[FIX] tools: float_round DOWN

The result of the following:
```
float_round(2.5, precision_rounding=0.05, rounding_method='DOWN')
```
is 2.45. Instead, 2.5 is expected.

In case of the `DOWN` method, epsilon should be added, not subtracted.
In the meantime, we introduce a slight reorganization of the method to
make it clearer.

opw-805008

1 files changed, 16 insertions, 2 deletions

diff --git a/odoo/addons/base/tests/test_float.py b/odoo/addons/base/tests/test_float.py
index 725ba48365b..6dc1cda0550 100644
--- a/odoo/addons/base/tests/test_float.py
+++ b/odoo/addons/base/tests/test_float.py
@@ -92,6 +92,18 @@ class TestFloatPrecision(TransactionCase):
         try_round(1.8, '2', 0, method='UP')
         try_round(-1.8, '-2', 0, method='UP')
 
+        # Try some rounding value with rounding method DOWN instead of HALF-UP
+        # We use 2.425 because when normalizing 2.425 with precision_digits=3 it gives
+        # us 2424.9999999999995 as value, and if not handle correctly the rounding DOWN
+        # value will be incorrect (should be 2.425 and not 2.424)
+        try_round(2.425, '2.425', method='DOWN')
+        try_round(2.4249, '2.424', method='DOWN')
+        try_round(-2.425, '-2.425', method='DOWN')
+        try_round(-2.4249, '-2.424', method='DOWN')
+        try_round(-2.500, '-2.500', method='DOWN')
+        try_round(1.8, '1', 0, method='DOWN')
+        try_round(-1.8, '-1', 0, method='DOWN')
+
         # Extended float range test, inspired by Cloves Almeida's test on bug #882036.
         fractions = [.0, .015, .01499, .675, .67499, .4555, .4555, .45555]
         expecteds = ['.00', '.02', '.01', '.68', '.67', '.46', '.456', '.4556']
@@ -135,8 +147,8 @@ class TestFloatPrecision(TransactionCase):
         try_compare(-657.4444, -657.445, 1)
 
         # Rounding to unusual rounding units (e.g. coin values)
-        def try_round(amount, expected, precision_rounding=None):
-            value = float_round(amount, precision_rounding=precision_rounding)
+        def try_round(amount, expected, precision_rounding=None, method='HALF-UP'):
+            value = float_round(amount, precision_rounding=precision_rounding, rounding_method=method)
             result = float_repr(value, precision_digits=2)
             self.assertEqual(result, expected, 'Rounding error: got %s, expected %s' % (result, expected))
 
@@ -145,6 +157,8 @@ class TestFloatPrecision(TransactionCase):
         try_round(457.3, '455.00', precision_rounding=5)
         try_round(457.5, '460.00', precision_rounding=5)
         try_round(457.1, '456.00', precision_rounding=3)
+        try_round(2.5, '2.50', precision_rounding=0.05, method='DOWN')
+        try_round(-2.5, '-2.50', precision_rounding=0.05, method='DOWN')
 
     def test_rounding_04(self):
         """ check that proper rounding is performed for float persistence """