Quick Guide To Test Driven Development and Testing Challenges

Test Driven Development

Testing software before launching it in the market has become more than just a trend; it’s become the need of the time owing to the cyber threats present on the Internet.

While the software development market keeps establishing tips for better software development, the software testing industry has now begun giving out information as well.

When it comes to software testing, test cases are more than just a step on the journey; they are the backbone of the whole testing process.

What is Test-Driven Development?

Let’s discuss one of the most famous techniques used for test case development: test-driven development (TDD). TDD is also called test-driven design and is widely used by every mobile application testing company. TDD is a method of software development in which source code is tested over and over again (this is called unit testing).

The philosophy that drives TDD is an emphasis on the present moment, which advances the notion of ‘building software that is working for now and can be modified later according to the needs’.

Testing is then performed and code is refactored after each testing cycle. This process of refactoring is repeated until all parts of the product are working according to the desired specification.

TDD is a part of Extreme Programming (XP), which is a straightforward approach to software delivery that comprises four basic activities: coding, testing, listening, and designing. 

A lot of companies like to build software in lesser time with the same efficiency and good results; we’re sure that anyone reading this right now feels the same way. Test driven development is used to build software typically in less time than by using other and older ways. Both developers and testers anticipate and are aware of how the software would work in the real world. TDD makes sure that all units are, at the very least, tested for optimal functionality. 

However, where test-driven development has a lot of benefits to offer to the industry, it has some drawbacks as well. One obvious limitation of TDD is tester can sometimes apply tests incorrectly, and this may result in software units malfunction in the real world. Users may encounter scenarios which are not implemented by the developer, nor tested by the tester. This usually results in the user sending the software back for edits, which, to be honest, is not great for the company’s reputation.

The Test-Driven Development Cycle

Now that you’re familiar with TDD, let’s talk about its life cycle. It will help you see how you can use it in the future if needed. Here are the basic steps that every company follows when using TDD:

1. Adding a Test

The very beginning of a feature is writing a test that can define the functionality, or improvements in functionality, which should be very clear and expressive. The programmer fully understands the specifications of features and requirements, so that they can be completed through use cases or user stories to cover the scope.

2. New Test Results

Tests are written for expected fail and success cases. This ensures that new tests don’t get passed without requiring new code changes. In fact, new tests should fail because no new code is written for those tests to pass — this also boosts a developer’s confidence when they see their tests getting failed or passed against expected conditions.

3. Coding

Here, the developer writes some code for a test to pass, but this code can always be improved in the desired way later. The developer has to take caution to not code the functionality that won’t be tested in the current test run.

4. Test Runs

Tests are conducted at this stage. If they pass, everyone is sure that newly written code meets the requirements and no old functionality was harmed. New code can always be adjusted if tests don’t work.

5. Code Refactoring

Programmers write a part of code to pass a specific test. Sometimes code is duplicated or written at a place that is more convenient to pass that test. Generally, a good practice is to clean the code on a regular basis and move the newly written code to its appropriate place after testing. Take care that there isn’t any duplication in the code.

With the addition of new features, code gets lengthy. To increase the readability, understanding, and maintainability; code is modified that way. Variables, objects, and methods are renamed properly. Programmers may rearrange the structure to a more logical form. Against each refactoring, tests are rerun so that the developer has more confidence about existing functionality.

6. Redo

To start a new test, the whole cycle is repeated to enhance functionality. If newly written code doesn’t pass the new test, or makes previously passed tests fail, the better course of action is for the developer to undo the changes. Instead of making tiny increments in external library code, it’s better to create a custom library to test software.

Testing Challenges

In addition to the limitations of TDD, there are a few more challenges:

  1. There are hundreds of traditional test cases which are incompatible with TDD, meaning that these test cases need to be prioritized and evaluated to separate important ones from the waste.
  2. Writing test cases for a feature again and again in the later stages, since detail oriented test cases can’t be written because of TDD’s limitations.
  3. Before you write test cases for a project in TDD, you should have the know-how and background in development and QA domains.
  4. Updating existing test cases for a feature repeatedly in later stages, because of continuous change.

Test-driven development allows developers to build the software in small steps, and to focus on the current task and make the test case pass. Developers then run unit tests to test the developed feature for positive and negative tests to get their expected results. TDD is a popular approach because of its flexibility, rapid change, and testable units. However, there’s more code to write in TDD than without TDD because of the unit test code. TDD is a testing technique to lower the defect density.