test: add test harness with http and router tests

test/run_all.rb

@@ -0,0 +1,6 @@
+$LOAD_PATH.unshift(File.expand_path('../lib', __dir__))
+$LOAD_PATH.unshift(__dir__)
+
+require 'minitest/autorun'
+
+Dir[File.join(__dir__, 'test_*.rb')].sort.each { |file| require file }