CODEWITHSUNDEEP
rubycommand-linecucumberintegration-testing
xiy
xiy

Reputation: 878

What is the best way to simulate no Internet connection within a Cucumber test?

Part of my command-line Ruby program involves checking if there is an internet connection before any commands are processed. The actual check in the program is trivial (using Socket::TCPSocket), but I'm trying to test this behaviour in Cucumber for an integration test.

The code:

def self.has_internet?(force = nil)
  if !force.nil? then return force
  begin
    TCPSocket.new('www.yelp.co.uk', 80)
    return true
  rescue SocketError
    return false
  end
end

if has_internet? == false
  puts("Could not connect to the Internet!")
  exit 2
end

The feature:

Scenario: Failing to log in due to no Internet connection
  Given the Internet is down
  When I run `login <email_address> <password>`
  Then the exit status should be 2
  And the output should contain "Could not connect to the Internet!"

I obviously don't want to change the implementation to fit the test, and I require all my scenarios to pass. Clearly if there is actually no connection, the test passes as it is, but my other tests fail as they require a connection.

My question: How can I test for this in a valid way and have all my tests pass?

Upvotes: 5

Views: 1040

Answers (3)

Mischa Molhoek
Mischa Molhoek

Reputation: 164

maybe a bit late for you :), but have a look at

https://github.com/mmolhoek/vcr-uri-catcher

I made this to test network failures, so this should do the trick for you.

Upvotes: 0

Flexoid
Flexoid

Reputation: 4245

You can stub your has_internet? method and return false in the implementation of the Given the Internet is down step.

YourClass.stub!(:has_internet?).and_return(false)

Upvotes: 4

Michael Slade
Michael Slade

Reputation: 13877

There are three alternative solutions I can think of:

  1. have the test temporarily monkeypatch TCPSocket.initialize (or maybe Socket#connect, if that's where it ends up) to pretend the internet is down.
  2. write (suid) a script that adds/removes an iptables firewall rule to disable the internet, and have your test call the script
  3. use LD_PRELOAD on a specially written .so shared library that overrides the connect C call. This is harder.

Myself, I would probably try option 1, give up after about 5 minutes and go with option 2.

Upvotes: 1

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