How do approaches to testing monolithic applications differ from those based on microservice architecture?

Testing monolithic applications and microservices systems differs in several aspects:

• Scope and isolation: In monoliths, tests often cover the entire large codebase, whereas in microservices, they focus on individual services, allowing for more isolated testing.
• Types of tests: For microservices, integration and contract tests between services are important, while in monoliths, more attention is paid to unit and system tests.
• Testing environment: Microservices require setting up complex infrastructure (containers, orchestration) to simulate service interactions.
• Automation and CI/CD: Microservices often require more complex pipelines for testing and deploying individual services.

Example: In a microservices architecture, it is important to test each service's API separately and verify that contracts between services are maintained, whereas in a monolith, more monolithic integration tests covering multiple components at once can be run.