NodeJS: Writing tests -- A Beginners' Guide

NodeJS:
Writing Tests
A Beginners’ Guide
Docs: http://conancat.github.com/node-test-examples/
Github: https://github.com/conancat/node-test-examples

Prepared by Grey Ang
@conancat | conancat@gmail.com

Wednesday, April 3, 13

Why write tests?


Programming should be fun


...and not
frustrating.


The biggest joy in
programming is knowing
what you write does
what it intended to do,
and it doesn’t break
anything else.


We all want a peace of
mind. Nirvana.


...but we’re all lazy asses.
Trust me, I know. I am one too.


Most common excuses to
not write tests
Laziness: “Writing tests is such a chore!”

Perceived busyness: “We have too many things to
do! We have other targets to hit!”

Overconﬁdence: “This function is really easy. I can
handle this.”

Ego: “Come on, real men doesn’t need to test their
code. It’ll deﬁnitely work. Trust me, I’m a
programmer.”


What are the
consequences?


96% of programmers do this to their
computers at least once a week.

(Okay, I made up that number.
But we all know how that feels.)


Shit programmers deal with
Old code breaks when Your code just broke other
you write new code people’s code

Code that you wrote is You spend 8 hours
slow as hell debugging your code and
other people’s code
What you’ve done is not
what it supposed to do ...to name a few.


Whose fault is it?
Yours, of course.


If you’re a true lazy
programmer that doesn’t
wanna deal with all that
shit, write tests.
Mark my words. You won’t regret it.


TDD & BDD
Two jargons you should know
since yesterday


Test Driven
Development (TDD)
“...the developer writes an (initially failing)
automated test case that deﬁnes a desired
improvement or new function, then produces
the minimum amount of code to pass that test,
and ﬁnally refactors the new code to
acceptable standards.”

http://en.wikipedia.org/wiki/Test-driven_development


Test Driven
Development (TDD)
Step 1: Write Test

Step 2: Run the test.
(It will fail, trust me. It’s okay. Take a deep breath. )

Step 3: Write the MINIMUM AMOUNT code to make
the test pass

Step 4: Test performance of code to optimal levels

Step 5: Celebrate that your code works wonderfully

Step 6: Write tests, rinse and repeat.


Problems with traditional TDD
Test cases are written for the code -- not for the
manager, client, or the users of the system.

Code works with the test, code passes the test, but
code FAIL with user behavior or client requirements.

Traditional TDD is great for development. But if we
want code that WORKS, we need to involve the people
who spec the app.

Remember, code is written for the beneﬁt of people!


Introducing
Behavior Driven
Development
It’s just like TDD, really. Only better.


Behavior Driven
Development (BDD)
“...combines the general techniques and
principles of TDD with ideas from domain-
driven design and object-oriented analysis
and design to provide software developers
and business analysts with shared tools and a
shared process to collaborate on software
development.”
http://en.wikipedia.org/wiki/Behavior-driven_development


Behavior Driven
Development (BDD)
Step 1: Gather (and argue) requirements from the business side
or your users on what should be done

Step 2: Write test cases to meet the pre-deﬁned business
requirements

Step 3: Write the MINIMUM AMOUNT code to make the test
pass

Step 4: Show it to your business partner

Step 5: ???

Step 6: Proﬁt!


“With great power,
comes great
responsibility.”
-- Uncle Ben, Spiderman


You’re a web developer.
You make websites.

You’re Spiderman.
Remember, you work with machines AND people.
You write code for people.


4 Test Situations
that we’ll be doing today

Functional and module testing

Handling database calls

Testing REST API layers

Headless browser testing


Best way to learn is by
doing it yourself.
So, lift your lazy ass and go clone this repo
and start playing around.

https://github.com/conancat/node-test-examples


Need help? SHOUT!
Or you can just talk to me at
@conancat on Twitter, or email me at
conancat@gmail.com.


Thanks for coming!
Be a good Spiderman!


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