Testing against an api

Ruby
1

When testing code that consumes a web service, is it bad for the
tests/specs to actually hit the api, or should the get/post/whatever
requests be stubbed out?

I’m currently writing a Ruby gem for a particular micro-blogging api. My
tests actually make requests against the api and I was just wondering if
maybe I shouldn’t be doing that…

2

On Fri, Jan 23, 2009 at 5:38 PM, Brent C. [email protected]
wrote:

Two reasons you shouldn’t

  1. It slows down your tests which means your run them less often or stop
    testing eventually
  2. Your calls will be directly affecting the remote service and actually
    creating, modifying or deleting things in the process (not usually what
    you
    want to do while testing)

–
Andrew T.
http://ramblingsonrails.com
http://www.linkedin.com/in/andrewtimberlake

“I have never let my schooling interfere with my education” - Mark Twain

3

Brent C. wrote:

When testing code that consumes a web service, is it bad for the
tests/specs to actually hit the api, or should the get/post/whatever
requests be stubbed out?

Two reasons it’s bad. The first is a simple rule “never hit the wire at
test
time”. It annoys the remote server, and exposes your test runs to false
negatives if that server is down (or when it finally blacklists your
development
workstation!).

The other rule is Mike Feathers’s guideline for testing: “Test cases
should
never touch the file system, the database, or the wires.” That’s not a
rule,
it’s just a head-game to encourage his disciples to decouple their code
and
improve its isolation and encapsulation. Intermediate logic code should
not have
runaway dependencies on low-level code with side-effects.

I’m currently writing a Ruby gem for a particular micro-blogging api. My
tests actually make requests against the api and I was just wondering if
maybe I shouldn’t be doing that…

Run those tests one last time, with p statements that barf out the
low-level
responses as strings.

Use Mocha to mock the HTTP::Post activity (or whatever), and copy those
tests
into the .returns(). Then run your tests with your network wire
unplugged (yes,
and take a long uneasy break from twitter, boingboing, apod, chat,
google, RSS,
and this newsgroup!), and make sure all your tests still pass.

4

Check out fakeweb which can be used to help mock out your web service
calls
easily:
http://technicalpickles.com/posts/stop-net-http-dead-in-its-tracks-with-fakeweb

Matt

On Fri, Jan 23, 2009 at 2:13 PM, Phlip [email protected] wrote:

development workstation!).

–
Phlip

–
Matt T.
Highgroove Studios
www.highgroove.com
cell: 404-314-2612
blog: maraby.org

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