Errno::ENOENT：功能测试后没有这样的文件或目录@rb_file_s_mtime
Errno::ENOENT: No such file or directory @ rb_file_s_mtime after feature tests
当 运行ning 功能 Rspecs 时，我收到以下错误（此消息底部的完整跟踪）
Puma 输出
Rack app error handling request { GET /rails/active_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--db9451afdc95b292aa6a77c40e00ab0ceb687766/image.png }
#<Errno::ENOENT: No such file or directory @ rb_file_s_mtime - /path/to/rails/app/tmp/storage/va/ri/variants/Gpu41CMPPeKLiMbfpzYYyCp5/110e017d16925dc7c50728c9c154a420079aa6e5fcc435db3e6e97b1380ecec8>
(followed by the full trace at the end of this message)
Rspec输出
Failure/Error: last_modified = ::File.mtime(path).httpdate
Errno::ENOENT:
No such file or directory @ rb_file_s_mtime - /path/to/rails/app/tmp/storage/va/ri/variants/Gpu41CMPPeKLiMbfpzYYyCp5/110e017d16925dc7c50728c9c154a420079aa6e5fcc435db3e6e97b1380ecec8
(followed by the full trace at the end of this message)
上下文
product.image 是一个 ActiveStorage 附件。在测试期间，"products/_form" 部分被渲染并显示附件文件（即 png 图像），代码如下：= image_tag url_for(product.image.variant(resize: "120x120"))。如果我注释掉这一行，错误就不会再发生了。
测试本身每次都成功，错误似乎是在测试后触发的。我验证了我所有的 after 块，它似乎发生在我所有的块之后。
跟踪表明 ActiveStorage::DiskController.serve_file 触发了错误。是不是 ActiveStorage 应用程序没有正常关闭？
我正在使用 active_storage.service = :test 配置，但 :file 给出了同样的错误。
图像损坏
虽然测试失败，但我可以在 "remote controlled" 浏览器中看到图像没有显示，而是有一个损坏的图像图标。
运行 测试
有一组 4 个特色测试正在通过 "products/_form" 部分的渲染。当我 运行 以随机顺序进行 4 次测试时，错误随机发生。有时我可以看到错误 2 次，有时 3 次。
当我 运行 单独测试时，错误永远不会出现。
我如何附上图片
这是我在进行测试之前用来将文件附加到模型的助手：
path = Rails.root.join 'spec', 'support', 'fixtures', 'img1.png'
raise 'Image does not exist' unless File.exist? path
product.image.attach io: File.open(path), filename: 'image.png'
我也试过用这个助手:
path = Rails.root.join 'spec', 'support', 'fixtures', 'img1.png'
raise 'Image does not exist' unless File.exist? path
blob = ActiveStorage::Blob.create_after_upload! io: path.open, \
filename: 'img1.png', content_type: 'image/png'
product.images.attach blob
还有这个帮手：
path = Rails.root.join 'spec', 'support', 'fixtures', 'img1.png'
raise 'Image does not exist' unless File.exist? path
byte_size = path.size
checksum = Digest::MD5.file(path).base64digest
blob = ActiveStorage::Blob.create_before_direct_upload!(filename: 'img1.png', \
byte_size: byte_size, checksum: checksum, content_type: 'image/png').tap do |blob|
ActiveStorage::Blob.service.upload(blob.key, path.open)
end
product.images.attach blob
系统配置
Rails 版本: 5.2.2
Ruby 版本：ruby 2.5.3p105（2018-10-18 修订版 65156）[x86_64-linux]
Rbenv 版本：rbenv 1.1.1-39-g59785f6
Rspec 相关版本: rspec 3.8.0 - 水豚 3.12.0 - selenium-webdriver 3.141.0
完整跟踪
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/file.rb:63:in `mtime'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/file.rb:63:in `serving'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activestorage-5.2.2/app/controllers/active_storage/disk_controller.rb:42:in `serve_file'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activestorage-5.2.2/app/controllers/active_storage/disk_controller.rb:12:in `show'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_controller/metal/basic_implicit_render.rb:6:in `send_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/abstract_controller/base.rb:194:in `process_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_controller/metal/rendering.rb:30:in `process_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/abstract_controller/callbacks.rb:42:in `block in process_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activesupport-5.2.2/lib/active_support/callbacks.rb:132:in `run_callbacks'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/abstract_controller/callbacks.rb:41:in `process_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_controller/metal/rescue.rb:22:in `process_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_controller/metal/instrumentation.rb:34:in `block in process_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activesupport-5.2.2/lib/active_support/notifications.rb:168:in `block in instrument'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activesupport-5.2.2/lib/active_support/notifications/instrumenter.rb:23:in `instrument'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activesupport-5.2.2/lib/active_support/notifications.rb:168:in `instrument'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_controller/metal/instrumentation.rb:32:in `process_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_controller/metal/params_wrapper.rb:256:in `process_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activerecord-5.2.2/lib/active_record/railties/controller_runtime.rb:24:in `process_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/abstract_controller/base.rb:134:in `process'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionview-5.2.2/lib/action_view/rendering.rb:32:in `process'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_controller/metal.rb:191:in `dispatch'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_controller/metal.rb:252:in `dispatch'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/routing/route_set.rb:52:in `dispatch'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/routing/route_set.rb:34:in `serve'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/journey/router.rb:52:in `block in serve'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/journey/router.rb:35:in `each'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/journey/router.rb:35:in `serve'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/routing/route_set.rb:840:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/tempfile_reaper.rb:15:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/etag.rb:25:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/conditional_get.rb:25:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/head.rb:12:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/http/content_security_policy.rb:18:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/session/abstract/id.rb:232:in `context'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/session/abstract/id.rb:226:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/middleware/cookies.rb:670:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activesupport-5.2.2/lib/active_support/callbacks.rb:98:in `run_callbacks'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/middleware/callbacks.rb:26:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/middleware/debug_exceptions.rb:61:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/middleware/show_exceptions.rb:33:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/railties-5.2.2/lib/rails/rack/logger.rb:38:in `call_app'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/railties-5.2.2/lib/rails/rack/logger.rb:26:in `block in call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activesupport-5.2.2/lib/active_support/tagged_logging.rb:71:in `block in tagged'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activesupport-5.2.2/lib/active_support/tagged_logging.rb:28:in `tagged'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activesupport-5.2.2/lib/active_support/tagged_logging.rb:71:in `tagged'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/railties-5.2.2/lib/rails/rack/logger.rb:26:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/middleware/remote_ip.rb:81:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/middleware/request_id.rb:27:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/method_override.rb:22:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/runtime.rb:22:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activesupport-5.2.2/lib/active_support/cache/strategy/local_cache_middleware.rb:29:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/middleware/executor.rb:14:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/middleware/static.rb:127:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/sendfile.rb:111:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/railties-5.2.2/lib/rails/engine.rb:524:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/urlmap.rb:68:in `block in call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/urlmap.rb:53:in `each'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/urlmap.rb:53:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/capybara-3.12.0/lib/capybara/server/middleware.rb:48:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/puma-3.12.0/lib/puma/configuration.rb:225:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/puma-3.12.0/lib/puma/server.rb:658:in `handle_request'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/puma-3.12.0/lib/puma/server.rb:472:in `process_client'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/puma-3.12.0/lib/puma/server.rb:332:in `block in run'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/puma-3.12.0/lib/puma/thread_pool.rb:133:in `block in spawn_thread'
#
# Showing full backtrace because every line was filtered out.
# See docs for RSpec::Configuration#backtrace_exclusion_patterns and
# RSpec::Configuration#backtrace_inclusion_patterns for more information.
# ------------------
# --- Caused by: ---
# Capybara::CapybaraError:
# Your application server raised an error - It has been raised in your test code because Capybara.raise_server_errors == true
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/capybara-3.12.0/lib/capybara/session.rb:147:in `raise_server_error!'
