testlib.lua

local Test = {
   last = nil,
   failed = nil,
   scope_info = nil,
}

function Test.fail(message)
   error(message or 'fail')
   return false
end

function Test.assert(pred, message)
   if not pred then
      return Test.fail(message)
   end
   return true
end

function Test.expect_fail(fn)
   assert(type(fn) == 'function')
   local ok, msg = pcall(fn)
   return Test.assert(not ok, msg)
end

function Test.info(info)
   Test.scope_info = Test.scope_info or {}
   table.insert(Test.scope_info, tostring(info))
end

function Test.reset()
   Test.scope_info = nil
end

function Test.run(tests)
   local ok, failed = 0, 0
   for k, v in pairs(tests) do
      Test.scope_info = nil
      if type(v) == 'function' then
         Test.failed = nil
         print("Running test " .. k)

         local output = {}
         local oldprint = _G.print
         _G.print = function(str)
            table.insert(output, str)
         end
         local status, err = pcall(v)
         _G.print = oldprint
         if status and not Test.failed then
            ok = ok + 1
            print("[OK    ]")
         else
            failed = failed + 1
            if type(err) == 'table' and err.desc then err = err.desc end
            print("[FAILED] " .. (Test.failed or (tostring(err) or "")))
            if Test.scope_info then
               if type(Test.scope_info) == 'string' then
                  print("[  info] " .. Test.scope_info)
               elseif type(Test.scope_info) == 'table' then
                  for _, line in ipairs(Test.scope_info) do
                     print("[  info] " .. line)
                  end
               end
            end
            for _, line in ipairs(output) do
               if type(line) == 'string' then
                  print("> " .. line)
               end
            end
         end
      end
   end

   print("Ran " .. (ok + failed) .. " tests (" .. ok .. " succeeded, " .. failed .. " failed)")
   if failed > 0 then
      os.exit(1)
   end
end

return Test