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Showing posts with label Acceptance test driven development. Show all posts
Showing posts with label Acceptance test driven development. Show all posts

Sunday, September 7, 2014

What is the difference between Test Driven development and Acceptance Test Driven development?

Test driven development (TDD) and Acceptance Test Driven Development (ATDD) are related to each other. TDD is a developer’s best tool for helping in creating properly written code units i.e., modules, classes and functions, that carry out the desired function properly. On the other side, ATDD acts as a tool for communication between the developers, testers and the customers to define requirements. Another difference between TDD and ATDD is that the former requires test automation while ATDD does not. But ATDD might require automated regression testing. The tests written for ATDD can be used for deriving tests for TDD. This is so because a part of the requirement is implemented in the code. It is important that the tests must be readable by the customers, but it is not required for TDD tests.
TDD involves writing the test cases and making them fail before the code is written. Next enough code is written to make the tests pass and then refactor it as per the requirements. The tests must pass after it. The primary focus of TDD is on methods and single classes i.e., the low level functionality. This leads to much flexible code. Now what is the need for ATDD? The reason is that the TDD just tells you that your code is fine but it doesn’t tell you why that piece of code is even required. However, in ATDD, in the early stages of the software development process itself the acceptance criteria are stated. In the succeeding stages of development process this criteria is used for guiding the development. ATDD is more like a collaborative activity engaging everyone from developers and testers to business analysts and product owners. It ensures the implementation process is understood by everyone involved in the development process.
There is a third thing called the BDD or the behaviour driven development. This one is quite similar to TDD except that we call tests as specs. The focus of the BDD is on system’s behaviour rather than its implementation details. It also focuses on the interactions taking place in software development. Developers following this approach make use of two languages i.e., the domain language and their native language. TDD consists of unit tests while ATDD uses acceptance tests. Plus, the focus is on high level. BDD is required for making the product more focussed on customer. BDD allows the collaboration of developers with other stakeholders easy. Using TDD techniques and tools requires technical skills because you have to know the details of the object. Non – technical stakeholders would be lost while following the unit tests of TDD. BDD provides a clearer view of the purpose of the system. TDD provides this view to the developers.
The result of the methodology of ATDD is entirely based up on the communication that takes place between the developers, testers and their customers. A number of practices are involved in ATDD such as Behavior driven testing, specification by example, story test – driven development, example – driven development and so on. With these processes, the developers are able to understand the needs of the customers before the actual implementation. The difference between TDD and ATDD arises because of the latter’s emphasis on the collaboration between the three i.e., developers, testers and customers. The acceptance testing is encompassed in ATDD but in one way it is similar to TDD i.e., it insists on writing the tests before coding can be started. These tests provide an external view of the system from the point of view of a user.


Tuesday, May 8, 2012

What is meant by the acceptance test driven development?


Test driven development is nowadays quite popular among the programmers and developers and is gaining new heights. More and more software programmers and developers are now approving of the test driven development.  
Test driven development now seems to be making its mark after it is being considered as an individual software development process rather than being related to the first programming concepts of the agile software development methodology called the “extreme programming or XP”. 
Many different types of the test driven development have been identified such as the acceptance test driven development, traditional unit test driven development etc.

This piece of writing has entirely been dedicated to the acceptance test driven development methodology. But before we move on to the acceptance test driven development, we should be familiar with the usual test driven development process so that we get a better understanding of the acceptance test driven development. 

Steps in Test Driven Development


Test driven development is a development methodology unlike others which involves the creation of tests before the actual production of the code for the functionalities. The development cycles are shorter than the normal or usual software development cycles and consist of the following steps:

  1. Addition of tests for new features that should fail.
  2. Writing of code which enables the tests to pass.
  3. Finally the refactoring of the code.

Styles in test Driven Development


Above 3 steps constitute a shorter development cycle that is repeated several times till the code is considered to be perfect and complete in all aspects. Several approaches or development styles have been developed like:

  1. YAGNI (you ain’t gonna need it)
  2. KISS (keep it simple stupid)
  3. Fake it till you make it and so on.
All the development styles of the test driven development follow the two basic steps:

1. Writing of the automated unit tests before the actual features and functionalities are implemented in to the design of the software system or application.
2. Failing the above written tests: Every automated unit test is expected to fail because then only it is said to be working properly.

What is Acceptance Test Driven Development?


1. It is a development strategy that helps in building coordination in the software project so that the software product is delivered exactly as needed by the customer or the client and also in this the required functionalities are not implemented halfway. 
2. Acceptance test driven development methodology involves one or more than one customer tests for testing the customer centred features.
3. Here the requirements are treated as the executable tests.
4. We can say that the acceptance test driven development is way of bring the stake holders together on an early basis for the clarification of the requirements and thus bridging the gap between the requirements and the tests.
5. Acceptance test driven development involves the collaboration of whole development team in defining the acceptance criteria and finally turn them in to a set of distinct acceptance tests before the starting of the development process. 
6. It can be considered as a good means to know that what is being developed.
7. Acceptance test driven development is categorized under the category of agile software development process.
8. It involves the extension of the test first approach to front end of the software system or application under development process. 
9. The acceptances test like the other entire test driven development variants must fail.
10. Customers want a software product that increases productivity, helps in making more money, improving operation capability and so on. 
11. This is what is delivered with the help of the acceptance test driven development. 



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