start servers on different ports to prevent conflicts

test/support/server.tcl

@@ -22,6 +22,9 @@ proc start_server {filename overrides {code undefined}} {
     # use a different directory every time a server is started
     dict set config dir [tmpdir server]
     
+    # start every server on a different port
+    dict set config port [incr ::port]
+
     # apply overrides from arguments
     foreach override $overrides {
         set directive [lrange $override 0 0]

test/test_helper.tcl

@@ -10,7 +10,7 @@ source test/support/test.tcl
 source test/support/util.tcl
 
 set ::host 127.0.0.1
-set ::port 6379
+set ::port 16379
 set ::traceleaks 0
 
 proc execute_tests name {