TMSS-142: added cmdline option to provide preffered django port

SAS/TMSS/test/test_utils.py

@@ -230,12 +230,12 @@ class TMSSDjangoServerInstance():
 
 class TMSSTestEnvironment:
     '''Create and run a test django TMSS server against a newly created test database and a test ldap server (and cleanup automagically)'''
-    def __init__(self):
+    def __init__(self, preferred_django_port: int=8000):
         self.ldap_server = TestLDAPServer(user='test', password='test')
         self.database = TMSSTestDatabaseInstance()
         self.django_server = TMSSDjangoServerInstance(db_dbcreds_id=self.database.dbcreds_id,
                                                       ldap_dbcreds_id=self.ldap_server.dbcreds_id,
-                                                      port=find_free_port(8000))
+                                                      port=find_free_port(preferred_django_port))
 
     def start(self):
         self.ldap_server.start()
@@ -288,10 +288,18 @@ def main_test_database():
 
 def main_test_environment():
     """instantiate, run and destroy a full tmss test environment (postgress database, ldap server, django server)"""
+    from optparse import OptionParser
     os.environ['TZ'] = 'UTC'
+
+    parser = OptionParser('%prog [options]',
+                          description='setup/run/teardown a full TMSS test environment including a fresh and isolated database, LDAP server and DJANGO REST server.')
+    parser.add_option("-p", "--port", dest="port", type="int", default=find_free_port(8000),
+                      help="try to use this port for the DJANGO REST API. If not available, then a random free port is used and logged. [default=%default]")
+    (options, args) = parser.parse_args()
+
     logging.basicConfig(format = '%(asctime)s %(levelname)s %(message)s', level = logging.INFO)
 
-    with TMSSTestEnvironment() as instance:
+    with TMSSTestEnvironment(preferred_django_port=options.port) as instance:
         # print some nice info for the user to use the test servers...
         # use print instead of log for clean lines.
         for h in logging.root.handlers: