[IMP] test_lint: add a test to detect git conflict markers

Since the deployement of the forward-port bot, chances to merge code
with conflict markers has greatly increased.

With this commit, a new test is added to grep for those markers in most
common code files.

closes odoo/odoo#39984

X-original-commit: 80f22f98
Signed-off-by: Christophe Monniez (moc) <moc@odoo.com>

odoo/addons/test_lint/tests/__init__.py

 from . import test_pylint
 from . import test_ecmascript
+from . import test_markers

odoo/addons/test_lint/tests/test_markers.py

+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+import logging
+import os
+import odoo
+from odoo.tests.common import TransactionCase
+from odoo.modules.module import ad_paths
+
+_logger = logging.getLogger(__name__)
+MARKERS = [b'<' * 7, b'>' * 7]
+EXTENSIONS = ('.py', '.js', '.xml', '.less', '.sass')
+
+
+class TestConflictMarkers(TransactionCase):
+
+    def check_file(self, fullpath_name):
+
+        with open(fullpath_name, 'rb') as f:
+            content = f.read()
+            self.assertFalse(any([m in content for m in MARKERS]), 'Conflict markers found in %s' % fullpath_name)
+
+    def test_conflict_markers(self):
+        """ Test that there are no conflict markers left in Odoo files """
+
+        counter = 0
+
+        odoo_path = os.path.dirname(odoo.__file__)
+        paths = ad_paths + [odoo_path]
+        paths.remove(os.path.join(odoo_path, 'addons'))  # avoid checking odoo/addons twice
+
+        for p in paths:
+            for dp, _, file_names in os.walk(p):
+                for fn in file_names:
+                    if fn.endswith(EXTENSIONS):
+                        self.check_file(os.path.join(dp, fn))
+                        counter += 1
+        _logger.info('%s files tested', counter)