if { [isdraw result] } {
   set sm 0
   if { [isdraw s] } {
      regexp {Mass +: +([-0-9.+eE]+)} [sprops s] full sm
   }
   regexp {Mass +: +([-0-9.+eE]+)} [sprops result] full m

   #check if result is valid
   puts [checkshape result]
   if { $m == 0 || $sm == $m } {
       puts "Error : The blend is not valid."
   }

   if { $square > 0 } {
      puts "The expected area is $square"
   }
   #check of change of square is < 1%
   if { ($square != 0 && [expr 1.*abs($square - $m)/$square] > 0.01) || ($square == 0 && $m != 0) } {
      puts "Error : The area of the resulting shape is $m"
   }
   if { $m > 0 } {
      clear
      smallview
      donly result
      fit
      xwd $imagedir/${test_image}.png
   }
} else {
   puts "Error : The blend cannot be built."
}

# to end a test script
puts "TEST COMPLETED"