更新
（抱歉失言，我有急事要处理）
这是一个有趣的信息。我在this line之后插入了这个代码：puts "SERVING #{path} - Exist ? #{File.exist? path}"
这是输出（观察文件名和每行末尾的布尔值）：
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/Me/GK/MeGKkqgbb7Sg4RbPoCYWR6pZ - Exist ? true
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/sG/3v/sG3vd2viGWmaf69pNXSChZPa - Exist ? true
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/fy/2C/fy2C8PpaR96YgCzwt5WVBLrQ - Exist ? true
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/sG/3v/sG3vd2viGWmaf69pNXSChZPa - Exist ? true
. (green dot)
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/Me/GK/MeGKkqgbb7Sg4RbPoCYWR6pZ - Exist ? false
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/sG/3v/sG3vd2viGWmaf69pNXSChZPa - Exist ? false
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/Me/GK/MeGKkqgbb7Sg4RbPoCYWR6pZ - Exist ? false
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/fy/2C/fy2C8PpaR96YgCzwt5WVBLrQ - Exist ? false
F (red F)
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/Me/GK/MeGKkqgbb7Sg4RbPoCYWR6pZ - Exist ? false
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/sG/3v/sG3vd2viGWmaf69pNXSChZPa - Exist ? false
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/Me/GK/MeGKkqgbb7Sg4RbPoCYWR6pZ - Exist ? false
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/fy/2C/fy2C8PpaR96YgCzwt5WVBLrQ - Exist ? false
F (red F)
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/Tx/DL/TxDLPEk3ykf8ETkURY5YZPgY - Exist ? true
正如我们所见，文件路径是相同的，即使在测试之间也是如此。每次测试之间都会清理数据库。所以有 "somewhere" 保存文件校验和的地方，以便 activestorage 重用相同的 blob 记录。结果它重用了相同的文件路径，这就是我遇到 FileNotFound 错误的原因。
有什么想法吗？请注意，除了 DatabaseCleaner 之外，我还有一个像这样定义的后块：
config.after(:each) do
ActiveStorage::Current.reset
ActiveStorage::Attachment.all.each(&:delete)
ActiveStorage::Blob.all.each(&:delete)
end
我怀疑有错误
已填写 PR 并申请重现 https://github.com/rails/rails/issues/34989
等待他们的回应
我不确定你的意思是测试后发生异常？
测试通常应该是原子的和独立的，因此您创建的所有资源都应该在测试完成后立即删除。
此外，测试 运行 以随机顺序排列，因此相互依赖的测试有时会失败 - 有时不会失败，具体取决于 运行 顺序。
你能分享失败的输出或测试吗？
您设置测试图像的方式可能有问题。您可能希望将其更新为 Rails 团队在他们自己的测试中处理它的方式：
module ActiveStorageHelpers
# ported from https://github.com/rails/rails/blob/5-2-stable/activestorage/test/test_helper.rb#L57
def create_file_blob(filename: "image.jpg", content_type: "image/jpeg", metadata: nil)
ActiveStorage::Blob.create_after_upload! io: file_fixture(filename).open, filename: filename, content_type: content_type, metadata: metadata
end
end
RSpec.configure do |config|
config.include ActiveStorageHelpers
end
然后在 spec/fixtures/file/images.jpg 中放置一个小图像文件（file_fixture 方法将在此处查找它）。
设置好后，您可以在功能测试中使用类似以下内容在模型上设置图像：
instance_of_model.images.attach(create_file_blob)
测试通过的事实仅意味着测试不依赖于找到的图像。损坏的图像 link 通常不会导致测试失败，事实上，通常情况下，测试编写者甚至懒得提供模拟图像，因为它（被认为）工作量太大而且与测试无关正在测试的东西。
各位看官，这就是我们ask for an example. Now that the OP has posted an example的原因，可以看出他的问题是浏览器缓存问题，通过更换
来解决
product.images.attach io: File.open(path), filename: 'image.png'
和
product.images.attach io: File.open(path), filename: "image-#{Time.now.strftime("%s%L")}.png"
在执行附件的助手中。如果没有这个例子，我不会解决这个问题。
说明
ActiveStorage 处理文件的保存和服务。 OP 用它来保存和提供图像，这绝对是它的目的。为了允许不同的服务以不同的方式提供文件，ActiveStorage 将发布的 URL 与实际的图像服务 URL.
