/ Playwright Guide
In the world of software engineering, code quality is critical to ensuring that applications are robust, scalable, and error-free. A crucial way to ensure that software works as expected is through automated testing. These tests are an essential practice for improving quality and reducing the time it takes to find and fix bugs. In this article, we will explore what automated testing is, why it is important, and the main types of testing used in software development.
What are Automated Tests?
Automated tests are programmatic executions of a series of checks on an application, designed to ensure that the software behaves correctly. Unlike manual testing, where a tester performs a series of actions and verifies the results, automated tests are executed by scripts or tools that simulate various use cases and verify the results autonomously.
These tests are a key part of the Continuous Integration (CI) and Continuous Delivery (CD) process, where code is continuously verified and deployed into production. Automation allows you to run tests multiple times, with every change in code, ensuring that new features or fixes do not break existing ones.
Why are Automated Tests important?
There are several aspects that make it worth investing time in implementing automated tests. Here are the most relevant ones:
- Efficiency: Automating tests significantly reduces the time needed to perform repetitive checks, allowing developers to focus on more complex tasks. This benefit is especially noticeable when it is necessary to repeat tests after every change in the software in order to ensure non-regression (Non-Regression Test – NRT).
- Reliability and repeatability: Humans can make mistakes during manual testing, while automated tests always perform the same operations reliably. It also ensures that the test is repeated the same way every time.
- Long-term time savings: Although writing automated tests requires an initial investment, this quickly pays off in the form of fewer bugs and increased software stability.
- Rapid feedback: By integrating automated tests into the development process, developers can quickly receive feedback on code changes. This makes it possible to identify and fix problems before they become critical. A clear example is performance testing that helps identify issues in advance, which might otherwise arise in a production environment. These problems often occur under load conditions that are hard to replicate with manual testing, potentially blocking user operations.
However, in order to benefit from automated tests, they must be carefully designed by identifying the right types and test scenarios depending on the specific context of the software. It is therefore necessary to avoid implementing superfluous or insignificant tests, focusing instead on a few quality cases.
What are the main types of Automated Testing?
There are different types of automated tests, each of which has a specific role in ensuring the quality of the software.
Unit Tests
Unit tests are automated tests that verify the correct functioning of individual units of code, such as methods or functions, in isolation. These tests aim to evaluate a specific part of the code, ensuring that, given certain inputs, the expected results are obtained.
For example, if a function needs to add two numbers, a unit test would verify that, by inputting 2 and 3, the result is actually 5. Unit tests exclude any external dependencies such as databases, APIs or other parts of the system, allowing you to evaluate the behavior of a single piece of code.
Integration Tests
Integration tests verify how different units of code interact with each other. While unit tests check individual components, integration tests focus on the correct interaction between modules or services. The goal is to ensure that the various components work correctly when combined, preventing bugs due to poorly designed interfaces or inconsistencies in the data transmitted.
For example, in an e-commerce application, an integration test would verify that the cart module can actually communicate with the payment module, ensuring that the transaction is completed without errors.
Integration tests can be performed at different stages of the software lifecycle depending on the type of test:
- before deployment: if you need to verify the integration between different pieces of code within the same application component (e.g. classes that are correctly invoked by each other);
- after deployment: if you need to test the integration with other external application components (e.g. databases or other services).
When performing integration tests, it is usually good practice to mock interactions with external third-party resources. This allows you to reliably test the behavior of the system without risking introducing unpredictable variables related to external events. When this condition is met, we specifically talk about “local integration tests“. There are also cases where you are really interested in monitoring the correct functioning of third parties, so you should not rule out the possibility of implementing more “extensive” integration tests.
Contract Test
Distributed systems are highly susceptible to communication breakdowns when a service changes its API or the way it handles requests and responses. If a provider changes its interface, there is a risk that consumers that depend on that service will no longer be able to communicate correctly, resulting in application-level failures. Contract tests solve this problem.
Contract tests are the type of automated test that serves precisely to minimize these risks by verifying that the two systems (consumer and producer) interact in accordance with a pre-established contract. This “contract” (or “pact”) defines the rules and expectations of communication between the two parties: what data can be sent, what responses are expected, and what errors can be handled.
The focus of these tests is on the interface compatibility between systems, rather than the internal functioning of each system. In particular, contract tests are often used in microservice architectures or API-based applications, where independent services need to communicate with each other via HTTP calls or messages.
Contract tests are often considered redundant compared to integration tests, but when dealing with complex systems where multiple components need to communicate with each other, they are very useful because they allow you to anticipate issues. An integration test requires that all services and their dependencies are operational, which can be complex and time-consuming. Contract tests, on the other hand, can be run on individual components, even before the entire system is complete.
End-to-End Testing (E2E Testing)
End-to-end testing is designed to simulate the entire lifecycle of the application, verifying that all parts of the system work correctly from start to finish. The goal is to test the entire flow, from user interaction to communication between various components of the system, including the backend and frontend. These tests are more complex and time-consuming, but they ensure that the application works correctly as an integrated whole.
For example, for an e-commerce application, an E2E test might simulate a user navigating the site, adding products to the cart, making a payment, and receiving an order confirmation. The goal of the test is to ensure that all steps work correctly and without errors.
E2E tests are especially useful in complex scenarios where many parts of the system interact with each other. However, because they can be more expensive and slower than unit or integration tests, it is important to use them strategically.
Load Testing
Load testing is a type of performance testing designed to verify the behavior of a system under a specific load, that is, a simulated number of users or concurrent requests. This type of testing helps to identify how the system responds to various levels of load and which resources are being stressed the most (such as CPU, RAM or network).
The goal of load testing is not only to discover the breaking point of the system but also to analyze how performance degrades when the load increases. These tests allow you to identify any structural or configuration limitations that could negatively impact the user experience.
Load testing offers numerous benefits for companies that develop web applications or software systems:
- By identifying bottlenecks and areas of inefficiency, load testing allows you to optimize the performance of the system, improving the user experience.
- By predicting how the system behaves under high load, you can avoid service interruptions during traffic peaks.
- Determining how many resources (server, CPU, memory) are needed to handle a given volume of traffic enables capacity planning.
- Modern applications must be able to scale rapidly. Load testing helps you assess the scalability of your system and prepare for any sudden increases in traffic.
Security Testing
Security testing is a set of techniques and methodologies used to evaluate the security of an application or system. The main purpose is to identify potential vulnerabilities that could be exploited by hackers or malicious actors to access data or disrupt services.
These tests simulate various types of attacks that a system could suffer, such as malicious code injection, brute force attacks, cross-site scripting (XSS) or denial-of-service (DoS) attacks. The results of these tests provide guidance on how to improve the security of the application and prevent future threats.
Automated testing in the software lifecycle
The DevOps methodology has transformed the way companies develop, release and manage software. This methodology focuses on the integration between development (Dev) and operations (Ops) teams to improve collaboration and accelerate release cycles. In this context, automated testing plays a fundamental role, as it allows to ensure the quality of the software at every stage of the development process.
Testing can be performed at different stages of the development cycle:
- Continuous Integration (CI): Every time a new code is published to the repository, automated tests are run to detect any integration issues.
- Continuous Delivery (CD): Automated tests are run at every stage of the release, ensuring that the software is stable before going into production.
- Post-Release Monitoring: After the release, tests are run to gather feedback and identify any issues that may arise in the real environment.
Automated testing is one of the most important practices in modern software engineering. Effectively implementing it helps ensure that your code is robust, scalable, and bug-free, significantly improving the overall quality of your product. Each type of automated testing has its own specific role in ensuring that your software runs safely and efficiently.