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The secret to coding with confidenceTest Driven Development

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What is TDD? Getting into the habit of writing tests before

writing code.

TDD are continuousshort cycle of test, code,refactor.

Test cases are in separate files. No more print_r &

var_dump in your code!

The tests contain assertions that are either true or

false. Passing the tests confirms correct behavior

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What is TDD? Old way:

Write code first, test if you have time.

Often times, you'll be too exhausted (mentally)

at the end of coding process to write tests.

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What is TDD?

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What is TDD?

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What is TDD?

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What is TDD?

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Why TDD?

TDD gives you higher confidence that your

code is doing what it's suppose to.

Small wins makes the coding process more

enjoyable (Gamification).

Working code every step of the way!

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TDD Process

1 Feature

specifications

2 Write test cases

3 Tests will fail

4 Write code to pass

the tests (minimal)

5 Pass all tests

6 Refactor

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TDD Process

By focusing on writing only the code necessary to

pass tests, designs can be cleaner and clearer than

is often achieved by other methods.

Resist the urge to pre-optimize the code. Just make

it pass first.

Too many asserts might be a sign that your function

is doing too many things - break it into smaller

chunks.

No code is perfect.

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Benefits

Detect if other parts of your app is affected bythe latest code change.

Coverage reports help you discover potentialweak spots / blind spots in your code.

Tests with examples will help in simulating

actual use cases in an automated manner.

Tests becomes the documentation.

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Adoption Strategies Legacy Codebase

Identify critical path, generate skeleton test

cases & write test cases.

Write tests for new features &/or code that

are accessed by the new feature.

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Adoption Strategies New Projects

Establish a workflow and make the

automated test part of your release process.

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Adoption Strategies

Developers who write their own tests mighthave a tendency to take shortcuts by writingconservative test cases.

One way to prevent this is to pair-program withanother developer or a product owner whenpreparing the test cases.

Spec documents that includes examples canbe useful to validate code behavior.

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PHPUnit is the de-facto standard for unit

testing in PHP projects. It provides both aframework that makes the writing of tests easy

as well as the functionality to easily run the

tests and analyse their results.

http://phpunit.de

Created by Sebastian Bergmann

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http://phpunit.de/http://phpunit.de/http://phpunit.de/http://phpunit.de/

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Demo

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Demo Script

Installing PHPUnit.

Use existing class to generate tests.

Use test cases to generate class file.

Coverage Report.

Behavior Driven Development.

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Installing PHPUnit

# pear config-set auto_discover 1

# pear install pear.phpunit.de/PHPUnit

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Sample Code

https://github.com/miccheng/TDD-PHP-Sample

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Behavior Driven

Development (BDD) Not just testing individual units, but testing the

codes as a user would use your app (ie. how

diff parts of your code work together).

Process is the same, just that the tests are

story-based.

User stories = Specs with examples

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Caveat

It's gonna take some time to get productive

Read: Downtime of at least 1-2 days

Nothing is full-proof!

It's easy to get lured into a false sense of security.

Even if u have 100% coverage, it still doesn'tprevent unintended usage from breaking the code.

Bugs are test cases you have not written yet.

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