What is contract testing?
Contract testing is famous in microservices world. When we consider less numbers of microservices, then contract testing is not so necessary.However when you look at the Amazon or Netflix microservices mesh, it is countless. Such cases it is extremely difficult for developer or tester to maintain unit/automation test suite as per the microservices development chnages.
Contract testing is the best possible solution currently offered for this situation. In contract testing, a mocked service is created to represent the provider. There are commercial or opensource tools available to stimulate this. In short, contract is set of predefined requests and responses created by automation or developer team to do their testing.