Refactor global namespace DSL into OOP Kemal::Base

spec/spec_helper.cr

@@ -1,5 +1,7 @@
 require "spec"
-require "../src/*"
+require "../src/**"
+require "../src/kemal/base"
+require "../src/kemal/dsl"
 
 include Kemal
 
@@ -33,6 +35,7 @@ def create_request_and_return_io_and_context(handler, request)
   io = IO::Memory.new
   response = HTTP::Server::Response.new(io)
   context = HTTP::Server::Context.new(request, response)
+  context.app = Kemal.application
   handler.call(context)
   response.close
   io.rewind
@@ -43,6 +46,7 @@ def create_ws_request_and_return_io_and_context(handler, request)
   io = IO::Memory.new
   response = HTTP::Server::Response.new(io)
   context = HTTP::Server::Context.new(request, response)
+  context.app = Kemal.application
   begin
     handler.call context
   rescue IO::Error
@@ -64,10 +68,10 @@ def call_request_on_app(request)
 end
 
 def build_main_handler
-  Kemal.config.setup
-  main_handler = Kemal.config.handlers.first
+  Kemal.application.setup
+  main_handler = Kemal.application.handlers.first
   current_handler = main_handler
-  Kemal.config.handlers.each do |handler|
+  Kemal.application.handlers.each_with_index do |handler, index|
     current_handler.next = handler
     current_handler = handler
   end
@@ -81,8 +85,5 @@ Spec.before_each do
 end
 
 Spec.after_each do
-  Kemal.config.clear
-  Kemal::RouteHandler::INSTANCE.routes = Radix::Tree(Route).new
-  Kemal::RouteHandler::INSTANCE.cached_routes = Hash(String, Radix::Result(Route)).new
-  Kemal::WebSocketHandler::INSTANCE.routes = Radix::Tree(WebSocket).new
+  Kemal.application.clear
 end