Update config to use uninitialized server

src/kemal.cr

@@ -11,6 +11,7 @@ module Kemal
     config.server = HTTP::Server.new(config.host_binding.not_nil!, config.port, config.handlers)
     config.server.ssl = config.ssl
 
+    unless config.env == "test"
       Signal::INT.trap {
         config.logger.write "Kemal is going to take a rest!\n"
         config.server.close
@@ -34,3 +35,4 @@ module Kemal
       config.server.listen
     end
   end
+end

src/kemal/config.cr

@@ -3,8 +3,6 @@ module Kemal
     INSTANCE = Config.new
     HANDLERS = [] of HTTP::Handler
 
-    @server : HTTP::Server
-
     property host_binding, ssl, port, env, public_folder, logging,
       always_rescue, error_handler, serve_static, server
 
@@ -18,6 +16,7 @@ module Kemal
       @logger = nil
       @always_rescue = true
       @error_handler = nil
+      @server = uninitialized HTTP::Server
     end
 
     def logger