4 Practical Microservices Testing Strategies for Enterprises

The ever-changing business needs of organizations have triggered a significant shift in enterprise service-based architectures throughout the last few years. In the context of software design allied to dynamic, automated systems, IT infrastructure, as well as more focused smaller services, “microservices architecture” has the potential to become a commodity infrastructure design pattern.

Microservices is not a new architecture model in the industry. The evolution of microservices has brought many benefits for companies seeking private enterprise-level cloud solutions, such as the capability of breaking down big applications into minute, composable services, scaling and maintaining each component independently, and parallelizing development process across multiple teams. However, the real challenge lies in testing microservices that present a set of difficulties due to their distributed and independent nature. This blog post will illustrate various effective methodologies that can be successfully employed to overcome the challenges one encounters while testing multiple independently deployable components. So without further ado, let’s get down to business.

1. Unit Testing

The scope of unit testing can be sociable or solitary concerning a service. The smaller the unit will be under test, the easier it is to determine the behavior of modules and probe the collaborators as well as interactions between objects and their dependencies. Since the cyclomatic complexity of the unit is inferior, Quality Analysis (QA) engineers can evaluate whether or not the units are isolated from their collaborators by using this testing strategy. Both the sociable and solitary unit testing styles are frequently used simultaneously in the same codebase to tackle different testing issues.

The motive behind testing the domain layer is to emulate DML statements and certify that all collaborators use the real domain objects in correct sequence. During the unit testing, engineers can verify the logic used to generate map responses or other requests from external remote dependencies. As far as resources and service layer are concerned, they validate that each component correctly interacts with its collaborator, thereby monitoring the request/response cycle in a repeatable and consistent manner.

2. Integration Testing

Integration testing takes place in the staging environment to integrate individual services after analyzing the functionality of communication pathways and interactions between them. Unlike monolithic or SOA, microservices architecture depends on the Inter-Process Communication (IPC) mechanism to function appropriately, which is why the interactions between services must be verified.

Automated tests need to be written for mapping out the success and error cases through the integration with external services and data stores. Running gateway integration tests will defect interface errors, such as incorrect SSL handling and missing HTTP headers, at the protocol level. And the persistence integration test ensures that each component and protocol client must respond as an external dependency in case of timeouts and partial failures.

3. Contract Testing

Contract testing is a sort of a black box that verifies the contract between an external service call and its API provider endpoint. There are two types of contract testing, including:

• Integration contract testing
• Consumer-driven contract testing

In integration contract testing, each component needs to be called independently, and it must meet the contract agreement anticipated by a consuming service. The best way to deal with this is to carry out a test against the double. On a side note, it’s critical to run a separate set of tests periodically to confirm that there are no changes against your test doubles. However, a failure in these tests can slow down the deployment pipeline and disrupt the functionality of an IT infrastructure or distributed system. One best possible way to handle intermittent test failures is by updating your test doubles, and probably the code too so as to bring them back into high coherence and consistency with external services.

In consumer-driven contract testing, consumers will delineate the way in which they want to consume a service. The consumer contracts can be made in a mutually consented language and schema between the producer and consumer. The service providers will test a service against the replicas of the individual contracts, and then make changes to that particular service without impacting the nature of other services.

4. End-to-End Testing

End-to-End (E2E) testing ascertains that the overall system is accurately working as well as the network infrastructure (load balancers, firewall, and more) is correctly configured. E2E tests, however, need to be run at the finest coarse granularity possible to test the functionality of the entire system. In this, QA engineers verify the behavior of the fully-integrated process and make sure that the system collectively meets its business requirements, regardless of the Service Component Architecture in use. With the help of functional testing, developers can determine if an integrated system or app functions as stated in the requirements.