Shabnam Shahfar

@ShabnamShahfar

Prairie Dev Con, 2014Protegra

What is a unit test?

Test Driven Development

Running a unit test in a browser

Libraries and Frameworks

Writing Testable JavaScript

Exercise/Demo

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A test for the smallest testable part of your application

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Isolated and Independent

Repeatable

Small

Easy to read

Fast

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Find problems early

Develop & refactor with confidence

Easier than testing manually

Documentation

On-going Regression Testing

Better Design

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“Do the pieces work together as expected?”

Simulate user’s behavior

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They don’t help you write better code, they just make sure your application still works.

Slower than unit testing

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Block Scope vs. Function Scope

Proxy Objects

Simulating DOM Events

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Function scope also means that variables declared inside functions are only available inside those functions, once the function exits, the variables are inaccessible.

JavaScript does have private variables. You declare them inside closures.

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Block Scope vs. Function Scope

Proxy Objects

Simulating DOM Events

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Block Scope vs. Function Scope

Proxy Objects

Simulating DOM Events

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Example

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Code organization

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Presentation & Interaction

Application State

Data/Server Communication

Setup

Anonymous functions, lack of structure

Complex, oversized functions

Hidden or shared state

Tightly coupled

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Keep methods simple

Don’t intermingle responsibilities

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Write test first!

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Books:

JavaScript the good parts, by Douglas Crockford

JavaScript unit testing, by Hazem Saleh

http://alistapart.com/article/writing-testable-javascript

http://www.adequatelygood.com/Writing-Testable-JavaScript.html

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