The microservice architecture raises quite some challenges when it comes to testing. These challenges sometimes happen as a side effect of the architecture, the poor testing strategy, or the inexperience with the microservices architecture. The following are some of the challenges that make microservices testing a complex procedure:

• Incomplete knowledge of the microservices: For integration testing and debugging of issues inside an application built over microservices architecture, the tester responsible for writing the tests for the application needs to have complete knowledge about the infrastructure and the individual microservices. Without this knowledge, the tester is unable to write tests that can cover all the possible request flows inside an application that may result in some of the bugs escaping during the testing phase.
• Poor coordination: In the development of microservices, there are multiple teams that own their set of microservices, and are usually working on their pace. This may cause an issue in the coordination and can delay the testing of the application in case a microservice, on which there are certain dependencies, has still not come out of the development phase.
• Increased complexity: For an application that has only a small number of microservices, the testing is usually easy. But this testing becomes more and more cumbersome as the number of microservices powering an application increases. This is because now, the testers are supposed to write tests for the increased number of request flows, and also to make sure that the different API endpoints function as intended.
• High flexibility: Microservices allow for increased flexibility. As a developer, we are free to choose a technology stack that is going to power a particular microservice. The same thing adds to the increased issues for the testing of the application because now, the tests need to take into account the different types of components that are being used to power a particular microservice.

The preceding points are a few challenges that make the work of testing the microservices a challenging task. However, every problem comes with a solution, and so do these challenges. Let's take a look at the possible workarounds we have to overcome these challenges, outlined as follows:

• Implement release schedules: The teams responsible for building an application can commit to a schedule for the release of application in terms of Milestone. At every stage in the Milestone, some of the services are made available for testing based on the priority of the service to be deployed. This helps in improving the team's coordination.
• Standardize the API endpoints: Every service needs to expose a set of APIs that it uses for taking in a request and generating a response. Standardizing the APIs and defining what parameters a particular API endpoint may require helps a lot during the testing phase, where the testers can now mock a service easily, even if the service is not yet available for testing.
• Standardize development practices: Although every team that is responsible for the development of a particular microservice is free to use any set of tools for the development of microservice, it is usually a good practice to standardize the set of tools and technologies that may be used by a team so as to avoid unnecessary complexity inside the infrastructure.
• Integration of DevOps practices: As the shift to microservices architecture happens, the DevOps practices should also be adopted, which aims to make the teams responsible for the complete life cycle of the microservice they are developing. This not only helps in speeding up the development process, but also allows for thorough testing of the microservices before they are deployed in production.

Now, we are aware of what kind of changes the process requires for the testing of the microservices architecture. This allows us to plan our strategy ahead, and make sure that the services are well-tested before they are deployed into the production environment.

With the knowledge of testing in place, it's now time to understand a very important concept in the area of microservices that allows us to understand how the individual services are behaving in production.  This also allows us to figure out where exactly a particular request inside a microservices-based application is failing. So, let's take a deep dive into this concept.