No such file or directory - irb (Errno::ENOENT)

Uhoh! Ever had this error before?

colabus@typhon:~/public_html/rails/workorders# ruby script/console
Loading development environment.
/usr/lib/ruby/gems/1.8/gems/rails-1.1.6/lib/commands/console.rb:25:in `exec': No such file or directory - irb -r irb/completion -r script/../config/../config/environment -r console_app -r console_with_helpers --simple-prompt (Errno::ENOENT)
from /usr/lib/ruby/gems/1.8/gems/rails-1.1.6/lib/commands/console.rb:25
from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:27:in `gem_original_require'
from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:27:in `require'
from /usr/lib/ruby/gems/1.8/gems/activesupport-1.3.1/lib/active_support/dependencies.rb:147:in `require'
from script/console:3

I came across it when I decided to upgrade the Rails 1.2 and installed an updated Ruby version. Took me a little while to work out what was wrong but it seems script/console calls irb and not irb1.8. If you check out the /usr/bin/ directory you'll find the issue. And a simple fix:

# sudo ln -s /usr/bin/irb1.8 /usr/bin/irb

colabus@typhon:~/public_html/rails/workorders# ruby script/console
Loading development environment.
>>

Test validations on model with base

Testing is a fairly simple process for ruby on rails development as it's "baked right in" as Mike Clark would say. But how do we test our validate/validate_on_create/etc methods when our helpers don't quite give us the flexibility we want?

We have our built in validation helpers in the model and we can execute a simple test like below.

Customer model:
validates_presence_of :address

Related test on validation helper:
def test_invalid_with_empty_attributes
customer = Customer.new

assert !customer.valid?
assert customer.errors.invalid?(:address)
end

Now suppose you have the method validate in the ruby on rails model and wish to run a test on it. Or more specifically you want to run a test on the asserted error, "assert_equal".

In our model:
protected
def validate
errors.add_to_base 'You must have at least a business name or first name.' if firstname.blank? and business.blank?
end

In our test:
def test_presence_with_validate
customer = Customer.new(
:business => nil,
:firstname => nil,
:address => "123 House Street"
)

assert !customer.valid?
assert_equal "You must have at least a business name or first name.", customer.errors.on(:base)
end

The trick is the specify :base as the "on" method parameter.

And so we test:
# ruby test/unit/customer_test.rb -n test_presence_with_validate
Loaded suite test/unit/customer_test
Started
.
Finished in 0.057076 seconds.

1 tests, 2 assertions, 0 failures, 0 errors