
@@ -183,43 +160,6 @@ class CurrencyTestCase(ModuleTestCase):
             with self.subTest(value=-value):
                 self.assertEqual(cu.is_zero(-value), result)
 
-    @with_transaction()
-    def test_is_zero_negative(self):
-        "Test is zero with negative rounding"
-        cu = create_currency('cu')
-        cu.rounding = Decimal('-0.001')
-        cu.digits = 3
-        cu.save()
-
-        for value, result in [
-                (Decimal('0'), True),
-                (Decimal('0.0002'), True),
-                (Decimal('0.0009'), False),
-                (Decimal('0.002'), False),
-                ]:
-            with self.subTest(value=value):
-                self.assertEqual(cu.is_zero(value), result)
-            with self.subTest(value=-value):
-                self.assertEqual(cu.is_zero(-value), result)
-
-    @with_transaction()
-    def test_is_zero_zero(self):
-        "Test is zero with 0 as rounding"
-        cu = create_currency('cu')
-        cu.rounding = Decimal('0')
-        cu.save()
-
-        for value, result in [
-                (Decimal('0'), True),
-                (Decimal('0.0002'), False),
-                (Decimal('0.0009'), False),
-                (Decimal('0.002'), False),
-                ]:
-            with self.subTest(value=value):
-                self.assertEqual(cu.is_zero(value), result)
-            with self.subTest(value=-value):
-                self.assertEqual(cu.is_zero(-value), result)
-
     @with_transaction()
     def test_compute_simple(self):
         'Simple conversion'