Acceptance test driven development

Journal of Advanced Computing and Communication Technologies (ISSN: 2347 - 2804)
Volume No. 2 Issue No. 1, February 2014

Acceptance Test Driven Development
By

Vishal Aggarwal, Manpreet Singh
Infosys Limited, Chandigarh, India – 161001
Infosys Limited, Chandigarh, India – 161001
vishalaggarwal27@gmail.com, ksinghmanpreet@gmail.com
ABSTRACT:

development during walkthrough of the developed code, before

This document addresses the benefit of acceptance test

taking it on to live.

driven development processes and solutions in the IT
domain. Over a past decade it seems that the business
requirements are fluidic in nature. In order to ensure
quality IT deliverable with minimal rework and lower defect

In midst of these dynamics there is a need of sustainable
framework to minimize the impact of changing requirements
and thus the wastage of the efforts laid to build up the codebase.

density, in midst of the ever changing business requirement,

Automated test suites that can be integrated with continuous

it’s important to ensure following:

integration servers in this direction becomes the need of an hour.



Requirement understanding at granular level since
the day of inception.



Tangible,

measurable

and

testable

code

2. TEST DRIVEN DEVELOPMENT
Test Driven Development (TDD) although is a proven

development meeting user’s requirements.

approach to build automation regression suite around each

Regular feedback based interim automated testing

function and method. This definitely helps in validating the

during the course of development cycle.



output of each function and make sure function adheres to
the developed specifications.

Keywords:
Agile, Acceptance Criteria, Business Requirement, Acceptance
Test Driven Development.

But as per the 2010 report [1] the success percentage is around 60
only. This might stem up due to incorrect requirement gathering
of communication gap between the business owner and the

1. INTRODUCTION

component team.

One of the major challenges witnessed by product and solution

Hence, there is a need to build an automated suite of functional

delivering organization are the changing requirements from

test cases that can validate the acceptance criteria’s set by

business owners.

business analysts or applications owners.

The timing of the change can be anytime during the course of

3. ACCEPTANCE TEST

the deliverable like even during the mid-phase of development
cycle. Gaps and Defect density tend to increase under such
scenarios due to demand been in upswing and aggressive time
lines to be met.

Acceptance tests usually represent the functional end to end
tests keeping product or an application in scope
Acceptance tests are driven by the end user requirement of the
system or application. These are then reviewed by a designated

Agile unlike the waterfall model is one of the most promising

business analysts, process consultant, and end to end designers.

way of executing the projects while supporting the dynamics of

This helps in estimating the usage of the user requirement from

getting the regular feedback from the users on the partial

strategic view point and defining the granular level requirement
of the system or application to be developed. Doing so also

helps to improvise and refine the user requirement. This activity

acceptance (or functional) test cases for a solution or a product

in turn helps in estimating the appropriate size of an application.

and thereafter use the acceptance test cases for further
development.

4. HOW ACCEPTANCE TESTS ARE

5.1

DIFFERENT FROM UNIT TESTS

Functional / Acceptance Testing

The primary aim of any testing (unit, acceptance or functional)
Unit Tests are used to test the latest functionality developed or

is to identify and resolve defects at the earliest in the SDLC.

updated like a method or a function for a given class or an
object. The unit tests focus on the lowest possible functionality

IVVT or end to end functional test teams perform functional

and focus on the technical aspects. Normally, the scope of unit

testing of an application post the development sprint. This

tests is aligned to the particular function and scenario under

approach ensures the quality deliverable of an application being

development. Database aspects of the incoming/outgoing calls

rolled onto a production stack. However this comes with certain

are the key aspects of these unit tests

limitations:

Acceptance Tests are oriented to capture the acceptance
criteria’s for the end to end journey of the product(s) or



Any

functional

gaps

identified

outside

the

development sprint makes it difficult for developers to

service(s) being offered/rolled out.

fix the issue, as there might be cascading impacts on
the other deliverables

Mock
the
interfac
e

Function under unit
test
Dependency
injection to
mock the
composite
interfaces

Fixing issue at later stages results in costly re-work in
terms of
o

Impact analysis

o

Development

o

Mock the
call to
another
function

Re-testing to validate the fix(s)

This may result in delayed deliveries or unmanageable
developed code because of hacks being added to fix
the defects

In comparison to unit test cases, acceptance tests are dependent



on user requirement to ease the way of the working. This also

Extra time and effort required to run the regression
pack for any major or minor changes in an application

helps to reduce the cycle time of the overall process

It includes the interactions between different modules of the
applications, systems, database, user interface, and manual
touch points to name a few.

