TDD – Test Driven Development

Hendrik Neumann

Agenda

(1) Unit Testing

(2) ABAP Unit

(3) Test Driven Development

Unit Testing

Unit Testing

Definition

Unit Testing

Unit Testing is a method by which

individual units of source code are

tested to determine if they are fit to

use.

Unit Testing

Unit Testing is a method by which

individual units are e.g.ource code

fittMethods of t Function Modules fit

Function Groups

fiMoModule Pools Function

Functn Reports

Methods

Function Groups

Unit Testing

aim:

Find bugs early

Write once, run often

Effective Tests must be automated

solution:

xUnit Frameworks

xUnit Framework

xUnit Framework

Definition

xUnit Framework

Provides an automated solution with no need to write the same tests many times and no need to remember what should be

the result of each test.

xUnit Framework

How does it work?

xUnit Framework

setup()

creates object under test – used in all tests

xUnit Framework

setup() test_method()

Clear up your mess..

calls object under test – e.g. a public method

with test data

xUnit Framework

setup() test_method()

assert_*()–methods

verify the return value of the object under test using

xUnit’s assert methods

xUnit Framework

setup() test_method() teardown()

Clear up your mess..

xUnit Framework

setup() test_method() teardown() test_method()

test_method() test_method()

test_method() test_method()

test_method()

ABAP Unit

ABAP Unit

SAP‘s xUnit implemenation

ABAP Unit

cl_abap_unit_assert=>assert_equals(

msg = 'Test msg'

act = act

exp = out->( )

).

assert_*()-Methods

ABAP Unit in ADT

ABAP Unit

Local test classes for global development artifacts

In Reports, Function Modules and Classes

Not acitve on production systems

ABAP Unit

• Tools integration:

–ABAP Workbench

–Code Inspector Integration

–ABAP Unit Browser

–ABAP Test Cockpit (ATC)

–ABAP in Eclipse

Test Driven Development

Test Driven Development

• Never

• After you wrote your code

• Before you write your code

When do you write your Unit Tests?

Test Driven Development

• Never

• After you wrote your code

• Before you write your code

When do you write your Unit Tests?

Test Driven Development

Test Driven Development

Test 1st

Test Cycle

Test Write a test that expresses how you’ll use

the code and what you need it to do.

Test Cycle

Write enough code to get the test to pass, but no

more.

Code

Test

Test Cycle

Code

Test

Refactor Clean up the code to remove redundancy and improve the design.

Test Cycle

Code

Test

Refactor

Test Cycle

Code Test

Refactor

Test Cycle

Code

Test Refactor

Test Cycle

Code

Test

Refactor

Green Bar Patterns

Green Bar Patterns

Fake it till you make it

• Start with hardcoded results and wait until tests force them to become real

Green Bar Patterns

Triangulate To Abstraction

• Make the code abstract only when you have two or more examples

Green Bar Patterns

Obvious Implementation

• aka Don‘t be stupid

• If you really know the right way to implement it, do it that way

Have FUN!

Backup

Code Kata: Roman Numerals

Rules: • smaller number in front of a larger number subtraction • all else addition • put only one smaller number in front of a larger number • ones, tens, hundreds and thousands are separate items

I The numeral one. II is two, III is three.

V The numeral 5. IV is 4, VI is 6, VII is 7, VIII is 8.

X The numeral 10. IX is 9, XI is 11, etc.

L The numeral 50. XL would be 40.

C The numeral 100. C is short for the Latin word Centum, but Century is eaysier to remember ;-)

D The numeral 500.

M The numeral 1000.