Functional Testing Approaches and Agile Considerations
Functionality testing is the examination of a coded system’s response to expected usage. Notice that doesn’t talk about cosmetic appearance, performance, security or compliance of any sort.
What is Functionality Testing?
Functional testing is a process of verifying that a system performs as expected when its features are exercised by another system or directly by a user. This means that it lends itself nicely to test case and usage case definitions that can provide a stable, repeatable basis for evaluating the progress of system development.
The entire range of the development process comes under the purview of functionality verification.
- Unit tests should start at the very beginning to ensure that each block of code performs its intended manipulation of inputs into desired outputs for the next module.
- Integration tests assure that the unit modules connect to each other as expected and convey data and commands throughout the system per the specifications to which it was built.
- Sanity checks verify that modifications and fixes applied to the code body don’t have unexpected side effects in, apparently, unrelated parts of the system.
- Regression tests verify that later feature additions and bug fixes don’t undo previous efforts or interact with them to cause wholly new problems.
- Usability acceptance is the actual operation of the system in the context in which it was designed to be used and is the gateway to deployment.
All of the above are varieties of functional testing and they all contribute to the creation of a software system that is ready to deploy for its intended use.
Functional Testing Approaches
Three approaches are commonly used to implement functional testing.
1. Black Box Testing
Black box testing takes an array of inputs and looks for the generation of specified outputs. The idea behind the name is that the contents of the code under test is unknown to the test case and, by definition, to the tester who is only concerned with function verification.
2. White Box Testing
White box tests are at the other end of the spectrum. They are predicated on knowing exactly what is going on with the code under test and tests are executed primarily to verify the robustness of the code rather than its absolute functionality.
White box testing is performed at the beginning of the development process with unit tests and into the early parts of the integration phase. Black box test work is typical of the latter phases where response to specific operating scenarios is important.
3. Gray Box Testing
The third type of testing is a mixture of black and white box. This happens as development moves into a crossover zone towards the end of integration and the beginning of usability.
Obviously, black box testing lends itself to closely defined test cases and rigorously defined test results. These are tests that can be performed by test techs who are capable of carefully following test plan instructions and meticulously documenting results.
White box testing is best performed by software engineers who understand how the code is written and the permutations of how it is expected to perform.
Functional Testing in an Agile Environment
The move from the waterfall SDLC to Agile development and from there to Continuous Integration and on to Dev/Ops has pushed hard on the software quality paradigm. With the move to Agile in particular, test time became viewed as a luxury and, therefore, as being somewhat dispensable. The push back on this has been brutal.
Apps released without sufficient testing were savaged by customer reviews on an Internet that makes bad news travel like a supersonic aircraft. A logical outgrowth of this situation has been the drive towards test automation and it makes a lot of sense in today’s high velocity development environments. Unfortunately, this has led to an unfounded expectation that all testing should be automated and that it will cure all development ills.
Automating Functional Testing
Test automation works best where there is a test that is well defined and must be performed many times or requires a very complex advanced system setup. Tests that vary from release to release, require human cognition (think intuitive user interface validation) or need ad hoc variation as in exploratory testing are poor candidates for automation. Test scripts written for unsuitable tests will incur script maintenance costs that will result in their ultimate abandonment because of failures due to test design errors.
Functional Test Documentation
Test documentation is golden. As much as the press for quick development and short release intervals pushes quality to take shortcuts, documentation is too valuable to disregard. Test automation, where appropriate, will help document test processes as will careful completion of defect reports that document regression tests.
And recognize that a mix of talent is needed across the span of software development. Agile demands the integration of quality and development with product management. Use this motivation to make teams ever more granular and seed them with test engineers. Putting quality and development in adjacent seats cross-pollinates the two disciplines to the benefit of both.
Understanding Agile Testing: Key Methods to Know
In agile software development, adopting effective testing techniques is crucial for improving the quality of testing practices and facilitating automated testing. The following are three pivotal methods that are commonly utilized:
Test Driven Development (TDD)
TDD is a foundational agile testing method that emphasizes writing tests before code. Developers begin by crafting a test for a specific functionality, only then writing the minimal amount of code necessary to pass the test. This cycle—test, code, refactor—ensures that each piece of code is thoroughly validated, leading to cleaner, more reliable software.
Acceptance Test Driven Development (ATDD)
ATDD bridges the gap between developers, testers, and business stakeholders by focusing on writing acceptance tests before development begins. These tests, derived from user stories, define the criteria for success from the end-user’s perspective. By ensuring everyone is aligned on the desired outcome, ATDD helps deliver features that truly meet user needs.
Behavior Driven Development (BDD)
Building on the principles of TDD, BDD adds an additional layer of clarity by using natural language to describe tests. With BDD, tests are written in a format that is understandable by all team members, often utilizing frameworks like Cucumber or JBehave. By making the behavior of software explicit, BDD promotes better communication and collaboration across a development team, ensuring that the software behaves as intended.
These agile testing strategies not only enhance code quality but also foster collaboration and clarity throughout the development process. By integrating TDD, ATDD, and BDD into your workflow, you can significantly boost efficiency and ensure that what you build aligns with user expectations.
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Frequently Asked Questions About Functional Testing and Agile Considerations
What is the Main Focus of Behavior Driven Development (BDD)?
Behavior Driven Development (BDD) centers around a single key question: Are the features and data performing as intended? It emphasizes ensuring that software meets specified requirements and expectations.
Key Objectives of BDD:
- Collaboration Across Teams: BDD fosters effective communication among developers, testers, and non-technical stakeholders. This collaboration helps in creating a shared understanding of desired outcomes.
- Executable Specifications: It utilizes scenarios written in a simple format, often using tools like Cucumber or SpecFlow, making sure specifications are understandable to everyone involved.
- Focus on User Experience: BDD encourages thinking from the end-user’s perspective, ensuring that the design and functionality align with user needs and behaviors.
By focusing on these elements, BDD ensures that development is aligned with both business goals and user expectations, minimizing misunderstandings and enhancing the overall quality of the product.
What is the Main Focus of Acceptance Test Driven Development (ATDD)?
Acceptance Test Driven Development (ATDD) focuses on ensuring that a software solution meets its intended requirements. The primary goal is to verify that the developed system satisfies the needs and expectations set out by the stakeholders.
In other words, ATDD aims to confirm that the final product does precisely what it is supposed to do. This is achieved through collaboration among developers, testers, and business representatives who work together to define acceptance criteria. These criteria guide the development process, ensuring that each feature is implemented correctly and aligns with the agreed-upon requirements.
By focusing on these outcomes, ATDD helps create more reliable software that delivers value to its users.
What is the Main Focus of Test Driven Development (TDD)?
The primary focus of Test Driven Development (TDD) is to ensure that the code fulfills its intended purpose. This approach emphasizes writing tests before the actual code, guiding developers to create software that consistently meets requirements. By doing so, TDD helps in identifying the necessary functionalities and ensures that the implementation aligns with the expected outcomes right from the start. The result is a more reliable and maintainable codebase, where each feature is meticulously validated through predefined tests.
Author: Gary James