分开
已发布的 URL 几乎是永久的link：它是附件数据库密钥的编码版本。 ActiveStorage 通过查找文件的存储位置并将 302 临时重定向发送到可用于访问文件的 URL 来处理对 URL 的请求，称为 "service URL"。当使用 AWS S3 存储文件时，服务 URL 可以是已签名的 URL，它会很快过期，但仍会将浏览器直接连接到 S3，而不必通过作为中介的 Web 服务器。
默认情况下，服务 URL 有效 5 分钟，ActiveRecord 显式设置
Cache-Control: max-age=300, private
在 302 重定向上。浏览器缓存此重定向响应，在接下来的 5 分钟内，浏览器甚至不会尝试使用或验证已发布的 URL，它会立即将 public URL 替换为缓存的服务 URL.
不幸的是，虽然 public URL 可以预见地重新创建，但服务 URL 是随机生成的，因此当浏览器进行自动重定向时，之前有效的服务 URL 不再有效。解决方案（或解决方法，取决于您的观点）是通过在文件名中包含时间戳来区分 public URL，这样测试就不会重复使用 public URLs.
旁注
顺便说一句，您不应该将 url_for 与 image_tag 一起使用。将您的 ERB 更改为
= image_tag url_for(product.image.variant(resize: "120x120"))
至
= image_tag(product.image.variant(resize: "120x120"))
Rails 足够聪明，可以处理任何一种情况，但后一种方式是推荐的方式。
当 运行ning 功能 Rspecs 时，我收到以下错误（此消息底部的完整跟踪）
Puma 输出
Rack app error handling request { GET /rails/active_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--db9451afdc95b292aa6a77c40e00ab0ceb687766/image.png }
#<Errno::ENOENT: No such file or directory @ rb_file_s_mtime - /path/to/rails/app/tmp/storage/va/ri/variants/Gpu41CMPPeKLiMbfpzYYyCp5/110e017d16925dc7c50728c9c154a420079aa6e5fcc435db3e6e97b1380ecec8>
(followed by the full trace at the end of this message)
Rspec输出
Failure/Error: last_modified = ::File.mtime(path).httpdate
Errno::ENOENT:
No such file or directory @ rb_file_s_mtime - /path/to/rails/app/tmp/storage/va/ri/variants/Gpu41CMPPeKLiMbfpzYYyCp5/110e017d16925dc7c50728c9c154a420079aa6e5fcc435db3e6e97b1380ecec8
(followed by the full trace at the end of this message)
上下文
product.image 是一个 ActiveStorage 附件。在测试期间，"products/_form" 部分被渲染并显示附件文件（即 png 图像），代码如下：= image_tag url_for(product.image.variant(resize: "120x120"))。如果我注释掉这一行，错误就不会再发生了。
测试本身每次都成功，错误似乎是在测试后触发的。我验证了我所有的 after 块，它似乎发生在我所有的块之后。
跟踪表明 ActiveStorage::DiskController.serve_file 触发了错误。是不是 ActiveStorage 应用程序没有正常关闭？
我正在使用 active_storage.service = :test 配置，但 :file 给出了同样的错误。
图像损坏
虽然测试失败，但我可以在 "remote controlled" 浏览器中看到图像没有显示，而是有一个损坏的图像图标。
运行 测试
有一组 4 个特色测试正在通过 "products/_form" 部分的渲染。当我 运行 以随机顺序进行 4 次测试时，错误随机发生。有时我可以看到错误 2 次，有时 3 次。
当我 运行 单独测试时，错误永远不会出现。
我如何附上图片
这是我在进行测试之前用来将文件附加到模型的助手：
path = Rails.root.join 'spec', 'support', 'fixtures', 'img1.png'
raise 'Image does not exist' unless File.exist? path
product.image.attach io: File.open(path), filename: 'image.png'
我也试过用这个助手:
path = Rails.root.join 'spec', 'support', 'fixtures', 'img1.png'
raise 'Image does not exist' unless File.exist? path
blob = ActiveStorage::Blob.create_after_upload! io: path.open, \
filename: 'img1.png', content_type: 'image/png'
product.images.attach blob
还有这个帮手：
path = Rails.root.join 'spec', 'support', 'fixtures', 'img1.png'
raise 'Image does not exist' unless File.exist? path
byte_size = path.size
checksum = Digest::MD5.file(path).base64digest
blob = ActiveStorage::Blob.create_before_direct_upload!(filename: 'img1.png', \
byte_size: byte_size, checksum: checksum, content_type: 'image/png').tap do |blob|
ActiveStorage::Blob.service.upload(blob.key, path.open)
end
product.images.attach blob
系统配置
Rails 版本: 5.2.2
Ruby 版本：ruby 2.5.3p105（2018-10-18 修订版 65156）[x86_64-linux]
Rbenv 版本：rbenv 1.1.1-39-g59785f6
Rspec 相关版本: rspec 3.8.0 - 水豚 3.12.0 - selenium-webdriver 3.141.0
完整跟踪
