运行功能Rspecs时，出现以下错误（此消息底部的完整跟踪）
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)
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)
product.image是一个ActiveStorage附件。在测试期间，将渲染“ products / _form”部分，并显示带有以下代码的附件文件（即png图像）：= image_tag url_for(product.image.variant(resize: "120x120"))。如果我注释掉这一行，就不会再出现该错误。
测试本身每次都成功，该错误似乎是在测试后触发的。我验证了我所有的after程序段，似乎是在所有后续程序段之后发生的。
跟踪表明ActiveStorage::DiskController.serve_file触发了错误。是ActiveStorage应用程序没有正常关闭吗？
我正在使用active_storage.service = :test配置，但是:file给出了相同的错误。
测试失败时，我可以在“远程控制”浏览器中看到该图像未显示，而是有一个损坏的图像图标。
有一组4个功能测试正在通过“ products / _form”部分的呈现。当我以随机顺序运行这4个测试时，错误会随机发生。有时我可以看到2次错误，有时是3次。
当我单独运行测试时，错误永远不会出现。
这是我在通过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'
我也尝试使用此助手：
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
这个助手：
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
发布版本：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-capybara 3.12.0-selenium-webdriver 3.141.0
# /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!'
（很抱歉，我保持沉默，我有紧急情况要参加）
这是一个有趣的信息。我在this line之后插入了此代码：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
我们可以看到，即使在两次测试之间，文件路径也相同。在每次测试之间都要清除数据库的内容。因此，存在“某处”保留文件校验和，以便主动存储重用相同的Blob记录。结果，它重用了相同的文件路径，这就是为什么我出现FileNotFound错误的原因。
有什么主意吗？请注意，除了DatabaseCleaner之外，我还有一个after块，定义如下：
config.after(:each) do
ActiveStorage::Current.reset
ActiveStorage::Attachment.all.each(&:delete)
ActiveStorage::Blob.all.each(&:delete)
end
在PR中添加了用于复制https://github.com/rails/rails/issues/34989的应用程序
等待他们的回应
答案 0 :(得分：3)
如何设置要测试的图像可能会出错。您可能想将其更新为Rails团队在自己的测试中如何处理它：
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（这是file_fixture方法将在其中寻找它的地方）中放置一个很小的图像文件。
将其放置在适当的位置后，您可以在功能测试中通过以下方式在模型上设置图像：
instance_of_model.images.attach(create_file_blob)
答案 1 :(得分：1)
测试通过的事实仅表示测试不依赖于所找到的图像。断开的图像链接通常不会导致测试失败，事实上，通常情况下，测试编写者甚至不费心提供模拟图像，因为（认为是）它工作量太大，并且与被测对象无关
再见，这就是我们ask for an example的原因。现在OP具有posted an example，我们可以看到他的问题是浏览器缓存，并且将通过替换来解决
product.images.attach io: File.open(path), filename: 'image.png'
使用
product.images.attach io: File.open(path), filename: "image-#{Time.now.strftime("%s%L")}.png"
在执行附件的助手中。如果没有示例，我将无法解决。
ActiveStorage处理保存和提供文件。 OP正在使用它来保存和提供图像，这绝对是它的初衷。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与实际的图像提供URL分开。
已发布的URL几乎是一个永久链接：它是附件的数据库密钥的编码版本。 ActiveStorage通过查找文件的存储位置并发送302临时重定向到可用于访问文件的URL（称为“服务URL”）来处理对URL的请求。使用AWS S3存储文件时，服务URL可以是快速过期的已签名URL，但仍将浏览器直接连接到S3，而不必作为中介通过Web服务器。
默认情况下，服务URL会持续5分钟，并且ActiveRecord会明确设置
Cache-Control: max-age=300, private
在302重定向上。浏览器会缓存此重定向响应，并且在接下来的5分钟内，浏览器甚至不会尝试使用或验证已发布的URL，它将立即用缓存的服务URL替换公共URL。
不幸的是，虽然可以预见地重新创建了公共URL，但是会随机生成服务URL，因此当浏览器进行自动重定向时，先前有效的服务URL将不再起作用。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公共URL，以便测试不会重用公共URL。
边注
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"))
到
= image_tag(product.image.variant(resize: "120x120"))
Rails足够聪明，可以处理任何一种情况，但推荐使用后一种方法。
答案 2 :(得分：0)
我不确定您的意思是异常会在测试后发生吗？
测试通常应该是原子的且独立的，因此您创建的所有资源都应在测试完成后立即删除。 另外，测试是以随机顺序运行的，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。
您可以共享失败的输出或测试吗？