Agile & TDD Best Practices for APIs: API Microservices Using TDD

APIs vs Microservices

·       An API is a contract between a caller and an application underlying data and functionality

·       APIs can be public (web based) or private

·       Web APIs usually send data in JSON or XML

·       Common API methods – GET, POST, PUT, DELETE

 

 

·       Microservices often include APIs

·       Microservices are multiple component services that can be combined to create a software solution

·       Microservices are decentralized and may have decentralized data

·       Microservices are self-contained and have dedicated data sources

 

TDD

·       Mock services can be used to mock REST APIs

·       TDD allows clients to test APIs before the coding is completed

·       TDD API design process:

o   Tests are written based on scenarios and required functionality

o   A REST API mock service is created for running the test scenarios

o   Tests are run on mock services

o   The real APIs are created and run against the test scenarios

 

REST API Mocking

Tools for REST API mocking: Nock, MockServer, Beeceptor, Mockoon

Behavior driven development (BDD) API design

·       BDD is an agile development approach

·       API design steps:

o   Select a small unit of work, brainstorm and reach a consensus of API work to be done

o   Document and track the API examples from the brainstorming session using automation tools

o   Implement the API web service behavior described in each example and create a unit test to guide the implementation

·       BDD involves all stakeholders, hence it allow for a shared understanding of the problem domain, documentation is created in general language, increases collaboration

·       BDD supports better communication between technical and non-technical people

·       Natural language specifications and real-world examples are used in BDD

·       Tests generated in natural language are automated in BDD

Software testing techniques

·       REST API testing

o   Functional software testing

o   Security testing

·       Load testing

o   Determine the maximum number of concurrent users

o   Infrastructure stress tests check the server and network architecture

o   Maximum operation capacity captures the total number of operations performed

·       Database testing

o   Structural testing to validate the architecture database

o   Functional testing validates mapping between fields and functions

o   Non-functional (example – security testing, load testing)

·       Unit testing

 

 

Software testing tools

o   Web testing platforms – Katalon Studio web testing tools (for validation testing, error detection testing and functional testing, SOAP UI REST API testing)

o   SOAP and REST API testing tools

o   Tools for unit testing

 

Integration testing

3 methods to write -> Create test (to setup the resources such as the DB), read test and delete test (to clean up the resources such as DB)

Tools – Postman