David Chelimsky

If you use autotest with rspec or test/unit, you’ve probably had this experience (or one like it):

You want to add some new behaviour to a model object, so you write a spec, watch it fail, make it pass, and then wait until the entire spec suite runs. Even if you’ve got a fast-running suite, this can be painful sometimes.

Wouldn’t it be great if you could limit the scope of what directories autotest observes? Well it turns out that you can! Recent releases of ZenTest include a find_directories attribute on the autotest object. Just add this to your .autotest file:

Autotest.add_hook :initialize do |at|
  unless ARGV.empty?
    at.find_directories = ARGV.dup
  end
end

and then you can say:

autotest app/models spec/models

and it will only observe those directories. This is nice and flexible, but I find that most of the time I’m wanting pairs like that: app/models and spec/models, or app/views/accounts and spec/views/accounts. In that case, I’d really like to just say:

autotest models

To accomplish that you can do this to the hook instead:

Autotest.add_hook :initialize do |at|
  unless ARGV.empty?
    at.find_directories = ["spec/#{ARGV.first}","app/#{ARGV.first}"]
  end
end

Want the best of both worlds? Try this:

Autotest.add_hook :initialize do |at|
  unless ARGV.empty?
    at.find_directories = ARGV.length == 1 ? ["spec/#{ARGV.first}","app/#{ARGV.first}"] : ARGV.dup
  end
end

The only limitation of this is that it’s based on directories, not files. Once in a while, when I’m bootstrapping a new object, I’ll keep the examples and the implementation in the same file until I’ve got things fleshed out a bit the object is ready to play nice with others. In that case, I might like to just point autotest to that one file. I started working on a patch for this for ZenTest, but I’m not sure it’s worth the extra effort. What do you think?

Regardless – happy auto-exemplifying!

The RSpec-1.1.2 release includes changes to keep RSpec compatible with autotest in ZenTest-3.8.0. This new ZenTest release boasts an improved cascading configuration model that works well for subclasses (like those that ship with RSpec) and allows users to override the mappings of specs (or tests) to code as well as the list of files that get ignored by autotest.

To support this, Autotest now loads the following files in the following order:

Autotest
AutotestSubClass
~/.autotest
./.autotest

This allows RSpec (or any other library) to override defaults set in Autotest, and then provides users both generic (~/.autotest) and project specific (./.autotest) control over the mappings and exceptions.

How can you take advantage of this?

When autotest begins to run, it calls its :initialize hook. This hook is exposed by the add_hook method. You can use this to access the mappings and exceptions using the following methods on Autotest:

clear_mappings()
add_mapping(regexp, proc)
remove_mapping(regexp)
 
clear_exceptions()
add_exception(string)
remove_exception(string)

add_mapping

The add_mapping method adds a key/value pair to a hash that maps regexps to procs. Whenever autotest senses that a file is touched, it looks for the regexp that matches the file name and the runs all the files returned by the associated proc.

Imagine you’re working on a shopping cart app. You have some currency conversion behaviour in a Product model that you’d like to extract to an acts_as_currency plugin, and you want autotest to observe the process. You might add a mapping like this to .autotest:

Autotest.add_hook :initialize do |at|
  at.add_mapping(%r%^plugins/acts_as_currency/lib/.*\.rb$%) {
    at.files_matching %r%^spec/models/product_spec\.rb$% +
    at.files_matching %r%^plugins/acts_as_currency/spec/.*_spec\.rb$%
  }
end

In this case, a change to any of the files in the plugin’s lib directory would cause all the plugins specs to run, as well as the spec for the Product model.

add_exception

The add_exception method adds paths to a list of paths that Autotest ignores.

I like to run autotest in verbose mode (autotest -v) because it tells me when I change a file that it doesn’t know what to do with. The drawback is that it wants to tell me every time I commit because files in the .svn/.hg/.git directories change. So I’ve got these all listed as exceptions in my ~/.autotest file, along with assorted others:

Autotest.add_hook :initialize do |at|
  %w{.svn .hg .git}.each {|exception|at.add_exception(exception)}
end

Note that autotest compiles this list to a Regexp with no anchors, so .hgignore and .gitignore would also get ignored in this case.

Cascading config and granular control

One of the coolest changes in ZenTest-3.8.0 is that autotest loads both ~/.autotest and ./.autotest. So now you can have the hooks you like on every project (like growl notifation) all in one place and still have project specific settings.

This also allows you to set up global mappings/exceptions and modify them at the project level. See Autotest’s RDoc for more info.