May 27, 2007

Posted by John

Tagged testing

Older: My Must Read Summary of RailsConf 2007

Newer: Even Edgier Than Edge Rails

assert_difference has morphed

This is just a little note that assert_difference, the ultimate test helper, has been merged into core. The only issue is that it has changed a bit from the version that I have used. I always used something along the lines of:

assert_difference Post, :count do
  Post.create_valid
end

The version that got merged into core instead accepts a string like so:

assert_difference 'Post.count' do
  Post.create_valid
end

Not sure why the syntax is different but that is neither here nor there for me. The only down side is I had to go through all my tests and fix the incorrect arguments. Just thought I would say something here so others know what is going wrong when all their tests fail after upgrading to edge.

3 Comments

  1. Try asserting the difference on post.comments.size with the old syntax and you’ll see why it changed ;)

  2. Well, I trusted that it was for the best. :) Thanks for the example.

  3. I’m using Rails 2.0.1 and the ‘Post.count’ syntax doesn’t seem to be working. I get TypeError: nil is not a symbol. The old syntax works though :-)

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Authored by John Nunemaker (Noo-neh-maker), a web developer and programmer who has fallen deeply in love with Ruby. More about John.

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