test(examples): add specs for gemfile format

lib/convenient_service/examples/standard/gemfile.rb

@@ -3,17 +3,18 @@
 require_relative "gemfile/services"
 
 ##
-# Usage example:
+# @internal
+#   Usage example:
 #
-# result = ConvenientService::Examples::Standard::Gemfile.format(path: "Gemfile")
-# result = ConvenientService::Examples::Standard::Gemfile.format(path: "spec/cli/gemfile/format/fixtures/Gemfile")
+#   result = ConvenientService::Examples::Standard::Gemfile.format(path: "Gemfile")
+#   result = ConvenientService::Examples::Standard::Gemfile.format(path: "spec/cli/gemfile/format/fixtures/Gemfile")
 #
 module ConvenientService
   module Examples
     module Standard
       module Gemfile
         class << self
-          def format
+          def format(path)
             Services::Format[path: path]
           end
         end

lib/convenient_service/examples/standard/gemfile/services/format.rb

@@ -14,6 +14,8 @@ module Services
           class Format
             include ConvenientService::Standard::Config
 
+            attr_reader :path
+
             step Services::ReadFileContent, in: :path, out: :content
             step Services::StripComments, in: :content, out: :content_without_comments
             step Services::ParseContent, in: {content: :content_without_comments}, out: :parsed_content

spec/lib/convenient_service/examples/standard/gemfile_spec.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+require "convenient_service"
+
+RSpec.describe ConvenientService::Examples::Standard::Gemfile do
+  include ConvenientService::RSpec::Matchers::DelegateTo
+
+  example_group "class methods" do
+    describe ".format" do
+      let(:file) { Tempfile.new }
+      let(:path) { file.path }
+
+      specify do
+        expect { described_class.format(path) }
+          .to delegate_to(described_class::Services::Format, :result)
+          .with_arguments(path: path)
+          .and_return_its_value
+      end
+    end
+  end
+end