Effective Dart/Flutter Integration Testing

What Integration Tests Verify

Integration tests validate that multiple components work correctly together. They sit between unit tests (isolated) and E2E tests (full app on device).

Unit Test:     [ServiceA] alone
Integration:   [ServiceA] → [ProviderB] → [ServiceC] working together  
E2E (device):  Full app on real device/emulator

Core Principles

1. Test the Real Dependency Chain

Integration tests should use real implementations wherever possible, only mocking external boundaries (network, file system, native plugins).