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/file.rb:63:in `mtime'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/file.rb:63:in `serving'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activestorage-5.2.2/app/controllers/active_storage/disk_controller.rb:42:in `serve_file'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activestorage-5.2.2/app/controllers/active_storage/disk_controller.rb:12:in `show'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_controller/metal/basic_implicit_render.rb:6:in `send_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/abstract_controller/base.rb:194:in `process_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_controller/metal/rendering.rb:30:in `process_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/abstract_controller/callbacks.rb:42:in `block in process_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activesupport-5.2.2/lib/active_support/callbacks.rb:132:in `run_callbacks'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/abstract_controller/callbacks.rb:41:in `process_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_controller/metal/rescue.rb:22:in `process_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_controller/metal/instrumentation.rb:34:in `block in process_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activesupport-5.2.2/lib/active_support/notifications.rb:168:in `block in instrument'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activesupport-5.2.2/lib/active_support/notifications/instrumenter.rb:23:in `instrument'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activesupport-5.2.2/lib/active_support/notifications.rb:168:in `instrument'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_controller/metal/instrumentation.rb:32:in `process_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_controller/metal/params_wrapper.rb:256:in `process_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activerecord-5.2.2/lib/active_record/railties/controller_runtime.rb:24:in `process_action'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/abstract_controller/base.rb:134:in `process'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionview-5.2.2/lib/action_view/rendering.rb:32:in `process'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_controller/metal.rb:191:in `dispatch'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_controller/metal.rb:252:in `dispatch'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/routing/route_set.rb:52:in `dispatch'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/routing/route_set.rb:34:in `serve'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/journey/router.rb:52:in `block in serve'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/journey/router.rb:35:in `each'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/journey/router.rb:35:in `serve'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/routing/route_set.rb:840:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/tempfile_reaper.rb:15:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/etag.rb:25:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/conditional_get.rb:25:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/head.rb:12:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/http/content_security_policy.rb:18:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/session/abstract/id.rb:232:in `context'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/session/abstract/id.rb:226:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/middleware/cookies.rb:670:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activesupport-5.2.2/lib/active_support/callbacks.rb:98:in `run_callbacks'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/middleware/callbacks.rb:26:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/middleware/debug_exceptions.rb:61:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/middleware/show_exceptions.rb:33:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/railties-5.2.2/lib/rails/rack/logger.rb:38:in `call_app'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/railties-5.2.2/lib/rails/rack/logger.rb:26:in `block in call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activesupport-5.2.2/lib/active_support/tagged_logging.rb:71:in `block in tagged'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activesupport-5.2.2/lib/active_support/tagged_logging.rb:28:in `tagged'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activesupport-5.2.2/lib/active_support/tagged_logging.rb:71:in `tagged'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/railties-5.2.2/lib/rails/rack/logger.rb:26:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/middleware/remote_ip.rb:81:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/middleware/request_id.rb:27:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/method_override.rb:22:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/runtime.rb:22:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/activesupport-5.2.2/lib/active_support/cache/strategy/local_cache_middleware.rb:29:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/middleware/executor.rb:14:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/actionpack-5.2.2/lib/action_dispatch/middleware/static.rb:127:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/sendfile.rb:111:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/railties-5.2.2/lib/rails/engine.rb:524:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/urlmap.rb:68:in `block in call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/urlmap.rb:53:in `each'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/rack-2.0.6/lib/rack/urlmap.rb:53:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/capybara-3.12.0/lib/capybara/server/middleware.rb:48:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/puma-3.12.0/lib/puma/configuration.rb:225:in `call'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/puma-3.12.0/lib/puma/server.rb:658:in `handle_request'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/puma-3.12.0/lib/puma/server.rb:472:in `process_client'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/puma-3.12.0/lib/puma/server.rb:332:in `block in run'
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/puma-3.12.0/lib/puma/thread_pool.rb:133:in `block in spawn_thread'
#
# Showing full backtrace because every line was filtered out.
# See docs for RSpec::Configuration#backtrace_exclusion_patterns and
# RSpec::Configuration#backtrace_inclusion_patterns for more information.
# ------------------
# --- Caused by: ---
# Capybara::CapybaraError:
# Your application server raised an error - It has been raised in your test code because Capybara.raise_server_errors == true
# /opt/rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/capybara-3.12.0/lib/capybara/session.rb:147:in `raise_server_error!'
更新
（抱歉失言，我有急事要处理）
这是一个有趣的信息。我在this line之后插入了这个代码：puts "SERVING #{path} - Exist ? #{File.exist? path}"
这是输出（观察文件名和每行末尾的布尔值）：
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/Me/GK/MeGKkqgbb7Sg4RbPoCYWR6pZ - Exist ? true
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/sG/3v/sG3vd2viGWmaf69pNXSChZPa - Exist ? true
