上传文件存根的 Rails 5 rspec 测试失败

Question

在我上传文件的 rspec 中，我正在存根这样的函数：

 allow(ABCCLass::XYZProcessor).to receive(:prepare_processing).with(csv_statements).and_return(nil)

和

let(:csv_statements) do
 [fixture_file_upload('transaction.csv', 'application/csv')]
end

我得到错误期望： 预期 Rack::Test::UploadedFile 得到 ActionDispatch::Http::UploadedFile

这完全有道理，因为 fixture_file_upload 返回 Rack::Test::UploadedFile 并用它生成存根，但在控制器上传的文件中是 Action::Dispatch::Uploaded 文件的实例。

知道如何创建存根并解决此问题吗？

回溯：

-[[#<Rack::Test::UploadedFile:0x00559d3f298100 @content_type="application/csv", @original_filename="blank.csv", @tempfile=#<Tempfile:/tmp/blank.csv20180114-293-jcb2ii>, @_filename="eur-transactions.csv">,
   -  #<Rack::Test::UploadedFile:0x00559d3f296e40 @content_type="application/csv", @original_filename="blank.csv", @tempfile=#<Tempfile:/tmp/blank.csv20180114-293-1xbpd0t>, @_filename="gbp-statement.csv">,
   -  #<Rack::Test::UploadedFile:0x00559d3f295e50 @content_type="application/csv", @original_filename="blank.csv", @tempfile=#<Tempfile:/tmp/blank.csv20180114-293-1peng22>, @_filename="internal_HSBCnet1.xls">]]
   +[[#<ActionDispatch::Http::UploadedFile:0x00559d3cb3a6a8 @tempfile=#<Tempfile:/tmp/RackMultipart20180114-293-1l9ma69.csv>, @original_filename="eur-transactions.csv", @content_type="application/csv", @headers="Content-Disposition: form-data; name=\"bank_statements[]\"; filename=\"eur-transactions.csv\"\r\nContent-Type: application/csv\r\nContent-Length: 0\r\n">,
   +  #<ActionDispatch::Http::UploadedFile:0x00559d3cb3a608 @tempfile=#<Tempfile:/tmp/RackMultipart20180114-293-17oxrrk.csv>, @original_filename="gbp-statement.csv", @content_type="application/csv", @headers="Content-Disposition: form-data; name=\"bank_statements[]\"; filename=\"gbp-statement.csv\"\r\nContent-Type: application/csv\r\nContent-Length: 0\r\n">,
   +  #<ActionDispatch::Http::UploadedFile:0x00559d3cb3a568 @tempfile=#<Tempfile:/tmp/RackMultipart20180114-293-2ukuul.xls>, @original_filename="internal_HSBCnet1.xls", @content_type="application/csv", @headers="Content-Disposition: form-data; name=\"bank_statements[]\"; filename=\"internal_HSBCnet1.xls\"\r\nContent-Type: application/csv\r\nContent-Length: 0\r\n">]]

    Please stub a default value first if message might be received with other args as well. 
 # /root/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/rspec-support-3.7.0/lib/rspec/support.rb:97:in `block in <module:Support>'
 # /root/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/rspec-support-3.7.0/lib/rspec/support.rb:106:in `call'
 # /root/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/rspec-support-3.7.0/lib/rspec/support.rb:106:in `notify_failure'
 # /root/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/rspec-mocks-3.7.0/lib/rspec/mocks/error_generator.rb:327:in `notify'
 # /root/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/rspec-mocks-3.7.0/lib/rspec/mocks/error_generator.rb:311:in `__raise'
 # /root/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/rspec-mocks-3.7.0/lib/rspec/mocks/error_generator.rb:60:in `raise_missing_default_stub_error'
 # /root/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/rspec-mocks-3.7.0/lib/rspec/mocks/proxy.rb:206:in `raise_missing_default_stub_error'
 # /root/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/rspec-mocks-3.7.0/lib/rspec/mocks/proxy.rb:191:in `message_received'
 # /root/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/rspec-mocks-3.7.0/lib/rspec/mocks/proxy.rb:326:in `message_received'
 # /root/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/rspec-mocks-3.7.0/lib/rspec/mocks/method_double.rb:77:in `proxy_method_invoked'
 # /root/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/rspec-mocks-3.7.0/lib/rspec/mocks/method_double.rb:64:in `block (2 levels) in define_proxy_method'
 # ./app/controllers/admin/daily_adjustments/bank_transfer_deposits_controller.rb:25:in `start_process'

Answer 1

一个老问题，但是我最近遇到了这个问题，我正在测试正确的参数是否被传递给另一个类，包括上传的 csv 文件。

解决方法是存根ActionDispatch::Http::UploadedFile 并让其:new 方法返回fixture_file_upload 创建的Rack::Test::UploadedFile: 实例。

let(:csv_file) do
  path = Rails.root.join('spec', 'fixtures', 'test.csv')
  fixture_file_upload(path, 'text/csv')
end

before do
  allow(ActionDispatch::Http::UploadedFile).to receive(:new)
    .and_return(csv_file)
end

it 'passes csv file to class' do
  perform
  expect(MyClass).to have_received(:new).once.with(file: csv_file)
end

Answer 2

不要在测试中调用fixture_file_upload('transaction.csv', 'application/csv')，而应该使用该返回值。

如果你想存根它，我会使用一个实例双精度。比如：

let(:csv_statements) { instance_double(Rack::Test::UploadedFile, content_type: 'application/csv', original_filename: 'blank.csv', file_name: 'eur-transactions.csv') }

这可能无法通过复制和粘贴来工作，但这将存根该类的一个实例，并且每当收到这些消息时，它都会返回这些值。我不知道“fixture_file_upload”内部发生了什么，但是无论返回 Rack::Test::UploadedFile 对象，只要像这样存根即可。如果你想做一个类存根，它非常相似：

let(:csv_statements) { class_double(Rack::Test::UploadedFile, content_type: 'application/csv', original_filename: 'blank.csv', file_name: 'eur-transactions.csv').as_stubbed_const }

Answer 3

解决方案是使用ActionDispatch::Http::UploadedFile 生成存根，目的是匹配实际函数的签名和参数。