unit_test.lua

local function expect(actual)
  return {
    to_be = function(expected)
      if type(actual) ~= type(expected) then
        if type(expected) == "string" then
          expected = ([["%s"]]):format(expected)
        end
        error(("Type mismatch: (%s) (%s)"):format(tostring(expected), tostring(actual)), 2)
      end
      if actual ~= expected then
        error(("Expected (%s), got (%s)"):format(expected, tostring(actual)), 2)
      end
    end,
  }
end

function is_table_equal(t1,t2,ignore_mt)
  local ty1 = type(t1)
  local ty2 = type(t2)
  if ty1 ~= ty2 then return false end
  -- non-table types can be directly compared
  if ty1 ~= 'table' and ty2 ~= 'table' then return t1 == t2 end
  -- as well as tables which have the metamethod __eq
  local mt = getmetatable(t1)
  if not ignore_mt and mt and mt.__eq then return t1 == t2 end
  for k1,v1 in pairs(t1) do
     local v2 = t2[k1]
     if v2 == nil or not is_table_equal(v1,v2) then return false end
  end
  for k2,v2 in pairs(t2) do
     local v1 = t1[k2]
     if v1 == nil or not is_table_equal(v1,v2) then return false end
  end
  return true
end

return expect