CODEWITHSUNDEEP
rubyrspec
Erran Morad
Erran Morad

Reputation: 4753

RSpec NoMethodError: "undefined method `describe' for main Object"

I am trying to learn Rspec. My ruby project in eclipse is as follows -

enter image description here

The code-

require 'rspec'
require './RubyOffRailsTuts/classes/furlong'

describe Furlong do
end

The error-

/RubyOffRailsTuts/specs/furlong_spec.rb:6:in `<main>': undefined 
method `describe' for main:Object (NoMethodError)

Did not get any useful answers online. How do I fix this problem ?

Upvotes: 37

Views: 27966

Answers (5)

user513951
user513951

Reputation: 13715

The solution

Call RSpec.describe instead of just describe.

require 'rspec'
require './RubyOffRailsTuts/classes/furlong'

RSpec.describe Furlong do
end

The reason it works

You can tell from the error message "undefined method `describe' for main Object" that the underlying problem is that you are trying to call describe on the the basic Object main, which does not have a describe method.

Upvotes: 43

LE-HU
LE-HU

Reputation: 901

If someone by any chance gets a similar brain blackout for couple minutes like myself a while ago and does use:

ruby spec/yourspec.rb

instead of

rspec spec/yourspec.rb

And is completely stunned why this did work a minute ago and does not right now when nothing has changed - this is exactly the error that pops in.

Upvotes: 2

Tyler Collier
Tyler Collier

Reputation: 11988

I agree with sevenseacat that you're likely using a modern version of RSpec that disables monkey patching.

This disabling is done by default when the spec_helper.rb file is created when you do something like

$ rails generate rspec:install

In spec_helper.rb, you'll see a section that looks like this:

# Limits the available syntax to the non-monkey patched syntax that is
# recommended. For more details, see:
#   - http://myronmars.to/n/dev-blog/2012/06/rspecs-new-expectation-syntax
#   - http://www.teaisaweso.me/blog/2013/05/27/rspecs-new-message-expectation-syntax/
#   - http://myronmars.to/n/dev-blog/2014/05/notable-changes-in-rspec-3#new__config_option_to_disable_rspeccore_monkey_patching
config.disable_monkey_patching!

You can comment out that last line.

However, the recommended approach is not to use monkey patching, and use RSpec.describe.

Upvotes: 20

0xtobit
0xtobit

Reputation: 1141

Alternative to prefacing describe as RSpec.describe, you can add

config.expose_dsl_globally = true

to your spec_helper.rb.

Upvotes: 51

sevenseacat
sevenseacat

Reputation: 25049

You prefix describe with RSpec, eg. RSpec.describe because it sounds like you're using a modern version of RSpec that disables monkey patching.

Upvotes: 23

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