[FIX] account: fix rounding error in is_valid_balance_start check

Field is_valid_balance_check is used to display a warning in case
starting balance of a bank statement is not the same as ending balance
of the previous statement. However the check was done without rounding
resulting in some error in the following casse:
starting_balance = 10.00000001
previous_ending_balance = 10

X-original-commit: 6673d23cfdee97b1e5e6368bc527a9a784578977

addons/account/models/account_bank_statement.py

@@ -201,7 +201,7 @@ class AccountBankStatement(models.Model):
     @api.depends('balance_start', 'previous_statement_id')
     def _compute_is_valid_balance_start(self):
         for bnk in self:
-            bnk.is_valid_balance_start = bnk.balance_start == bnk.previous_statement_id.balance_end_real
+            bnk.is_valid_balance_start = float_is_zero(bnk.balance_start - bnk.previous_statement_id.balance_end_real, precision_digits=bnk.currency_id.decimal_places)
 
     @api.depends('date', 'journal_id')
     def _get_previous_statement(self):

addons/account/tests/test_account_bank_statement.py

@@ -191,6 +191,14 @@ class TestBankStatement(AccountTestCommon):
         self.assertEqual(cash2.balance_start, 200)
         self.assertEqual(cash2.balance_end_real, 1000)
 
+    def test_is_valid_balance_start(self):
+        bnk1 = self.create_bank_statement('2019-01-01', 100, 100.0000001)
+        bnk2 = self.create_bank_statement('2019-01-10', 50)
+        bnk2.write({'balance_start': 100})
+        self.assertTrue(bnk2.is_valid_balance_start)
+        bnk2.write({'balance_start': 100.01})
+        self.assertFalse(bnk2.is_valid_balance_start)
+
     def test_unlink_bank_statement(self):
         bnk1 = self.create_bank_statement('2019-01-02', 100)
         bnk2 = self.create_bank_statement('2019-01-10', 50)