Removed deprecated 'main' and path treatment

tests/test_account_invoice_discount.py

@@ -2,13 +2,6 @@
 # The COPYRIGHT file at the top level of this repository contains the full
 # copyright notices and license terms.
 
-import sys
-import os
-DIR = os.path.abspath(os.path.normpath(os.path.join(__file__,
-    '..', '..', '..', '..', '..', 'trytond')))
-if os.path.isdir(DIR):
-    sys.path.insert(0, os.path.dirname(DIR))
-
 import unittest
 import doctest
 import trytond.tests.test_tryton
@@ -55,6 +48,3 @@ def suite():
             setUp=doctest_dropdb, tearDown=doctest_dropdb, encoding='utf-8',
             optionflags=doctest.REPORT_ONLY_FIRST_FAILURE))
     return suite
-
-if __name__ == '__main__':
-    unittest.TextTestRunner(verbosity=2).run(suite())