fix postfix test, fixes #20388

tests/test_postfix.py

@@ -4,34 +4,17 @@
 Check that emails can be sent.
 '''
 import os
-import re
 import subprocess
 import sys
 
 
 if not os.path.exists('/etc/postfix'):
     print('Postfix dir does not exists, test skipped.')
+    sys.exit(1)
 else:
     # check that postfix listens the port 25 correctly
-    out = subprocess.check_output('netstat -pant | grep \':25\'', shell=True)
-    out = out.decode('utf-8') if out else ''
-
-    # netstat -pant output columns are:
-    # Proto | Recv-Q | Send-Q | Local address | Foreign address | State | PID/Program name
-
-    expected = r'tcp +\d +\d +127\.0\.0\.1:25 +0\.0\.0\.0:\* +LISTEN +[\d]+/master'
-    found = False
-    if out:
-        for line in out.split('\n'):
-            line = re.sub(r' +', ' ', line)
-            if line:
-                if not re.match(expected, line):
-                    print('Unexpected result for postfix listening ports:\n%s' % line)
-                    sys.exit(1)
-                else:
-                    found = True
-
-    if not found:
+    status, out = subprocess.getstatusoutput('netstat -pant | grep master | grep 127.0.0.1:25', shell=True)
+    if status != 0:
         print('The port 25 is not listened by any process.')
         sys.exit(1)
     print('Postfix listening port: OK.')