Part 2: Catching Bugs Early
Tags: testing, beginners, programming, writing
Published: 2023-01-13 21:09:59

One of the main benefits of unit testing is that it allows developers to catch bugs early in the development process. By testing individual units or components of the software application, developers can identify and fix issues before they make their way into the final product. This can save a lot of time and resources compared to catching and fixing bugs later on in the development cycle or after the product has been released.

It’s important to write tests for edge cases as well as the most common scenarios. Edge cases are the less likely scenarios, but they are also the ones that can cause the most problems. By testing for edge cases, developers can identify and fix issues that would otherwise go unnoticed. For example, in a function that takes two integers as input and returns their sum, an edge case would be when one or both of the input integers are the maximum or minimum value that an integer can hold.

It’s also important to write tests for all the important functionalities of the software. This way, it ensures that all the features are working as intended. Writing test for the core functionality of the software is crucial, as it can help prevent regressions and ensure that the software performs as expected.

Unit testing also provides a way to ensure that new changes don’t break existing functionality. Every time a change is made, the unit tests are run to check if the code still works as expected. If a test fails, it means that something is wrong and needs to be fixed. This helps to catch and fix issues early on, before they cause more serious problems down the line.

---
Example Use Case:

Consider a software application that manages financial transactions for a bank. As part of the development process, the team writes unit tests for the code that handles the processing of transactions. These tests cover different scenarios, such as the deposit of funds, the withdrawal of funds, and the transfer of funds between accounts.

During development, the team runs these tests frequently to ensure that the code is working as intended. One day, a developer makes a change to the code that handles the withdrawal of funds. They run the unit tests, and one of the tests fails. The test is designed to check that the withdrawal of funds is processed correctly, and it fails because the change that the developer made introduced a bug.

Thanks to the unit tests, the bug is caught early in the development process, and it can be fixed quickly. If the bug had not been caught, it could have gone unnoticed and caused issues in the production environment, resulting in incorrect transactions and unhappy customers.

---

In summary, unit testing helps to catch bugs early in the development process by testing individual units or components of the software application. Writing tests for edge cases and important functionalities can also help to identify and prevent bugs. Additionally, unit testing provides a way to ensure that new changes don’t break existing functionality, by running the tests every time a change is made. This helps to catch and fix issues early on, before they cause more serious problems down the line.

Series: Why unit testing is important ? All about unit testing

[Part 1: Introduction to Unit Testing](https://dev.to/svenherr/part-1-introduction-to-unit-testing-with-examples-21k2)

[Part 2: Catching Bugs Early](https://dev.to/svenherr/part-2-catching-bugs-early-b3f)

[Part 3: Ensuring Code Quality](https://dev.to/svenherr/part-3-ensuring-code-quality-with-examples-3p3n)

[Part 4: Living Documentation](https://dev.to/svenherr/part-4-living-documentation-with-examples-chk)

[Part 5: Continuous Integration and Deployment](https://dev.to/svenherr/part-5-continuous-integration-and-deployment-with-examples-2hkg)