[IMP] util/helpers: tests for import/export empty paths

Commits 5b944f7 and
1d9e20e did not consider the case of empty
paths, what was fixed in a05df66.
Due to its urgent nature, no tests were added with the fix's commit.

That said, this commit adds tests for the case when `base_import.mapping` or
`ir.export.line` present path fields which are empty.

src/base/tests/test_util.py

@@ -420,6 +420,7 @@ def setUp(self):
                         (0, 0, {"name": "rate_ids/company_id/user_ids/name"}),
                         (0, 0, {"name": "rate_ids/company_id/user_ids/partner_id/user_ids/name"}),
                         (0, 0, {"name": "rate_ids/name"}),
+                        (0, 0, {}),
                     ],
                 }
             ]
@@ -444,7 +445,7 @@ def test_rename_field(self):
     def test_remove_field(self):
         util.remove_field(self.cr, "res.currency.rate", "company_id")
         self._invalidate()
-        self.assertEqual(len(self.export.export_fields), 2)
+        self.assertEqual(len(self.export.export_fields), 3)
         self.assertEqual(self.export.export_fields[0].name, "full_name")
         self.assertEqual(self.export.export_fields[1].name, "rate_ids/name")
 
@@ -456,11 +457,11 @@ def test_rename_model(self):
     def test_remove_model(self):
         util.remove_model(self.cr, "res.currency.rate")
         self._invalidate()
-        self.assertEqual(len(self.export.export_fields), 1)
-        self.assertEqual(self.export.export_fields[0].name, "full_name")
+        self.assertEqual(len(self.export.export_fields), 2)
+        self.assertEqual(self.export.export_fields.mapped("name"), ["full_name", False])
 
         util.remove_model(self.cr, "res.currency")
-        self.cr.execute("SELECT * FROM ir_exports WHERE id = %s", [self.export.id])
+        self.cr.execute("SELECT * FROM ir_exports WHERE id IN %s", [tuple(self.export.ids)])
         self.assertFalse(self.cr.fetchall())
 
 
@@ -478,6 +479,9 @@ def setUp(self):
                 ]
             ]
         )
+        self.import_mapping = self.import_mapping + self.env["base_import.mapping"].create(
+            {"res_model": "res.currency", "column_name": "Column name"}
+        )
 
         util.flush(self.import_mapping)
 
@@ -523,10 +527,10 @@ def test_remove_model(self):
         remaining_mappings = self.import_mapping - removed_mappings
 
         self.assertEqual(len(removed_mappings), 3)
-        self.assertEqual(remaining_mappings[0].field_name, "full_name")
+        self.assertEqual(remaining_mappings.mapped("field_name"), ["full_name", False])
 
         util.remove_model(self.cr, "res.currency")
-        self.cr.execute("SELECT * FROM base_import_mapping WHERE id = %s", [remaining_mappings.id])
+        self.cr.execute("SELECT * FROM base_import_mapping WHERE id IN %s", [tuple(remaining_mappings.ids)])
         self.assertFalse(self.cr.fetchall())