Understanding Test Driven Development (TDD) for Effective Testing
Written on
Chapter 1: Introduction to TDD
Testing is a crucial aspect of deploying any website or web application, and it can be conducted through various methods. Each organization or individual may adopt different testing methodologies. One popular approach that frequently arises is Test Driven Development (TDD). This article will explore what TDD entails, how to implement it, and why it serves as an effective means of identifying errors before they reach production.
Section 1.1: What is TDD?
Test Driven Development (TDD) involves creating an automated test script to confirm that code functions correctly before the actual code is written. At first glance, it may seem odd to write tests for code that doesn't yet exist, but there’s a solid rationale behind this practice.
The core idea is to establish success criteria for a piece of implementation code at the outset. For example, if you're developing a script to take user input and format it to title case without whitespace, you would first define the objectives. A test script is then created to ensure these goals are met.
Initially, when this test script is executed, it will fail because the implementation code has not been developed. However, the coding process can begin, and the test script can be run at various stages until it successfully passes all tests. Should the implementation criteria change, the test script can be adjusted accordingly.
The video titled "What is TDD? What is Test Driven Development?" provides an overview of TDD and its principles.
Section 1.2: Example of the TDD Loop
To clarify the TDD process, consider a scenario where a client requests a feature to convert Kelvin temperatures to degrees Celsius.
In TDD, the first step is to establish success criteria and write a test script accordingly. For instance:
- The input number must be positive (as temperatures below absolute zero are not feasible); otherwise, an error is returned.
- If the input is 300K, the output should be 26.85°C.
Once the test script is prepared, link it to your blank implementation code and run the tests. The tests should fail initially, indicating that the conversion logic has yet to be implemented. If the tests pass at this stage, it suggests there’s an issue with the test script that needs addressing.
As you develop the implementation code, continually refer to the test script to monitor progress. Once the test script passes, the objectives have been achieved. If the client later requests the addition of Fahrenheit conversions, it's essential to pause and define tests for this new requirement before proceeding with any coding.
Chapter 2: Advantages of TDD
The second video titled "Introduction to Test-Driven Development (TDD) with TypeScript | 2021" offers insights into implementing TDD with TypeScript.
The primary benefits of employing TDD include:
- Ensuring that tests do not always yield a positive outcome, as the initial run is purposely intended to fail.
- Keeping development focused on achieving project objectives, since only implementation code that addresses failing tests is written.
- Maintaining a design cycle that aligns with project goals, allowing for any changes to be properly scoped with defined success criteria before coding.
- Facilitating early error detection, as it's quick and straightforward to execute the pre-defined test code from the project’s inception.
In conclusion, Test Driven Development is an effective strategy for achieving a results-oriented testing methodology. While it may seem counterintuitive to create a test script prior to writing the main program, this approach offers numerous advantages. Developing tests necessitates a clear understanding of the intended outcomes for the function or script, which aids in the overall design process. Furthermore, having the test script in place early on allows for the identification of bugs sooner, minimizing rework costs.
Thank you for taking the time to read this guide!