Introduction To Contract Testing and Getting Started With Postman
An insight into contract testing!
The software testers get new challenges with microservices and containerization. An interdependency between microservices and containers makes the software systems more complex. Moreover, each function of the service has its independent life cycle and versions. This further adds to the difficulty of the software testers, especially the integration testers. So what are the solutions that can help to combat such challenges? One of the best ways to combat such challenges is consumer-driven contract testing.
What is contract testing? How is it performed?
Contract testing helps to ensure that various services, like a client or an API provider, can communicate in the best possible way. They connect the provider and a consumer. This consumer can be a client who wants to receive some credential information from an app. Similarly, a provider can be an API on a server. But in a microservice architecture, the communication methods are different. Moreover, the hierarchy of roles is not used in such a system.
What is consumer-driven contract testing?
The process of contract testing helps the testers to ensure that service works in the best possible way between an API provider and a consumer.
But when do you need to perform consumer-driven contract testing? This happens when the provider changes the part of the service. In such a case, you should know whether the consumer can still use the service or not. Moreover, you should also know whether the changes still meet the requirements of the consumer. For all this, you need to perform consumer-driven contract testing.
But before the providers can make any changes, they should obtain permission from the consumers.
This is because these Contacts are written only by consumers. Moreover, consumers only manage these contracts. Before implementing new features, the providers have to conduct their research. This research is aimed at checking whether the different categories of consumers would be affected by the changes. They can do this by looking at the status of the consumers’ contract tests.
What are contract testing tools?
Contract testing is a comparatively newer term. There are several contract testing tools. These tools include Pact, API blueprint, OpenAPI, postman collections, RAML, etc.
But what are these tools used for? And which is the best contract testing tool? The contract testing tools help to create specifications for API. They also help in publishing current API behavior. They can statically publish this behavior with documentation.
Out of the above-mentioned tools, Pact and Postman, are the real specialists. The pact is mainly aimed at contract testing. On the other hand, Postman has a large community. This further makes this platform more appealing.
Postman for Consumer-driven contract testing
You should always start with Postman when implementing contract testing. This is because Postman is easy to use along with other automation tools such as different software suites.
How does it work?
There are many ways to run the postman collections. These collections are specifications of an API.
You can run the collections in the following ways-
- You can run these collections on your local machine by using the Postman app
- You can also run these collections in the command line.
- Apart from the above two points, you can also run these collections on CI systems with the help of Newman or cloud using monitors.
Besides this, the testers can also add dynamic behavior to their requests. They can execute response assertions in the tests. You can even find detailed instructions for documenting the behavior in Postman. You can do this by going through different online articles that help you to know the transitioning from manual to automated API testing. With such articles, you can easily share your contract collections with your team automatically. This saves the time and effort required to share these contract collections manually.
Consumer-driven contract test with the postman
Develop the blueprint
In the beginning, you need to create a collection with every Postman API test. This collection will help you to visualize the API structure. You can get the details of the collection from the provider of the service who is being visualized. This collection is known as the blueprint.
Making contract collections
Now you can create contract collections from the blueprint and the server. Besides this, Postman has several other interesting features as well. For example, you can create the correct response headers, body, and time. You can create such features based on the assertions that you had created earlier in the test.
Contract testing services: Let’s wrap it up!
Thus, the best way to combat the challenges of testing microservices is to use consumer-driven contract testing. This method helps to ensure that the service between the API provider and the consumer functions in the best possible way. Using consumer-driven contract testing, you can make sure that the communication between the consumer and API provider happens smoothly and in a lucid way.
The process of consumer-driven contract testing also helps to maintain the consumer in control. There are several different tools available for automating the process of consumer-driven contract testing. But Postman is an excellent option among the plethora of different tools. This is because of its intuitive and versatile user interface.
By the end of this article, you must know the answers to various questions like what is contract testing, what are the contract testing services, what are the different contract testing tools, what is a test pyramid, which is the best contract testing tool and why should we use Postman for consumer-driven contract testing. But if you have any queries, you can always mention down in the comments section below.