Test: code to test server availability refactored.

Some inline test moved into server_is_up procedure.
Also find_available_port was moved into util since it is going
to be used for the Sentinel test as well.

tests/support/server.tcl

@@ -79,7 +79,7 @@ proc is_alive config {
 proc ping_server {host port} {
     set retval 0
     if {[catch {
-        set fd [socket $::host $::port]
+        set fd [socket $host $port]
         fconfigure $fd -translation binary
         puts $fd "PING\r\n"
         flush $fd
@@ -101,6 +101,22 @@ proc ping_server {host port} {
     return $retval
 }
 
+# Return 1 if the server at the specified addr is reachable by PING, otherwise
+# returns 0. Performs a try every 50 milliseconds for the specified number
+# of retries.
+proc server_is_up {host port retrynum} {
+    after 10 ;# Use a small delay to make likely a first-try success.
+    set retval 0
+    while {[incr retrynum -1]} {
+        if {[catch {ping_server $host $port} ping]} {
+            set ping 0
+        }
+        if {$ping} {return 1}
+        after 50
+    }
+    return 0
+}
+
 # doesn't really belong here, but highly coupled to code in start_server
 proc tags {tags code} {
     set ::tags [concat $::tags $tags]
@@ -191,23 +207,13 @@ proc start_server {options {code undefined}} {
     # check that the server actually started
     # ugly but tries to be as fast as possible...
     if {$::valgrind} {set retrynum 1000} else {set retrynum 100}
-    set serverisup 0
 
     if {$::verbose} {
         puts -nonewline "=== ($tags) Starting server ${::host}:${::port} "
     }
 
-    after 10
     if {$code ne "undefined"} {
-        while {[incr retrynum -1]} {
+        set serverisup [server_is_up $::host $::port $retrynum]
-            catch {
-                if {[ping_server $::host $::port]} {
-                    set serverisup 1
-                }
-            }
-            if {$serverisup} break
-            after 50
-        }
     } else {
         set serverisup 1
     }

tests/support/util.tcl

@@ -312,3 +312,18 @@ proc csvstring s {
 proc roundFloat f {
     format "%.10g" $f
 }
+
+proc find_available_port start {
+    for {set j $start} {$j < $start+1024} {incr j} {
+        if {[catch {
+            set fd [socket 127.0.0.1 $j]
+        }]} {
+            return $j
+        } else {
+            close $fd
+        }
+    }
+    if {$j == $start+1024} {
+        error "Can't find a non busy port in the $start-[expr {$start+1023}] range."
+    }
+}

tests/test_helper.tcl

@@ -164,21 +164,6 @@ proc cleanup {} {
     if {!$::quiet} {puts "OK"}
 }
 
-proc find_available_port start {
-    for {set j $start} {$j < $start+1024} {incr j} {
-        if {[catch {
-            set fd [socket 127.0.0.1 $j]
-        }]} {
-            return $j
-        } else {
-            close $fd
-        }
-    }
-    if {$j == $start+1024} {
-        error "Can't find a non busy port in the $start-[expr {$start+1023}] range."
-    }
-}
-
 proc test_server_main {} {
     cleanup
     set tclsh [info nameofexecutable]