Introducing the Lindo (response_visualizer) plugin for Rails

Being at RubyConf this weekend has provided the necessary motivation for me to finally release a new Ruby gem I’ve been building. It’s an extraction from a project I’ve been working on for Relevance.

I’m a regular user of assert_select in my functional tests. I find myself frequently doing something like this when the assertion is failing and I can’t figure out why:

def test_something
  post :something
  raise @response.body.inspect
  assert_select "div[id=header]"
end

Inspecting the response body usually leads me to a solution, but it’s tedious parsing through the huge amount of HTML that gets returned, often in a semi-unreadable format. Enter the response_visualizer plugin (which has since been renamed Lindo):

script/plugin install http://github.com/adeptware/lindo/

Or clone the project directly:

git clone http://github.com/adeptware/lindo/

The plugin provides a vr method to your functional tests. When this method is called, the response body is automatically opened in the default browser allowing for easy visual inspection of the page’s content:

post :new
vr
...

If you’d prefer to jump straight to the source code, passing the :html symbol will open the formatted HTML in the default text editor:

post :new
vr(:html)
...

This has saved me a lot of time in figuring out why a specific assertion is failing. Instead of parsing through the HTML, I can view the entire page and immediately tell if something is missing or out of place. I find myself calling vr even before I write my assertions now.

After installing, check out the README file for additional documentation. There is also a GitHub project if you’d like to contribute a patch or fork the code. Enjoy!