-- Some primitives for tests.

function run_tests()
  local sorted_names = {}
  for name,binding in pairs(_G) do
    if name:find('test_') == 1 then
      table.insert(sorted_names, name)
    end
  end
  table.sort(sorted_names)
  Test_errors = {}
  for _,name in ipairs(sorted_names) do
    xpcall(_G[name], function(err) prepend_debug_info_to_test_failure(name, err) end)
  end
  if #Test_errors > 0 then
    error(('There were %d test failures:\n%s'):format(#Test_errors, table.concat(Test_errors)))
  end
end

function prepend_debug_info_to_test_failure(test_name, err)
  local err_without_line_number = err:gsub('^[^:]*:[^:]*: ', '')
  local stack_trace = debug.traceback('', --[[stack frame]]5)  -- most likely to be useful, but set to 0 for a complete stack trace
  local file_and_line_number = stack_trace:gsub('stack traceback:\n', ''):gsub(': .*', '')
  local full_error = file_and_line_number..':'..test_name..' -- '..err_without_line_number
  -- uncomment this line for a complete stack trace
--?   local full_error = file_and_line_number..':'..test_name..' -- '..err_without_line_number..'\t\t'..stack_trace:gsub('\n', '\n\t\t')
  table.insert(Test_errors, full_error)
end


function check(x, msg)
  if not x then
    error(msg)
  end
end

function check_nil(x, msg)
  if x ~= nil then
    error(msg..'; should be nil but got "'..x..'"')
  end
end

function check_eq(x, expected, msg)
  if not eq(x, expected) then
    error(msg..'; should be "'..expected..'" but got "'..x..'"')
  end
end

function eq(a, b)
  if type(a) ~= type(b) then return false end
  if type(a) == 'table' then
    if #a ~= #b then return false end
    for k, v in pairs(a) do
      if not eq(b[k], v) then
        return false
      end
    end
    for k, v in pairs(b) do
      if not eq(a[k], v) then
        return false
      end
    end
    return true
  end
  return a == b
end