谢谢大腿荐书，先大致过完手上这本就去看

@piecehealth @Rei @tinyfeng 感谢各位大腿的帮助，刚刚已经成功解决了问题

问题所在

我看的是《Ruby on Rails 教程》样章试读
这个链接是之前官网的样章试读链接，直接从网页打开
这个版本中的样章中的 rails 版本是 5.1.2
现在从官网链接进去点击样章试读是下载一个 pdf，其中 rails 的版本是 5.1.6（中间也就差了一两天）
在各章给出的 Gemfile 文件中也只有 rails 的版本这一个不同gem 'rails', '5.1.6'
在将 Gemfile 文件根据最新的电子书修改后，已经没有了本贴所描述的问题

再次感谢三位大腿的帮助
我已购买此电子书以便接收它的最新更新
（吐槽：之前买的实体书上面 rails 的版本是 5.0.0）

如果没有更多讨论，我将与下周之前关闭这个贴子，谢谢

抱住大佬的大腿哭

我这个测试就是为了得到失败，但是得到的失败信息不对，大佬可以看下 16 楼我重现的结果，似乎是 gem 包的问题

@piecehealth @Rei 我刚刚重现这个问题去了，发现问题好像是某个 gem 包的问题（但是我才刚入门不懂 gem 包怎么选啊都是按教程来的 ）

$ rails _5.1.2_ new test_app
$ cd test_app
$ rails generate controller Pages home help
$ rails test

一直到这里都没问题（虽然会提示要跑rails db:migrate但是不影响 test 结果）
然后我在 test/controllers/pages_controller_test.rb 中添加两个失败测试（后两个）

require 'test_helper'

class PagesControllerTest < ActionDispatch::IntegrationTest
  test "should get home" do
    get pages_home_url
    assert_response :success
  end

  test "should get help" do
    get pages_help_url
    assert_response :success
  end

  test "should get about" do
    get pages_about_url
    assert_response :success
  end

  test "should get contact" do
    get pages_contact_url
    assert_response :success
  end
end

再运行rails test可以得到预期的结果

sws@Ubuntu:~/ruby_on_rails/environment/bbb_app$ rails test
Running via Spring preloader in process 6083
/home/sws/ruby_on_rails/environment/bbb_app/db/schema.rb doesn't exist yet. Run `rails db:migrate` to create it, then try again. If you do not intend to use a database, you should instead alter /home/sws/ruby_on_rails/environment/bbb_app/config/application.rb to limit the frameworks that will be loaded.
Run options: --seed 34068

# Running:

.E

Error:
PagesControllerTest#test_should_get_about:
NameError: undefined local variable or method `pages_about_url' for #<PagesControllerTest:0x0000000005b8ecf0>
    test/controllers/pages_controller_test.rb:15:in `block in <class:PagesControllerTest>'


bin/rails test test/controllers/pages_controller_test.rb:14

E

Error:
PagesControllerTest#test_should_get_contact:
NameError: undefined local variable or method `pages_contact_url' for #<PagesControllerTest:0x000000000559a560>
    test/controllers/pages_controller_test.rb:20:in `block in <class:PagesControllerTest>'


bin/rails test test/controllers/pages_controller_test.rb:19

.

Finished in 0.358412s, 11.1603 runs/s, 5.5802 assertions/s.
4 runs, 2 assertions, 0 failures, 2 errors, 0 skips

但是当我按教程要求更新 Gemfile 之后
原 gemfile（我去掉了注释）

source 'https://rubygems.org'

git_source(:github) do |repo_name|
  repo_name = "#{repo_name}/#{repo_name}" unless repo_name.include?("/")
  "https://github.com/#{repo_name}.git"
end

gem 'rails', '~> 5.1.2'
gem 'sqlite3'
gem 'puma', '~> 3.7'
gem 'sass-rails', '~> 5.0'
gem 'uglifier', '>= 1.3.0'
gem 'coffee-rails', '~> 4.2'
gem 'turbolinks', '~> 5'
gem 'jbuilder', '~> 2.5'

group :development, :test do
  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
  gem 'capybara', '~> 2.13'
  gem 'selenium-webdriver'
end

group :development do
  gem 'web-console', '>= 3.3.0'
  gem 'listen', '>= 3.0.5', '< 3.2'
  gem 'spring'
  gem 'spring-watcher-listen', '~> 2.0.0'
end