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/fy/2C/fy2C8PpaR96YgCzwt5WVBLrQ - Exist ? true
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/sG/3v/sG3vd2viGWmaf69pNXSChZPa - Exist ? true
. (green dot)
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/Me/GK/MeGKkqgbb7Sg4RbPoCYWR6pZ - Exist ? false
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/sG/3v/sG3vd2viGWmaf69pNXSChZPa - Exist ? false
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/Me/GK/MeGKkqgbb7Sg4RbPoCYWR6pZ - Exist ? false
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/fy/2C/fy2C8PpaR96YgCzwt5WVBLrQ - Exist ? false
F (red F)
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/Me/GK/MeGKkqgbb7Sg4RbPoCYWR6pZ - Exist ? false
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/sG/3v/sG3vd2viGWmaf69pNXSChZPa - Exist ? false
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/Me/GK/MeGKkqgbb7Sg4RbPoCYWR6pZ - Exist ? false
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/fy/2C/fy2C8PpaR96YgCzwt5WVBLrQ - Exist ? false
F (red F)
SERVING /tmp/active_storage_tests20190129-10797-1rebdf7/Tx/DL/TxDLPEk3ykf8ETkURY5YZPgY - Exist ? true
正如我们所见，文件路径是相同的，即使在测试之间也是如此。每次测试之间都会清理数据库。所以有 "somewhere" 保存文件校验和的地方，以便 activestorage 重用相同的 blob 记录。结果它重用了相同的文件路径，这就是我遇到 FileNotFound 错误的原因。
有什么想法吗？请注意，除了 DatabaseCleaner 之外，我还有一个像这样定义的后块：
config.after(:each) do
ActiveStorage::Current.reset
ActiveStorage::Attachment.all.each(&:delete)
ActiveStorage::Blob.all.each(&:delete)
end
我怀疑有错误
已填写 PR 并申请重现 https://github.com/rails/rails/issues/34989
等待他们的回应
我不确定你的意思是测试后发生异常？
测试通常应该是原子的和独立的，因此您创建的所有资源都应该在测试完成后立即删除。 此外，测试 运行 以随机顺序排列，因此相互依赖的测试有时会失败 - 有时不会失败，具体取决于 运行 顺序。
你能分享失败的输出或测试吗？
您设置测试图像的方式可能有问题。您可能希望将其更新为 Rails 团队在他们自己的测试中处理它的方式：
module ActiveStorageHelpers
# ported from https://github.com/rails/rails/blob/5-2-stable/activestorage/test/test_helper.rb#L57
def create_file_blob(filename: "image.jpg", content_type: "image/jpeg", metadata: nil)
ActiveStorage::Blob.create_after_upload! io: file_fixture(filename).open, filename: filename, content_type: content_type, metadata: metadata
end
end
RSpec.configure do |config|
config.include ActiveStorageHelpers
end
然后在 spec/fixtures/file/images.jpg 中放置一个小图像文件（file_fixture 方法将在此处查找它）。
设置好后，您可以在功能测试中使用类似以下内容在模型上设置图像：
instance_of_model.images.attach(create_file_blob)
测试通过的事实仅意味着测试不依赖于找到的图像。损坏的图像 link 通常不会导致测试失败，事实上，通常情况下，测试编写者甚至懒得提供模拟图像，因为它（被认为）工作量太大而且与测试无关正在测试的东西。
各位看官，这就是我们ask for an example. Now that the OP has posted an example的原因，可以看出他的问题是浏览器缓存问题，通过更换
来解决product.images.attach io: File.open(path), filename: 'image.png'
和
product.images.attach io: File.open(path), filename: "image-#{Time.now.strftime("%s%L")}.png"
在执行附件的助手中。如果没有这个例子，我不会解决这个问题。
说明
ActiveStorage 处理文件的保存和服务。 OP 用它来保存和提供图像，这绝对是它的目的。为了允许不同的服务以不同的方式提供文件，ActiveStorage 将发布的 URL 与实际的图像服务 URL.
分开已发布的 URL 几乎是永久的link：它是附件数据库密钥的编码版本。 ActiveStorage 通过查找文件的存储位置并将 302 临时重定向发送到可用于访问文件的 URL 来处理对 URL 的请求，称为 "service URL"。当使用 AWS S3 存储文件时，服务 URL 可以是已签名的 URL，它会很快过期，但仍会将浏览器直接连接到 S3，而不必通过作为中介的 Web 服务器。
默认情况下，服务 URL 有效 5 分钟，ActiveRecord 显式设置
Cache-Control: max-age=300, private
在 302 重定向上。浏览器缓存此重定向响应，在接下来的 5 分钟内，浏览器甚至不会尝试使用或验证已发布的 URL，它会立即将 public URL 替换为缓存的服务 URL.
不幸的是，虽然 public URL 可以预见地重新创建，但服务 URL 是随机生成的，因此当浏览器进行自动重定向时，之前有效的服务 URL 不再有效。解决方案（或解决方法，取决于您的观点）是通过在文件名中包含时间戳来区分 public URL，这样测试就不会重复使用 public URLs.
旁注
顺便说一句，您不应该将 url_for 与 image_tag 一起使用。将您的 ERB 更改为
= image_tag url_for(product.image.variant(resize: "120x120"))
至
= image_tag(product.image.variant(resize: "120x120"))
Rails 足够聪明，可以处理任何一种情况，但后一种方式是推荐的方式。