diff --git a/tools/SiblingKiller.py b/tools/SiblingKiller.py
index d84330db5b..50c7bed941 100644
--- a/tools/SiblingKiller.py
+++ b/tools/SiblingKiller.py
@@ -141,7 +141,7 @@ class SiblingKiller:
 
     def wait_for_server(self):
         for i in range(0, 2):
-            if self.ping(): # unsuccessful ping takes 5 seconds (look at PING_TIMEOUT) 
+            if self.ping(): # unsuccessful ping takes 5 seconds (look at PING_TIMEOUT) iff there is a dead server occupying the port
                 return True
         return False
     
@@ -162,7 +162,7 @@ class SiblingKiller:
     def serving_process_id(self):
         resp = str()
         try:
-            response = urllib2.urlopen('http://localhost:{port}/id'.format(port=PORT), timeout=self.ping_timeout);
+            response = urllib2.urlopen('http://localhost:{port}/id'.format(port=self.port), timeout=self.ping_timeout);
             resp = response.read()
             id = int(resp)
             return id
diff --git a/tools/run_desktop_tests.py b/tools/run_desktop_tests.py
index 1391d498d2..87b0ccfc6f 100755
--- a/tools/run_desktop_tests.py
+++ b/tools/run_desktop_tests.py
@@ -116,11 +116,9 @@ class TestRunner:
             
             not_found = filter(not_on_disk, self.runlist)
 
-
         # now let's move the tests that need a server either to the beginning or the end of the tests_to_run list
-
-        tests_with_server = TESTS_REQUIRING_SERVER
-        for test in tests_with_server:
+        tests_with_server = list(TESTS_REQUIRING_SERVER)
+        for test in TESTS_REQUIRING_SERVER:
             if test in tests_to_run:
                 tests_to_run.remove(test)
             else:
@@ -204,10 +202,10 @@ class TestRunner:
         results = dict()
 
         for key in to_run_and_with_server_keys:
-            if key == WITH_SERVER:
+            if key == WITH_SERVER and categorized_tests[WITH_SERVER]:
                 self.start_server()
             results = self.merge_dicts_of_lists(results, self.run_tests(categorized_tests[key]))
-            if key == WITH_SERVER:
+            if key == WITH_SERVER and categorized_tests[WITH_SERVER]:
                 self.stop_server()
 
         self.print_pretty("failed", results[FAILED])