Add test for DSL loader

Author: andyw8

spec/spec_helper.rb

@@ -17,6 +17,8 @@
 require "rails_spec_helper"
 require "mocha/minitest"
 
+require "debug/prelude"
+
 backtrace_filter = Minitest::ExtensibleBacktraceFilter.default_filter
 backtrace_filter.add_filter(%r{gems/sorbet-runtime})
 backtrace_filter.add_filter(%r{gems/railties})

spec/tapioca/loaders/dsl_spec.rb

@@ -0,0 +1,44 @@
+# typed: true
+# frozen_string_literal: true
+
+require "spec_helper"
+
+module Tapioca
+  module Loaders
+    class DslSpec < SpecWithProject
+      describe "#load_application" do
+        it "loads the application if `lsp_addon` is false" do
+          outputs = capture_io do
+            Loaders::Dsl.load_application(
+              tapioca_path: @project.absolute_path,
+              app_root: @project.absolute_path,
+              lsp_addon: false,
+            )
+          end
+
+          output = outputs.first # TODO: why are there two outputs?
+
+          assert_match(/Loading DSL extension classes.../, output)
+          assert_match(/Loading Rails application/, output)
+          assert_match(/Loading DSL compiler classes.../, output)
+        end
+
+        it "does not load the application if `lsp_addon` is true" do
+          outputs = capture_io do
+            Loaders::Dsl.load_application(
+              tapioca_path: @project.absolute_path,
+              app_root: @project.absolute_path,
+              lsp_addon: true,
+            )
+          end
+
+          output = outputs.first # TODO: why are there two outputs?
+
+          assert_match(/Loading DSL extension classes.../, output)
+          refute_match(/Loading Rails application/, output)
+          assert_match(/Loading DSL compiler classes.../, output)
+        end
+      end
+    end
+  end
+end