A Guide to Microservice Testing Strategies: Types, Practices and Tools
Application development in a microservices architecture is accomplished by dividing it into functional units that operate individual processes. These singular functions must address highly erratic user traffic and remain lightweight.
Functions in these microservice environments are updated concurrently, allowing the application to scale up or down and ensure adequate processing power.
Keeping track of these updates to ensure you don’t deploy a microservice with broken code is challenging as the application develops its dynamic network.
Hence, various microservice testing strategies are essential during the software development process.
This article will introduce microservice testing and why it’s essential to your microservice architecture.
We’ll discuss the different testing strategies that exist and their advantages.
Then we’ll look at standard testing best practices and the proper approaches and tools for conducting microservices testing.
What is microservice testing?
Microservice testing is the first step in ensuring that a service works as intended by implementing specific tests on the microservices. Each microservice has its own data store and is deployed independently in a microservice architecture.
These services then work together to provide a fully functional application. As a result, testing, debugging, and managing these multiple independent services is challenging.
Since microservices use a continuous integration/continuous delivery (CI/CD) model to develop and deploy features, developers and DevOps teams consistently require accurate and reliable testing methodologies before releasing new components and features.
Why do we need microservice testing?
Catching Bugs Earlier
Microservice testing is required to guarantee that each individual microservice is functional and meets the desired requirements.
Since microservices are modular and independently deployable, it will be easy to notice any failure in these services.
Hence, making it easy to prevent these errors from having any ripple effect on the overall system.
Facilitates standardization on a company level
Microservice testing ensures that all individual services adhere to the same standards and criteria.
This is crucial in larger organizations where multiple teams work on multiple distributed systems. It contributes to the consistency with which all organizational microservices are developed, tested, and deployed.
By implementing testing strategies, an organization can ensure that all microservices are of high quality, thereby improving the system’s overall reliability and resilience.
You can achieve this through standardized testing frameworks, tools, and established testing strategies and procedures.
Saves development time and money
Thoroughly testing your microservices application before it officially launches helps developers rapidly identify and address any faults or defects.
Thereby saving time and resources that may otherwise be spent troubleshooting and resolving problems in a live production environment.
Types of Microservice Testing
There are different microservices test developers can employ to achieve high test coverage and reliability in their applications.
Here are the five layers of testing.
1. Unit Testing
A unit test focuses on a single class, method, or function that can be tested independently to ensure that individual components work as anticipated. It is an essential backup plan for catching unintended consequences when developers change the code.
Unit testing also alerts developers to the specific location in the code where the broken functionality exists. It is performed during the development phase. Developers can write unit tests using libraries such as Mockito, JUnit, and others to call implementation functions directly.
2. Integration Testing
Integration testing focuses on assembling the components as subsystems to ensure every part fits and works together before production. It tests the communication path between each microservice and external components to find any errors.
Writing and running integration tests can become increasingly complicated and time-consuming. Developers frequently employ a great production QA (quality assurance) technique to ensure everything goes well.
3. Component Testing
A component is any well-encapsulated, coherent, and independently replaceable part of a more extensive system.
In a microservice architecture, the components are the services themselves. Component testing checks the overall functionality of a specific microservice by isolating it from other services and running tests on it.
This can be done using simulated resources or mock services to replace the real ones. Component testing can be done in two ways: in-process and out-of-process.
Ready made solutions such as Bit enable development teams the right architectural structure to isolate components and test them independently.
4. Contract Testing
A contract is used to specify the microservices’ boundaries and interactions. They are also utilized in testing the compatibility of different units (such as two microservices).
As a result, these contracts specify the expected outcomes for certain inputs and serve as a standard for how both parties interact in the future.
Contract testing can be used to verify agreed-upon contracts for APIs and other resources provided by the microservice.
5. End-To-End Testing
End-to-end testing (E2E), also called system testing, examines the complete flow to verify that the entire application works to achieve its business goals.
It is the final testing stage that is used to analyze important user flows from start to finish to ensure their behaviours are as expected.
In the E2E test, the application is fully deployed and treated as a black box, and the test is conducted. This test verifies that the network infrastructure firewalls, proxies, and load balancers are correctly configured.
Since this test necessitates spinning up and trying to connect several microservices, automation and maintenance in a microservices architecture, become complex.
Microservices Testing Strategies
There are advantages and disadvantages to each of these strategies, and the best approach will depend on the specific needs and goals of the organization. As a result, you can tweak each strategy to match your particular needs.
The full stack in-a-box strategy
This strategy involves isolating your local machine from the test environment.
In this method, you replicate a cloud environment locally and test everything in one using the virtual environment created on your device. It can be used to test the entire system in a more realistic environment, but it takes longer to set up.
Stubbed service strategy
This strategy involves creating lightweight, simulated versions of specific microservices that can be used for testing purposes.
This dummy version behaves similarly to the microservice in production, except without any dependencies.
The documentation-first strategy
This strategy involves creating and reviewing your API documentation and test cases for each microservice before testing.
This can help verify that the proposed modifications fulfil the requirements and adhere to the API standards, ensuring that nothing is broken.
Shared Test Instances strategy
Developers can employ this approach by working on their local devices while still accessing a separate, shared instance of a microservice as a point of reference for their local environment.
This results in a more efficient and accurate testing experience.
Microservices Testing Best Practices
Testing microservices can be overwhelming; however, it has many benefits. Here are some best practices for microservice testing:
Use automated testing
Consider automated testing in your microservice architecture to help save time and ensure that tests are consistent and reliable. Leverage the continuous integration and delivery (CI/CD) workflow to automate the testing processes.
Test microservices individually
All services should be tested independently in a similar manner to confirm that they function efficiently on their own. This entails running unit tests on each element.
Combine Multiple tests
Different types of tests are useful for various purposes. And you cannot rely on one test to give you a completely reliable output. Therefore, consider combining unit tests, integration tests, and end-to-end tests to understand the system comprehensively.
Top 8 Tools for Microservice Testing
- Bit: Built-in testing features for microservices and can scale testing across all components used in an application. CI/CD pipelines can be configured to test a component and all of its dependents and/or dependencies.
- VCR: A testing tool for recording and replaying HTTP interactions in your testing process for quick, predictable, and accurate testing.
- Pact: A tool to define consumer-driven “contracts” between microservices and specify each service’s expected input and output.
- JMeter: A Java-based performance testing tool that can be useful for analyzing and examining the scalability and performance of microservices applications.
- Jaeger: An open-source tool used to test, monitor and troubleshoot the root cause of system errors(E2E).
- Locust: An open-source performance testing tool used to perform load testing.
- Hoverfly: Hoverfly is an open-source API simulator used for automated testing. It is used to facilitate integrated testing and simulate communication between APIs.
- WebApp.io: A DevOps platform that has been hyper-optimized to ease webapp CI/CD, E2E testing, and preview environments.
Conclusion
In conclusion, microservice testing is an integral part of ensuring the quality and stability of a microservice-based system.
Although several strategies and tools are available for testing microservices, the best approach depends on your system’s requirements. Implementing the appropriate microservice testing strategies, on the other hand, will help deliver a resilient, scalable, and dependable application.
