Patch for BUG#15934: im_daemon_life_cycle fails sporadically.

The problem was a race condition in a test case.

The fix eliminates the race condition by explicit
wait on UNIX socket to start accepting connections.

The patch affects only test suite (i.e. does not touch
server codebase).

mysql-test/mysql-test-run.pl

@@ -1249,6 +1249,9 @@ sub environment_setup () {
   $ENV{'IM_PATH_PID'}=        $instance_manager->{path_pid};
   $ENV{'IM_PATH_ANGEL_PID'}=  $instance_manager->{path_angel_pid};
   $ENV{'IM_PORT'}=            $instance_manager->{port};
+  $ENV{'IM_PATH_SOCK'}=       $instance_manager->{path_sock};
+  $ENV{'IM_USERNAME'}=        $instance_manager->{admin_login};
+  $ENV{'IM_PASSWORD'}=        $instance_manager->{admin_password};
 
   $ENV{'IM_MYSQLD1_SOCK'}=    $instance_manager->{instances}->[0]->{path_sock};
   $ENV{'IM_MYSQLD1_PORT'}=    $instance_manager->{instances}->[0]->{port};
@@ -1257,6 +1260,9 @@ sub environment_setup () {
   $ENV{'IM_MYSQLD2_PORT'}=    $instance_manager->{instances}->[1]->{port};
   $ENV{'IM_MYSQLD2_PATH_PID'}=$instance_manager->{instances}->[1]->{path_pid};
 
+  $ENV{'EXE_MYSQL'}=          $exe_mysql;
+
+
   $ENV{MTR_BUILD_THREAD}= 0 unless $ENV{MTR_BUILD_THREAD}; # Set if not set
 
   # We are nice and report a bit about our settings

mysql-test/r/im_daemon_life_cycle.result

@@ -8,6 +8,7 @@ mysqld2	offline
 Killing the process...
 Sleeping...
 Success: the process was restarted.
+Success: server is ready to accept connection on socket.
 
 --------------------------------------------------------------------
 -- Test for BUG#12751

mysql-test/t/im_daemon_life_cycle.imtest

@@ -17,6 +17,12 @@
 
 ###########################################################################
 
+# Wait for IM to start accepting connections.
+
+--exec $MYSQL_TEST_DIR/t/wait_for_socket.sh $EXE_MYSQL $IM_PATH_SOCK $IM_USERNAME $IM_PASSWORD '' 30
+
+###########################################################################
+
 #
 # BUG#12751: Instance Manager: client hangs
 #

mysql-test/t/wait_for_socket.sh

+#!/bin/sh
+
+###########################################################################
+
+if [ $# -ne 6 ]; then
+  echo "Usage: wait_for_socket.sh <executable path> <socket path> <username> <password> <db> <timeout>"
+  exit 0
+fi
+
+client_exe="$1"
+socket_path="$2"
+username="$3"
+password="$4"
+db="$5"
+total_timeout="$6"
+
+###########################################################################
+
+if [ -z "$client_exe" ]; then
+  echo "Error: invalid path to client executable ($client_exe)."
+  exit 0;
+fi
+
+if [ ! -x "$client_exe" ]; then
+  echo "Error: client by path '$client_exe' is not available."
+  exit 0;
+fi
+
+if [ -z "$socket_path" ]; then
+  echo "Error: invalid socket patch."
+  exit 0
+fi
+
+###########################################################################
+
+client_args="--silent --socket=$socket_path "
+
+[ -n "$username" ] && client_args="$client_args --user=$username "
+[ -n "$password" ] && client_args="$client_args --password=$password "
+[ -n "$db" ] && client_args="$client_args $db"
+
+###########################################################################
+
+cur_attempt=1
+
+while true; do
+
+  if ( echo 'quit' | "$client_exe" $client_args >/dev/null 2>&1 ); then
+    echo "Success: server is ready to accept connection on socket."
+    exit 0
+  fi
+
+  [ $cur_attempt -ge $total_timeout ] && break
+
+  sleep 1
+
+  cur_attempt=`expr $cur_attempt + 1`
+
+done
+
+echo "Error: server does not accept connections after $total_timeout seconds."
+exit 0