Microservices Testing: Key Strategies and Tools

Increasingly, development teams are choosing microservices architecture over monolithic architectures in order to enhance application agility, scalability, and maintainability. With this decision to switch to a modular software architecture – where each service is a separate module with its own logic and database that communicates with other modules through APIs – comes the need for new testing strategies and new testing tools.

Testing microservices is an important part of the process of implementing microservices: you need to make sure that your code doesn’t break within the module, that the dependencies in the microservices keep working (and run quickly), and that your APIs meet specified contracts. However, since many microservices are built using continuous delivery mode to build and deploy features consistently, developers and DevOps teams need rigorous and reliable testing strategies to trust these features.

So what different types of tests exist for microservices, how might they work in other areas of your software, and what are their benefits? The well-known “test pyramid” can provide a testing framework for approaching these tests.

According to Martin Fowler, a prominent author on Principles of Software Engineering, the “test pyramid” is a metaphor for grouping software tests into groups with different details. “

test pyramid

The different layers of the pyramid are known as:

  • Unit tests: Test a small part of a service, such as a class.
  • Component tests: Check the behavior of individual services.
  • Integration tests: Verify that a service can interact with infrastructure services, such as databases and other application services, by testing service adapters.

Note: Some versions of the test hierarchy alter the order of component tests and integration tests.

  • Comprehensive tests: Check the behavior of the entire application.

Combining multiple microservices testing strategies results in high test coverage and confidence in your software while making end-to-end maintenance more manageable.

Experiment unit

Unit testing aims to ensure that the smallest part of a service works as expected, within the specifications that were defined during the design phase of the microservices. Since microservices break down an application’s functionality into hundreds of testable microfunction components, unit testing deals with each of them individually and independently. It is a best practice to do unit testing at the level of a class or the level of a group of related classes.

Unit testing can break dependencies of a component by using multiples of testing such as fakes, wedges, dummies, and spies. For example, testers can mock your dependencies’ responses and “assuming they do” [X]” where [X] are the correct response, the failure response, etc.

Ingredients Test

Component testing verifies that a particular service is working properly. With the limited scope of part of the entire microservice architecture, component testing checks the overall functionality of the selected microservices (which can consist of a few classes) by isolating the service within the system, replacing its dependencies with double-testing and/or mock services.

You can create test environments for each component that will be divided into test cases. It may include resource behavior testing, for example, such as performance testing, identifying memory leaks, structural testing, etc.

integration test

Integration testing verifies that independently developed components/microservices function correctly when connected. It tests communication paths and interactions between components and finds errors.

Integration tests are getting more difficult and time consuming to write and run. Therefore, having excellent quality assurance (QA) production practices will help ensure this runs smoothly.

contract test

It is very important to call test nodes in the test pyramid. The contact test checks the compatibility of separate units (such as two small services), by making sure that they are able to communicate with each other. Contract testing checks how APIs work, which is how microservices interact with each other.

Contract testing checks the boundaries and interactions of these microservices and stores them in a contract, which can then be used as a benchmark for how both parties will interact in the future. It requires both parties to agree on the set of permissible interactions and allows for evolution over time.

comprehensive test

Comprehensive testing (E2E testing) is the final testing phase that includes end-to-end testing of the application workflow for complete user journeys.

These tests can be automated, but E2E testing is only done for critical streams. It doesn’t scale well in microservices architecture because it requires you to rotate and connect many microservices, which is challenging to automate and maintain. As a result, it is reserved for testing only significant interactions between specific microservices.

Microservices testing tools for use, including on-demand staging environments

Developers and QA teams have different preferences for microservices testing tools, especially for these different types of tests. Below is a summary of some of the most famous. Many of them are on-demand staging environments, dynamically generated, and powered by the CI/CD pipeline. With on-demand staging, once the developer has finished the staging environment, the staging environment is destroyed, along with any configuration, environment, or installation inconsistencies.

release environments

This platform is an on-demand launch environment, with accessible sharing capabilities for collaboration. You can connect your app repositories to release, which then creates ephemeral environments with every pull request and updates with every code push. In addition, environments can be created for integration, traditional staging, or QA/UAT use cases. Developers and QA have full access to environments for testing and debugging, and product teams, design teams, and stakeholders can see features evolve and provide feedback early and often.

WebApp.io (formerly LayerCI)

WebApp.io is a code review automation platform that allows on-demand review environments for full-stack web applications. You can create custom withdrawal requests. Once you’ve created one copy of your data stack, you can immediately iterate to run e2e tests automatically and integrate into CI/CD workflows. WebApp will automatically suspend your pull request in GitHub, GitLab, or BitBucket.


Vercel is a cloud platform for front-end frameworks, serverless functionality, and static sites, designed to integrate with pre-existing content and databases. It hosts websites and web services that publish instantly and expand automatically and require no supervision, all without configuration. It also provides edge site hosting and caching. It is similar to Amazon Web Services (AWS) Lambda or Netlify.


Pact is a code-first consumer contract testing tool for developers and testers who do coding. Tests HTTP and messaging integrity using contract tests – a method of verifying that messages between applications conform to a common understanding, and are documented in nodes. This method of contract testing reduces testing of large units.

Apache Gamer

Apache JMeter is a commonly used Java-based performance testing tool for testers. It is available as an open source platform, and can be used as a load testing tool to analyze and benchmark the performance of web applications.


Hoverfly is an automated open source communication API simulator dedicated to integration tests. Users can test how the APIs interact in scenarios such as rate limits and/or latency in the network.


Grafana offers free metrics visualization and analytics. The dashboard allows developers to view time series data to see how microservices respond to real-time traffic.


Gatling is a pregnancy test tool written in Scala. It can run simulations on multiple platforms and then reports on metrics such as active user numbers and response times.


Testing, debugging, and maintaining microservices is often the most challenging but essential part of working with a microservice architecture. I hope the information above helps you understand the different types of tests and the best tools for the job.


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