[IMP] base: improve test coverage

The forbidden cases were not tested, making it harder to detect

closes odoo/odoo#36846

Signed-off-by: Martin Trigaux (mat) <mat@odoo.com>

odoo/addons/base/tests/test_base.py

@@ -7,7 +7,7 @@ from odoo import SUPERUSER_ID
 from odoo.exceptions import UserError, ValidationError
 from odoo.tests.common import TransactionCase, BaseCase
 from odoo.tools import mute_logger
-from odoo.tools.safe_eval import safe_eval, const_eval
+from odoo.tools.safe_eval import safe_eval, const_eval, expr_eval
 
 
 class TestSafeEval(BaseCase):
@@ -17,6 +17,12 @@ class TestSafeEval(BaseCase):
         actual = const_eval('(1, {"a": {2.5}}, [None, u"foo"])')
         self.assertEqual(actual, expected)
 
+    def test_expr(self):
+        # NB: True and False are names in Python 2 not consts
+        expected = 3 * 4
+        actual = expr_eval('3 * 4')
+        self.assertEqual(actual, expected)
+
     def test_01_safe_eval(self):
         """ Try a few common expressions to verify they work with safe_eval """
         expected = (1, {"a": 9 * 2}, (True, False, None))
@@ -41,10 +47,19 @@ class TestSafeEval(BaseCase):
 
     @mute_logger('odoo.tools.safe_eval')
     def test_05_safe_eval_forbiddon(self):
-        """ Try forbidden expressions in safe_eval to verify they are not allowed (open) """
+        """ Try forbidden expressions in safe_eval to verify they are not allowed"""
+        # no forbidden builtin expression
         with self.assertRaises(ValueError):
             safe_eval('open("/etc/passwd","r")')
 
+        # no forbidden opcodes
+        with self.assertRaises(ValueError):
+            safe_eval("import odoo", mode="exec")
+
+        # no dunder
+        with self.assertRaises(NameError):
+            safe_eval("self.__name__", {'self': self}, mode="exec")
+
 
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