legacy-testing-kata-java

A legacy codebase that resist a bit testing, by Cyrille Martraire.

Original kata

First try to run it.

Then your goal is to make it testable so that you can make changes (FIXME inside) and perhaps refactor it a bit.

This code draws on a C# code kata authored by my distinguished colleague Nicolas M.; Thanks Nicolas for the good ideas in the kata!

Personal notes about this kata

This kata is very interesting to practice several refactor techniques.

At first, you won't be able to test it, so you should relay on secure refactor techniques as provided by your IDE.

Notes on PHP version

This PHP version tries to mimic the behavior of the original java.

To try the code, clone or download this repo.

Then, run composer:

    composer install

This will install PHPUnit. PSR4 autoload for the QuoteBot namespace and lib folder is loaded via classmap.

And then, execute the run.php script to see how this program works (to say something):

    php run.php

Or use the IDE facilities to run.

Important note: you must not touch the lib folder, given it is considered a vendor.

Notes on practicing this kata inside docker

Start containers. First time docker needs to download images, so it could take a while.

docker-compose up -d

You can jump into the container

docker exec -it quotebot bash

Run composer install inside de container or

docker exec -it quotebot composer install

Notes on configuring PHPStorm with the dockerized environment

First of all, start up docker containers.

docker-compose up

Configure PHP CLI

Go to PHP Storm > Preferences > Languages and Frameworks > PHP

Clic CLI Interpreter …

Add Remote Interpreter from Docker

Select (radio button) docker-compose and select php service.

Configure XDebug

Go to PHP Storm > Preferences > Languages and Frameworks > PHP > Debug

Make sure XDebug port is 9001

Configure PhpUnit

Go to PHP Storm > Preferences > Languages and Frameworks > PHP > Test Frameworks

Add PhpUnit by remote interpreter configuration. Select the remote Interpreter you've configured before.

PHPUnit Library from composer autoloader. Path to script should be: vendor/autoload.php

Select phpunit.xml as default configuration file.

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If you hesitate where to start, here are some of the tricky bits that make it hard to test:

• Lack of dependency injection:
• A static main with no args
• Static service
• Hard-coded instantiation of a service that itself instantiates its dependencies, and again

Implementation issues:

• Very slow service
• Hidden dependency to a license key in env variable
• Random return value -> non-deterministic test
• Dialog poping up prompting for user input

Other tricks:

• New Date() in the middle of calculations -> non-deterministic test
• High combinatorial of calculations lead to too many required test cases
• Stateful behavior from internal cache: first call different from next calls
• Heavy dependency called within a large loop with different values
• Use a dependency or another depending on the passed parameter