Pengujian Kontrak Antar-Micro Frontend

Unit tests check one MFE in isolation; E2E tests are slow and brittle. Contract testing fills the gap by verifying the agreements between MFEs without running everything together.

A contract is the shape of an interaction between two parties — the exposed module signature, an event payload, or a shared state shape. Both sides must agree on it.

In consumer-driven contract testing, the consumer defines what it expects from a provider. The provider then verifies it actually meets those expectations.

For micro frontends, contracts commonly cover:

• Exposed module props/signatures
• Custom event names and payloads
• Shared state structure
• Shared API response shapes

If a remote exposes a Widget, the consumer expects specific props. The contract records those expectations explicitly.

The consumer writes a test describing the interface it relies on, generating a contract artifact the provider can check against.

The provider runs a verification test confirming its exposed module still satisfies every consumer contract before it deploys.

For event-based communication, the contract pins the event name and payload schema, so renaming an event or dropping a field is caught immediately.

Store contracts in a shared location (a broker or repo) both teams can access. Tools like Pact provide a broker; a shared schema package is a simpler alternative.

Run provider contract verification in CI on every change. A broken contract fails the build before the incompatible MFE can reach production.

Contract tests give you:

• Fast feedback without full integration
• Confidence to deploy independently
• Early detection of breaking interface changes
• Clear, documented interfaces between teams

You learned contract testing for MFEs:

• Contracts capture agreements on props, events, and state
• Consumers define expectations; providers verify them
• Store contracts in a broker or shared schema
• Run verification in CI to block breaking changes
• Enables confident independent deployment

Contract tests are the fast middle layer of the MFE testing pyramid.