It’s advisable to have the appropriate data live like data set up
rather than dummy to for execution to provide near to realistic
results.

5. ACCEPTANCE TEST DRIVEN
DEVELOPMENT
Acceptance

Tests

Driven

Development

(ATDD)

is

a

collaborative exercise between consultants, designers (to build
the acceptance criteria’s), testers and developers to first write

5.2

How ATDD helps

Acceptance test driven development takes an approach to first
define and automate the acceptance tests for the piece of work
under consideration. Rather than verifying the developed work
at end of development cycle, ATDD ensures continuous
feedback to the developer on functional gaps resulting in defect
free code at end of development cycle.


Ensures all developers understand the requirements at
granular level



Early feedback to the developers with failed tests
during the development cycle



Since issues are identified during development sprint,
the fixes can be arranged quickly in a strategic way



Complete

automated

regression

suite

helps in

validating the quality of an application during any
further enhancements

Fail the Acceptance Tests:
It’s expected that for the above mentioned new acceptance test
cases must fail if the functionality is not developed. To ascertain

6. ATDD MODEL

these acceptance test are run on the existing code.

With ATDD, developers are supposed to write functional or

Thus idea behind failing these tests first is to ensure the

acceptance tests first, thereafter will proceed with writing of unit

completeness of end objective once code is developed and test is

test cases that are more atomic with the objective of expecting

passed. In case test case(s) is/are passed without developing the

the defined output from each function or method and finally the

code, it essentially means no need of any development.

actual working code.

Write the Unit Tests: After defining the end objective in

Write the Acceptance Test: as a first step, development

form of functional (acceptance) test cases, it’s important for

team write the acceptance test(s) for the given use case(s) before

developers to write the unit tests before the functional code.

the actual functionality is developed.

This helps to ensure that every line of code is testable and has
the defined purpose, hence ensuring the best practices. This also

This ensures:

helps in eliminating any unwanted lines of code.

•

development satisfies the testability criteria

•

all the expectations of customers are considered and

While writing unit tests, developers should ensure that unit is

met as per the standards

smallest entity to be tested for given functionality.

Fail the Unit Tests: Since the functional code is yet not
ready, the above unit test must fail. This to ensure that after
writing the functional code, the objective of that particular
function is met.

Write the functional code: Implement the objective of
functional unit and ensure the unit test pass.

Refactor the code (if required) to optimize it further while
ensuring no unit test case fails.

The Unit cycle (TDD) is repetitive till the end objective of
passing the acceptance test is achieved.
Finally integrate the build activities and test execution with
continuous integration server

[2][3][4]

to ensure that test cases

(both acceptance and unit) got executed with every build.

7. ATDD TOOLS
•

Concordion[5]

Concordion is a java based framework on top of junit runner
that helps writing the acceptance criteria’s on to HTML page in
an assertion mode. This helps in displaying the final results on
HTML page with useful documentation highlighting the pass
and failures using color code.
The tests can be written in pure business language on HTML
page, which is thereafter picked by java classes for analysis and
execution of test criteria in HTML’s.
Concordion helps evaluating the results on web pages by using
web drivers (Selenium).
•

FitNesse[6]

FitNesse is also web page testing framework on top of junit that
can receive instructions both from well-defined acceptance
criteria’s written on top of HTML and wiki text as well.

8. CONCLUSION
With ATDD we found that teams have better understanding of
the requirements as it mandates the exact behavior in terms of
acceptance

criteria’s.

The

improved

understanding

of

requirements results in reduced defect density hence reduced
CoQ (Cost of Quality). This also helps in simplifying the need
of continual or breakthrough improvement as per changing
business requirement. Thus, we consider that ATDD is an
effective way of developing an application in the continuous
evolving environment.

9. REFERENCES:
[1]: http://www.drdobbs.com/architecture-and-design/2010-itproject-success-rates/226500046
[2]: http://jenkins-ci.org/
[3]: http://hudson-ci.org/

[4]: http://www.jetbrains.com/teamcity/
[5]: http://www.concordion.org/
[6]: http://fitnesse.org/

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