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

修改后的 gemfile

source 'https://rubygems.org'

gem 'rails', '5.1.2'
gem 'puma', '3.9.1'
gem 'sass-rails', '5.0.6'
gem 'uglifier', '3.2.0'
gem 'coffee-rails', '4.2.2'
gem 'jquery-rails', '4.3.1'
gem 'turbolinks', '5.0.1'
gem 'jbuilder', '2.7.0'

group :development, :test do
  gem 'sqlite3', '1.3.13'
  gem 'byebug', '9.0.6', platform: :mri
end

group :development do
  gem 'web-console', '3.5.1'
  gem 'listen', '3.0.8'
  gem 'spring', '2.0.2'
  gem 'spring-watcher-listen', '2.0.1'
end

group :test do
  gem 'rails-controller-testing', '1.0.2'
  gem 'minitest-reporters', '1.1.14'
  gem 'guard', '2.13.0'
  gem 'guard-minitest', '2.4.4'
end

group :production do
  gem 'pg', '0.20.0'
end

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

更新 gem 包

$ bundle install --without production
$ bundle update

这时候再跑rails test就不能正常运行了

sws@Ubuntu:~/ruby_on_rails/environment/aaa_app$ rails test
Running via Spring preloader in process 25721
/home/sws/ruby_on_rails/environment/aaa_app/db/schema.rb doesn't exist yet. Run `rails db:migrate` to create it, then try again. If you do not intend to use a database, you should instead alter /home/sws/ruby_on_rails/environment/aaa_app/config/application.rb to limit the frameworks that will be loaded.
Run options: --seed 13155

# Running:

E

Error:
PagesControllerTest#test_should_get_about:
NameError: undefined local variable or method `pages_about_url' for #<PagesControllerTest:0x0000000003caa708>
    test/controllers/pages_controller_test.rb:15:in `block in <class:PagesControllerTest>'


/home/sws/.rvm/gems/ruby-2.4.4/gems/railties-5.1.2/lib/rails/test_unit/reporter.rb:70:in `method': undefined method `test_should_get_about' for class `Minitest::Result' (NameError)
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/railties-5.1.2/lib/rails/test_unit/reporter.rb:70:in `format_rerun_snippet'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/railties-5.1.2/lib/rails/test_unit/reporter.rb:23:in `record'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/minitest-reporters-1.1.14/lib/minitest/minitest_reporter_plugin.rb:21:in `block in record'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/minitest-reporters-1.1.14/lib/minitest/minitest_reporter_plugin.rb:20:in `each'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/minitest-reporters-1.1.14/lib/minitest/minitest_reporter_plugin.rb:20:in `record'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/minitest-5.11.3/lib/minitest.rb:803:in `block in record'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/minitest-5.11.3/lib/minitest.rb:802:in `each'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/minitest-5.11.3/lib/minitest.rb:802:in `record'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/minitest-5.11.3/lib/minitest.rb:334:in `run_one_method'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/minitest-5.11.3/lib/minitest.rb:321:in `block (2 levels) in run'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/minitest-5.11.3/lib/minitest.rb:320:in `each'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/minitest-5.11.3/lib/minitest.rb:320:in `block in run'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/minitest-5.11.3/lib/minitest.rb:360:in `on_signal'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/minitest-5.11.3/lib/minitest.rb:347:in `with_info_handler'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/minitest-5.11.3/lib/minitest.rb:319:in `run'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/railties-5.1.2/lib/rails/test_unit/line_filtering.rb:11:in `run'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/minitest-5.11.3/lib/minitest.rb:159:in `block in __run'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/minitest-5.11.3/lib/minitest.rb:159:in `map'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/minitest-5.11.3/lib/minitest.rb:159:in `__run'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/minitest-5.11.3/lib/minitest.rb:136:in `run'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/railties-5.1.2/lib/rails/test_unit/minitest_plugin.rb:77:in `run'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/minitest-5.11.3/lib/minitest.rb:63:in `block in autorun'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/spring-2.0.2/lib/spring/application.rb:171:in `fork'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/spring-2.0.2/lib/spring/application.rb:171:in `serve'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/spring-2.0.2/lib/spring/application.rb:141:in `block in run'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/spring-2.0.2/lib/spring/application.rb:135:in `loop'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/spring-2.0.2/lib/spring/application.rb:135:in `run'
    from /home/sws/.rvm/gems/ruby-2.4.4/gems/spring-2.0.2/lib/spring/application/boot.rb:19:in `<top (required)>'
    from /home/sws/.rvm/rubies/ruby-2.4.4/lib/ruby/site_ruby/2.4.0/rubygems/core_ext/kernel_require.rb:59:in `require'
    from /home/sws/.rvm/rubies/ruby-2.4.4/lib/ruby/site_ruby/2.4.0/rubygems/core_ext/kernel_require.rb:59:in `require'
    from -e:1:in `<main>'

