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Christopher Haupt
Recently, I needed to write my first set of functional tests for a form that is used to upload image assets into our Content Management System. I wanted to find something as easy as fixtures for testing this part of our program.
<p>Recently, I needed to write my first set of functional tests for a form that is used to upload image assets into our Content Management System. I wanted to find something as easy as fixtures for testing this part of our program.</p>
<p>Whether you are using <a href="http://techno-weenie.net/">Rick Olson’s</a> excellent attachment_fu (see <a href="http://clarkware.com/cgi/blosxom/2007/02/24">Mike Clark’s nice tutorial</a>), <a href="http://uploadcolumn.rubyforge.org/">Sebastian Kanthak and Jonas Nicklas’ upload_column</a>, or your own code that works with file uploads, you should test this workflow just like any other code path. At first, I thought this was going to be a painful task and require messing around with some custom File I/O or other marshaling trickery. Most of the documentation for 3rd party file upload implementations tended to have little or no information on testing.</p>
<p>Then, while reading through the code a bit more, I stumbled upon <a href="http://api.rubyonrails.org/classes/ActionController/TestProcess.html">fixture_file_upload</a>. This convenience function is tucked away in ActionController’s TestProcess module and is shorthand for instantiating the underlying ActionController::TestUploadedFile class. TestUploadedFile itself is a mock object that simulates the target file that my user would upload in a form or other interface via a <span class="caps">MIME</span> multipart/form-data <span class="caps">POST</span>.</p>
<p>To use this handy method, I simply put test files in a convenient directory within my fixtures directory, say “files”. Then in a test for upload_column, I write:</p>
<pre>
def test_should_create_asset
old_count = Asset.count
post :create, :asset => { :title => "test", :file => fixture_file_upload('/files/testpicture1.jpg', 'image/jpeg') }
assert_equal old_count+1, Asset.count
assert_redirected_to asset_path(assigns(:asset))
end
</pre>
<p>Here, the :file attribute for my asset model is expecting an uploaded file from my form, so I feed it one from my fixtures/files directory.</p>
<p>If I use attachment_fu, I may write a create test:</p>
<pre>
def test_should_create_asset
old_count = Asset.count
post :create, :asset => { :name => 'railslogo', :uploaded_data => fixture_file_upload('/files/rails.png', 'image/png') },
:html => {:multipart => true }
assert_equal old_count+1, Asset.count
end
</pre>
<p>or an update test:</p>
<pre>
def test_should_update_asset
put :update, {:id => assets(:one).id, :asset => { :uploaded_data => fixture_file_upload('/files/rails.png', 'image/png') }}
assert_redirected_to asset_path(assigns(:asset))
end
</pre>
<p>The TestUploadedFile class is not limited to image data. It can channel any type I may wish into the request. Its default content type assumes text/plain.</p>
<p>Now I can proceed to write a suite of tests for my file upload use cases and let Action Controller and the fixture_file_upload helper do the heavy lifting.</p>
<h3>Other Resources</h3>
<ul>
<li><a href="http://www.subelsky.com/2007/05/functional-testing-for-attachment-fu.html">Mike Subelsky’s Blog Entry about testing Attachment_fu</a></li>
<li><a href="http://www.beckshome.com/PermaLink,guid,560613dd-217c-4cb1-a6b9-df83a55191e7.aspx">Thomas Beck’s Blog Entry about multi-model tests with Attachment_fu</a></li>
</ul>
2008-07-24T01:00:47-07:00
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File Upload Form Testing Fixtures
2008-02-04T16:00:00-08:00
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2009-03-19T11:30:40-07:00
1
1
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