Add test for lsp_addon flag in CLI

spec/tapioca/cli_spec.rb

@@ -0,0 +1,28 @@
+# typed: true
+# frozen_string_literal: true
+
+require "spec_helper"
+
+module Tapioca
+  class CliSpec < SpecWithProject
+    before do
+      @command_stub = stub(run: nil)
+    end
+
+    it "passes through the `lsp_addon` flag to the DslGenerate command" do
+      Commands::DslGenerate.expects(:new).with do |options|
+        options[:lsp_addon] == true
+      end.returns(@command_stub)
+
+      capture_io { Cli.start(["dsl", "--lsp_addon"]) }.join
+    end
+
+    it "does not through the `lsp_addon` flag to the DslGenerate command when not present" do
+      Commands::DslGenerate.expects(:new).with do |options|
+        options[:lsp_addon].nil?
+      end.returns(@command_stub)
+
+      capture_io { Cli.start(["dsl", "--another-flag"]) }.join
+    end
+  end
+end