那就是了，现在就是整个项目只有一个 test.rb，里面有 4 个 test，两个成功两个失败
但是 rails test 在跑到第一个失败的时候就告诉我“嘿，你这里没写”，然后第四个 test 不跑了
不告诉我“你跑了 4 个测试，错了两个” 咋办啊

test case 是指的一个 xxx_test.rb 的文件吗，
还是指的一个 test xxx end？

我这里只有一个 test.rb 的文件，其它目录只有一个 .keep 文件
这个文件里面只有脚手架自动添加的两个 test xxx end，和一个预期就是失败的 test about xxx end
（后面还添了第二个失败的 test）

没有省略的说明。
主要问题在教程中说如果写 3 个测试，如果有 1 个错误的话会告诉我

3 tests, 2 assertions, 0 failures, 1 errors, 0 skips

但是没有这句话，当我写 4 个测试，已知有 2 个错误，那么 rails test 的结果应该有一句话

4 tests, 2 assertions, 0 failures, 2 errors, 0 skips

但是也没有这句话，并且报错和写 3 错 1 的输出是一样的，也就是在问题中有贴报错信息的部分
那么如果我写了 100 个测试，其中有 10 个失败了，那么我也只能得到其中的一个失败
rails test 应该有总结性的语句告诉我我跑了 100 个失败了 10 个，但是并没有
它现在只告诉我“你这个页面没写”，不会告诉我另外 9 个错误的事情

是的我知道失败是符合预期的，但是失败输出的结果不符合预期。
我只使用脚手架添加了 home 和 help，但是在 test 中加入了 about
按照教程中给出的结果，rails test 应该有一句话告诉我

3 tests, 2 assertions, 0 failures, 1 errors, 0 skips

但实际上没有这句话，于是我做了测试

在只使用脚手架添加 home 和 help 的情况下，我在 test 中额外加入了 about 和 contact 两个的失败测试
预期的 rails test 的结果应该是

4 tests, 2 assertions, 0 failures, 2 errors, 0 skips

但实际上在检测到 about 路由未定义的时候就不会再检测到 contact 的错误了
也就是没有这句总结性的语句（来表示我跑了多少个测试）的输出
而 rails test 输出的结果和只添加一个 about 的检测一样（都在上面给出了）
只会说 about 未定义

我下面那个回复可能组织语言更加清楚

抱歉没看明白，测试的父类确实是这个，但是代码里面本身就是static_pages_about_url啊

require 'test_helper'
class StaticPagesControllerTest < ActionDispatch::IntegrationTest
...
  test 'should get about' do
    get static_pages_about_url
    assert_response :success
  end
end