Useful Techniques in Microservices Testing

Overall, most organizations deploy their microservices in container-based environments like Docker. Hence, QA teams use a wider variety of techniques for testing microservices. For instance, microservices testing teams do not necessarily need to test components together (as is in monolith applications). Instead, they can divide and test individual application modules or components.

To that end, here are some of the useful techniques used in testing microservices:

1. Using Test Dependencies

Instead of test doubles, a microservices testing environment can use real test dependencies. For instance, here are some scenarios of how microservices communicate in any test environment:

2. Unit Testing

In this type of testing, QA teams can check the performance of each unit (or component) of the microservices-based application. Depending on the product complexity, a unit can mean a single object, module, function, or method. This technique is suited to test smaller units in the microservice.

Typically, application developers must perform unit testing during the product development phase. Nevertheless, QA teams can execute unit testing later to check each component of the microservice architecture.

3. Contract Testing

Contract testing is crucial for testing loosely coupled microservice components. This technique ensures all components are communicating efficiently. A contract defines the result expected for a specific input. Every service call must meet the defined contract even after modifying the service.

Contract testing checks every service independently and, accordingly, verifies their responses. In the case of any service dependencies, services must behave as a stub, which enables a service to function without interacting with other services.

4. Integration Testing

Integration testing is necessary to test microservices together as a complete system. This ensures that microservices are efficiently working and collaborating during execution. Using integration testing, QA teams can design communication paths and identify any incorrect assumptions in each microservice.

Integration testing is also effective in testing interactions of microservices with external tools or components. For example, it can verify if the data cache integrates properly with external data sources.

5. End-to-End (E2E) Testing

E2E testing for microservices can verify if all its components work properly across the complete user journey. In short, E2E testing is useful for checking if the overall application meets its business objectives. Furthermore, for microservices-based applications, E2E testing ensures that there are no gaps between various microservices. For instance, to check if messages between services are conveyed properly or if network firewalls are properly configured.

6. Service Virtualization

Also known as “over the wire” or remote testing, service virtualization involves the practice of replacing real & dependent components with their test versions. Using service virtualization tools, organizations can create a simulation-like experience without involving developers and QA teams.

How does service virtualization “mock” a service? Firstly, it needs a microservice with the required URLs. Secondly, the URLs must accept the data and respond based on the microservice specifications.

How can ACCELQ help in testing microservices? Let’s discuss that next.