How to write: Clean, Testable code
Psychology of Testing
(or why our intuition of testing is wrong)
-- Miško Hevery

http://goo.gl/V0aWx

Testing is not like frosting

Micro Development Model
Develop Check-In Test

automate

Development Model
Software Engineers

Develop

Design

Testing magic

QA

Manual Tests Exploratory Tests

Test Engineers

Automated Tests

Tools

Testing magic

Excuses
Valid Excuse Legacy code-base

Don’t know how
I write UI

“Dirties Design”

No Tests

Testing is for QA

It doesn’t catch bugs It’s slower It’s boring

Too many interfaces

Hard to change Common Misconception

How do you write HARD TO TEST code?

Less Theory more Hands-on

http://www.flickr.com/photos/doozzle/149885028/

Imaginary Interview
Your mission, should you chose to accept it, is to make this code testable ● I did not say understand what it does ● I did not say write a test http://bit.ly/92Ozrz public class InboxSyncer { private static final InboxSyncer instance = new InboxSyncer(Config.get()); public static getInstance() { return instance; } private final Certificate cert; private final String username; private final String password; private long lastSync = -1; private InboxSyncer(Config config) { this.cert = DESReader.read(config.get(“cert.path”)); User user = config.getUser(); this.username = user.getUsername(); this.password = user.getPassword(); } public sync() { long syncFrom = lastSync; if (syncFrom == -1) syncFrom = new Date().getTime() - Defaults.INBOX_SYNC_AMOUNT; Inbox inbox = Inbox.get(username); POPConnector pop = new POPConnector(cert, username, password); pop.connect(); try { Iterator messages = pop.messagesIterator(); Message message; while ( messages.hasNext() && (message = messages.next()).getTime() > syncFrom ) { if (Defaults.FILTER_SPAM ? MessageFilter.spam(message) :