Microservice Testing: Why Do You Need It?

Similar to lion cubs, a software becomes bigger, heavier, and difficult to control as it grows. Microservices is a software development architecture that helps to resolve this problem by breaking down distinctive features into separate services.

By using service boundaries, microservices isolate every feature into single independent function modules. These modules then work together to provide you with the application you use. Most commonly, developers follow this technique to create web and mobile applications, because it makes your app lighter, robust, fast, and highly scalable.

That said, the microservice architecture presents new challenges in terms of testing. In this article, we will see why microservices testing is necessary for applications and explore ways to implement microservice testing more effectively.

Deconstructing the Microservice Architecture

Traditionally, developers created applications in the monolithic architecture, which organizes software in one large executable program. However, with the growth of mobile and web apps, this architecture has become less possible.

Although the front end of mobile and web apps is still created in a monolithic architecture, the backend database, login, load-balancing, custom, and several other services are connected to the application through microservices, instead of a monolithic backend. Technologies like Docker helps us implement this architecture with the help of containerization.

What Is the Microservice Testing Strategy?

Microservice testing is a specialized testing approach where we implement tests within each microservice’s code. Most modern applications contain several microservices within one application. Therefore, we must mock other microservices when we test every microservice in isolation.

Isolating microservices during testing and leveraging test doubles allows us to minimize complexity and prevents the application from misbehaving when executed. Moreover, since we write tests at the granular level inside the microservice layer, it is easier to test the API behavior from the consumer perspective during the test. Additionally, creating component tests helps testers study the interaction between the database and microservices as a single unit.

Who Do We Need Microservice Testing?

Sinc microservices have a unique architecture, testing microservice applications also requires a unique approach. There are several reasons for that. Firstly, the scale of services in microservices testing is larger than traditional applications.

Most microservice apps use dozens of services simultaneously. As a result, it’s common for services to change from what they were in the staging environment to how they are in the production environment.

Additionally, because microservices must share collective demand as they scale dynamically, we have to create a unique microservice testing strategy for our applications. The way we organize our services also changes how they respond to load dynamically.

Likewise, service paths of your application can change based on which feature users are consuming. Also, a microservice application has countless variables while user requests for every service must traverse through the entire network. All of this can significantly affect the latency and response time of your application, especially if there is already traffic on the network.

Lastly, we can execute functionality calls within the same binary in monolithic applications, something that is not feasible in microservices. Therefore, using the traditional testing approach of implementing unit tests and then testing different modules together through integration tests can be extremely complex in microservices.

This mostly happens because of the distributed nature of the application and how functionality flows through different services. Microservice testing is designed to tests applications with multiple functionalities much more easily.

Things You Should Consider in Your Microservice Testing Strategy

Microservice testing helps identify issues that compromise the performance and stop us from scaling our application. Here are some tips you can follow to improve your microservice testing strategy.

Prioritize High-Risk Services Instead of 100% Coverage

The Pareto Principle dictates us that 80% of our errors are derived from 20% of issues in our application. If applied early in the development cycle long-running tests can create unnecessary hurdles in development. Trying to nail 100% testing coverage too early slows down development significantly, so it’s better to avoid it at that stage.

Instead, you should prioritize the testing of high-risk services, so that you can ensure that critical modules are operating as they should. Doing so can help you accelerate development without compromising your application’s quality.

Leverage Service Virtualization When Functional Dependencies Aren’t Available

Waiting for functional dependencies during testing slows down testing and wastes your valuable time and resources. Instead, you can avoid these delays by leveraging service virtualization. Similar to service mocking, service virtualization allows you to test just with the URLs you need in service instead of waiting for a fully functional microservice.

Use More Than One Runtime Environments

Microservices testing can be extremely time-consuming, especially during load testing. As a result, if you test one microservice, it can hog on all resources, making it difficult to test more than one microservice at a time.

This is why it’s best to avoid dependence on a single run-time environment. You should always use multiple run time environments if you must test several microservices simultaneously. Doing so will minimize the risk of delaying the testing procedure and will help you fast-track microservice testing.

Go Beyond the Request/Response Ratio

During load testing, most testers stubbornly use the response-request ratio as the golden standard of performance. Although the request/response ratio is an essential metric during microservice performance testing, we also have several ways to test the application’s performance. Leveraging other metrics can help you test several critical components of your microservice more comprehensively.

Configure Service Level Agreements through Testing

Service-level agreements dictate the scope of your project and outline the performance metrics for your application. Testing for establishing service level agreements can help you create realistic benchmarks for your application and make application management much easier. Moreover, configuring service level agreements created through testing enables you to address stakeholder complaints more effectively.

Microservice testing ensures that your application is scalable, meets modern standards, and performs seamlessly under heavy user loads. An experienced microservice testing service can help you detect bottlenecks more accurately and implement microservice testing effectively.

Programmers.io has a dedicated Quality Engineering team qualified for effective microservice testing. To learn more about how our service works, contact us directly, or feel free to visit our website.