test: test coverage should be at least 50%

Gemfile

@@ -68,10 +68,11 @@ group :test do
   # Use system testing [https://guides.rubyonrails.org/testing.html#system-testing]
   gem "capybara"
   gem "selenium-webdriver"
+  gem 'simplecov'
 end
 
 group :production do
   gem 'pg'
 end
 
-gem 'aws-sdk-s3', '~> 1'
+gem 'aws-sdk-s3', '~> 1'

Gemfile.lock

@@ -121,6 +121,7 @@ GEM
     debug (1.9.2)
       irb (~> 1.10)
       reline (>= 0.3.8)
+    docile (1.4.1)
     drb (2.2.1)
     erubi (1.13.0)
     globalid (1.2.1)
@@ -256,6 +257,12 @@ GEM
       rexml (~> 3.2, >= 3.2.5)
       rubyzip (>= 1.2.2, < 3.0)
       websocket (~> 1.0)
+    simplecov (0.22.0)
+      docile (~> 1.1)
+      simplecov-html (~> 0.11)
+      simplecov_json_formatter (~> 0.1)
+    simplecov-html (0.13.1)
+    simplecov_json_formatter (0.1.4)
     sprockets (4.2.1)
       concurrent-ruby (~> 1.0)
       rack (>= 2.2.4, < 4)
@@ -318,6 +325,7 @@ DEPENDENCIES
   rails (~> 7.1.3, >= 7.1.3.4)
   rubocop
   selenium-webdriver
+  simplecov
   sprockets-rails
   sqlite3 (~> 1.4)
   stimulus-rails

app/models/message.rb

@@ -10,9 +10,8 @@ class Message < ApplicationRecord
     # https://blade.ruby-lang.org/ruby-talk/410000 is not.
     self.skip_time_zone_conversion_for_attributes = [:published_at]
 
-    def self.from_s3(list_name, list_seq)
-        client = Aws::S3::Client.new(region: BLADE_BUCKET_REGION)
-        obj = client.get_object(bucket: BLADE_BUCKET_NAME, key: "#{list_name}/#{list_seq}")
+    def self.from_s3(list_name, list_seq, s3_client = Aws::S3::Client.new(region: BLADE_BUCKET_REGION))
+        obj = s3_client.get_object(bucket: BLADE_BUCKET_NAME, key: "#{list_name}/#{list_seq}")
 
         m = self.from_string(obj.body.read)
         m.list_id = List.find_by_name(list_name).id

test/models/list_test.rb

@@ -4,4 +4,8 @@ class ListTest < ActiveSupport::TestCase
   test 'name' do
     assert_equal 'ruby-list', List::find_by_name('ruby-list').name
   end
+
+  test 'find_by_id' do
+    assert_equal 'ruby-list', List.find_by_id(1).name
+  end
 end

test/models/message_test.rb

@@ -14,4 +14,16 @@ class MessageTest < ActiveSupport::TestCase
 
     assert_equal DateTime.parse('2005-12-15T19:32:40+09:00'), m.published_at
   end
+
+  test 'from_s3' do
+    s3_client = Aws::S3::Client.new(stub_responses: true)
+    s3_client.stub_responses(:get_object, body: <<END_OF_BODY)
+Subject: [ruby-list:1] Hello
+From: alice@...
+Date: 2005-12-15T19:32:40+09:00
+
+Hello, world!
+END_OF_BODY
+    Message.from_s3('ruby-list', 1234, s3_client)
+  end
 end

test/test_helper.rb

@@ -1,7 +1,12 @@
+require 'simplecov'
+SimpleCov.start 'rails'
+SimpleCov.minimum_coverage 50
+
 ENV["RAILS_ENV"] ||= "test"
 require_relative "../config/environment"
 require "rails/test_help"
 
+
 module ActiveSupport
   class TestCase
     # Run tests in parallel with specified workers