Test Driven Development(a short introduction)

(C) John Chandler 2011

Perfect Code?

First Time?

Every Time?

(yeah right)

Confidence Through Tests

Manual Tests = Error Prone

Automated Tests = Repeatable

Writing Tests After the Code

Is Useful

Writing Tests Before the Code

Helps us...

Think about What

before we decide How

Write code that is

easy to test

Write small units

of code at a time

Ensure all code

has test coverage

Know when to

stop writing code

First we write a test that fails

Then we write code

to make the test pass

Did we break anything?

Are we more confident?

Refactor if necessary

Refactor with confidence

Then repeat until done

What else?

Fail Fast

Early Feedback

Easier to learn

unfamiliar code

Easier to change

unfamiliar code

Supplementary

code documentation

Give confidence

to Others

Continuous Integration

Now go write tests!