Workshop on Test Driven Development (TDD) Noida

© 2013 iZenBridge | CONFIDENTIAL

Introduction

to

Test Driven

Development

(TDD)


Introductions!

1.Your Name

2.Current company & Role

3.Experience with Agile and TDD


Agile Software Development


Traditional Design – Code – Test

Design Code Test

Test Code Design /

Refactor


Why Not Testing at the End?

• Hard to improve quality of

existing code – Complacency and Recency

• Feedback opportunity is

lost

• The future state of the

project is difficult to gauge

• Testing is more likely to be

cut


Stress and Testing

Project

Stress

Less

Testing

Just get it done, will ya?


Test Automation Pyramid

UI

Service

Unit

UI

Service

Unit

Agile Traditional


Test First Development

ATDD and TDD


ATDD vs TDD

Source: Test Driven: Practical TDD and Acceptance TDD for Java Developers


Why TDD?

The Benefits of TDD:

• Limits WIP – a key Lean principle

• Ensures testing at lower granularity level – the smallest

testable unit of code

• Ensures no untested code goes to production

• Helps high degree of conformity between code and the

real business requirements

• Helps keep unused code out of the system (unwritten)

• Makes codebase more maintainable – via regression

testing


The TDD Cycle

Red

Green

Clean

Test

Code

Refactor


Three Laws/ Rules of TDD

You will not write any production

code until you have written a failing

unit test.

First Law


Three laws of TDD

You will not write more of a unit

test than is sufficient to fail, and

not compiling is failing

Second Law


Three laws of TDD

You will not write more production

code that is sufficient to pass the

currently failing test.

Third Law


Misconceptions About TDD

• Writing code first, then tests is

same as TDD

• TDD isn’t useful for designing

architecture

• Takes too much time

• Too complex to learn and

implement

• TDD is only good for small

projects



Let’s Build Something Now!


String Calculator – TDD Exercise

Define Scope:

• Supported operators?

• Acceptable characters?

• Whitespace?

• Max length of expression – number of operations?

• Max length of each number?

• Fractions?

• Parenthesis?


String Calculator (continued)

Time to start Failing!

• Reminders: • Test, Code, Refactor – REPEAT until Done!

• Add feature layers one by one, in small manageable increments

• Setup • Eclipse for Java Development

• JDK

• Team formation



1. Two literal addition

A + B



2. Multiple literal addition

A + B + C

A + B + C + D



3. Combination of addition and subtraction

A + B – C

or

A – B + C



4. Simple multiplication

A * B

A * B * C



5. Simple division

A / B

A / B / C



6. Combination of multiplication

and division

A * B / C

A / B * C

Does order matter?



7. Combination of all four

A + B – C * D / E

Order does matter here!



8. Invalid expressions

• Banned chars - alpha, parenthesis, special chars

• Space between a number

• Two operators clubbed together

• First number negative

• Invalid decimal number


What Next?

Certified Scrum Developer (CSD)

A 3-day course certified by Scrum Alliance that focuses on

specialized Agile engineering skills:

Test Driven Development (TDD)

ATDD, BDD – Selenium/ Cucumber

Continuous Integration – Jenkins

Agile Design and Architecture

Refactoring

Collaboration


References

Test Driven Development: By Example - Kent Beck

Succeeding with Agile - Mike Cohn

Test Driven: Practical TDD and Acceptance TDD for Java

Developers - Lasse Koskela


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Education

Workshop on Test Driven Development (TDD) Noida