SW-828: class variable instantation and checkig for None, so we can handle any...

SW-828: class variable instantation and checkig for None, so we can handle any exception during setup phase.

LCS/PyCommon/test/postgres.py

@@ -34,6 +34,11 @@ class PostgresTestMixin():
     It implements the unittest setUpClass/tearDownClass methods and uses them as a template method pattern to do all the testing-database setup/teardown work for you.
     '''
 
+    # class variables are initialized in setUpClass
+    _postgresql  = None
+    dbcreds      = None
+    db           = None
+
     @classmethod
     def setUpClass(cls):
         logger.info('setting up test-database instance...')
@@ -80,9 +85,10 @@ class PostgresTestMixin():
         cls.print_database_instance_log()
 
         try:
-            logger.info('removing test-database instance at %s', cls.dbcreds.stringWithHiddenPassword())
-            cls._postgresql.stop()
-            logger.info('test-database instance removed')
+            if cls._postgresql:
+                logger.info('removing test-database instance at %s', cls.dbcreds.stringWithHiddenPassword())
+                cls._postgresql.stop()
+                logger.info('test-database instance removed')
         except Exception as e:
             logger.info('error while removing test-database instance at %s: %s', cls.dbcreds.stringWithHiddenPassword(), e)
 
@@ -105,8 +111,9 @@ class PostgresTestMixin():
     def close_database_connection(cls):
         ''' close the database connection created in create_database_connection'''
         try:
-            logger.info('Closing PostgresDatabaseConnection to test-database %s...', cls.db)
-            cls.db.disconnect()
+            if cls.db:
+                logger.info('Closing PostgresDatabaseConnection to test-database %s...', cls.db)
+                cls.db.disconnect()
         except Exception as e:
             logger.error("Error while closing PostgresDatabaseConnection to test-database: %s", e)
 
@@ -114,10 +121,11 @@ class PostgresTestMixin():
     def print_database_instance_log(cls):
         '''print the log of the testing-database instance (can help debugging sql statements)'''
         try:
-            db_log_file_name = os.path.join(cls._postgresql.base_dir, '%s.log' % cls._postgresql.name)
-            logger.info('Printing test-postgress-database server log for reference: %s', db_log_file_name)
-            with open(db_log_file_name, 'r') as db_log_file:
-                for line in db_log_file.readlines():
-                    print("  postgres log: %s" % line.strip(), file=sys.stderr)
+            if cls._postgresql:
+                db_log_file_name = os.path.join(cls._postgresql.base_dir, '%s.log' % cls._postgresql.name)
+                logger.info('Printing test-postgress-database server log for reference: %s', db_log_file_name)
+                with open(db_log_file_name, 'r') as db_log_file:
+                    for line in db_log_file.readlines():
+                        print("  postgres log: %s" % line.strip(), file=sys.stderr)
         except Exception as e:
             logger.error("Error while printing test-postgress-database server log: %s", e)