-- functions to validate check better.

-- All methods have an optional level parameter, which represent which
-- level of stack to report the error (1 == the caller).  If you create
-- a check method using those, remember to pass level+1 to it, so that
-- the error is reported on the right function.

-- raise an error if cond is false, including where the error happen.
function check(cond, msg, level)
   msg = msg or "Check failed"
   level = level or 1
   if not cond then
      error(msg, level + 1)
   end
end

-- test utility to assert that two tables are equals
function check_tables(t1, t2, level)
   level = level or 1
   check(type(t1) == "table", "t1 is not a table", level + 1)
   check(type(t2) == "table", "t2 is not a table", level + 1)
   check(table.getn(t1) == table.getn(t2), "Not the same size", level + 1)
   for k,v in pairs(t1) do
      if type(v) == "table" then
         compare_tables(v, t2[k], level + 1)
      else
         check(v == t2[k], "different value", level + 1)
      end
   end
   return true
end

IGNORED = {}

-- compare two tables but ignored field from expected marked
-- as IGNORED.
function check_partial_tables(expected, result, level)
   level = level or 1
   for k, v in pairs(expected) do
      vres = result[k]
      check(vres, "invalid key", level + 1)
      if v ~= IGNORED then
         if type(v) == "table" then
            check_partial_tables(v, vres, level + 1)
         else
            check(v == vres, "different values", level + 1)
         end
      end
   end
end