Add testing for DSL RBI generation

.gitignore

@@ -8,3 +8,5 @@
 /spec/reports/
 /tmp/
 /vendor/
+/test/dummy/log/
+/test/dummy/tmp/

.rubocop.yml

@@ -47,6 +47,7 @@ Sorbet/TrueSigil:
     - "**/*.rake"
   Exclude:
     - "lib/ruby_lsp/tapioca/server_addon.rb"
+    - "test/dummy/**/*.rb"
 
 Style/CaseEquality:
   Enabled: false

spec/addon_spec_helper.rb

@@ -0,0 +1,43 @@
+# typed: true
+# frozen_string_literal: true
+
+# Configure Rails Environment
+ENV["RAILS_ENV"] = "test"
+
+require "minitest/spec"
+require "ruby_lsp/internal"
+require "ruby_lsp/test_helper"
+
+module ActiveSupport
+  class TestCase
+    include RubyLsp::TestHelper
+
+    def pop_result(server)
+      result = server.pop_response
+      result = server.pop_response until result.is_a?(RubyLsp::Result) || result.is_a?(RubyLsp::Error)
+
+      refute_instance_of(
+        RubyLsp::Error,
+        result,
+        -> { "Failed to execute request #{T.cast(result, RubyLsp::Error).message}" },
+      )
+      T.cast(result, RubyLsp::Result)
+    end
+
+    def pop_log_notification(message_queue, type)
+      log = message_queue.pop
+      return log if log.params.type == type
+
+      log = message_queue.pop until log.params.type == type
+      log
+    end
+
+    def pop_message(outgoing_queue, &block)
+      message = outgoing_queue.pop
+      return message if block.call(message)
+
+      message = outgoing_queue.pop until block.call(message)
+      message
+    end
+  end
+end

spec/tapioca/addon_spec.rb

@@ -0,0 +1,55 @@
+# typed: true
+# frozen_string_literal: true
+
+require "addon_spec_helper"
+require "ruby_lsp/ruby_lsp_rails/runner_client"
+require "spoom/context"
+require "minitest/hooks"
+
+module RubyLsp
+  module Tapioca
+    class RunnerClientTest < Minitest::HooksSpec
+      # The approach here is based on tests within the Ruby LSP Rails gem
+
+      before do
+        FileUtils.cp("test/dummy/bin/rails", "bin/rails")
+        @outgoing_queue = Thread::Queue.new
+        @client = T.let(RubyLsp::Rails::RunnerClient.new(@outgoing_queue), RubyLsp::Rails::RunnerClient)
+      end
+
+      after do
+        @client.shutdown
+
+        # On Windows, the server process sometimes takes a lot longer to shutdown and may end up getting force killed,
+        # which makes this assertion flaky
+        assert_predicate(@client, :stopped?) unless Gem.win_platform?
+        @outgoing_queue.close
+        FileUtils.rm("bin/rails")
+      end
+
+      EXPECTED_RBI_PATH = "sorbet/rbi/dsl/notify_user_job.rbi"
+      it "generates DSL RBIs for a gem" do
+        raise "RBI already exists" if File.exist?(EXPECTED_RBI_PATH)
+
+        addon_path = File.expand_path("lib/ruby_lsp/tapioca/server_addon.rb")
+        @client.register_server_addon(File.expand_path(addon_path))
+        @client.delegate_notification(
+          server_addon_name: "Tapioca",
+          request_name: "dsl",
+          constants: ["NotifyUserJob"],
+        )
+
+        begin
+          Timeout.timeout(10) do
+            until File.exist?(EXPECTED_RBI_PATH)
+            end
+          end
+        rescue Timeout::Error
+          flunk("RBI file was not generated")
+        end
+      ensure
+        FileUtils.rm_f(EXPECTED_RBI_PATH)
+      end
+    end
+  end
+end

test/dummy/app/models/notify_user_job.rb

@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class NotifyUserJob < ActiveJob::Base
+  def perform(user)
+  end
+end

test/dummy/bin/rails

@@ -0,0 +1,14 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+# This command will automatically be run when you run "rails" with Rails gems
+# installed from the root of your application.
+
+ENGINE_ROOT = File.expand_path("..", __dir__)
+APP_PATH = File.expand_path("../test/dummy/config/application", __dir__)
+
+# Set up gems listed in the Gemfile.
+ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../Gemfile", __dir__)
+require "bundler/setup" if File.exist?(ENV["BUNDLE_GEMFILE"])
+
+require "rails/engine/commands"

test/dummy/config.ru

@@ -0,0 +1,7 @@
+# typed: strict
+# frozen_string_literal: true
+
+require_relative "config/environment"
+
+run Rails.application
+Rails.application.load_server

test/dummy/config/application.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../../../Gemfile", __dir__)
+
+require "bundler/setup" if File.exist?(ENV["BUNDLE_GEMFILE"])
+$LOAD_PATH.unshift(File.expand_path("../../../lib", __dir__))
+
+require "rails" # minimal, instead of "rails/all"
+require "active_job/railtie"
+
+Bundler.require(*Rails.groups)
+
+module Dummy
+  class Application < Rails::Application
+  end
+end

test/dummy/config/environment.rb

@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+require_relative "application"
+
+Rails.application.initialize!