Legacy test helpers

Older Reventless code tests business logic through per-kind helper modules — BehaviorTest, ProjectionTest, EventMappingTest — each with its own vocabulary for setting up prior events, dispatching, and asserting.

Write new tests as scenarios instead. The Given/When/Then DSL covers every slice kind with one shared vocabulary, resolves the spec and DSL from the filename, and runs under both Jest and its own CLI runner. It is the supported path, and the one the plugin generator and the example plugins use.

This page exists so that a test you meet in older code is not a mystery. If you are adding to a file that still uses these helpers, adding to it is fine; converting the file to scenarios is better, and mechanical — the setup, dispatch, and assertion steps map one to one.

Where the equivalents are

Legacy helper	Scenario DSL
BehaviorTest (aggregate command handling)	Behavior_GWT / StateChangeSlice_GWT
ProjectionTest (event → state)	Projection_GWT / StateViewSlice_GWT
EventMappingTest (cross-entity reactions)	Mapping_GWT / Automation_GWT

The verbs line up: prior events become givenEvents, dispatch becomes whenCmd or whenEvent, and the assertion becomes thenEvents, thenState, or thenError. See the shared vocabulary for the full table.

Running them

Both kinds compile to .res.mjs and run under Jest with the ESM flag — see Running tests. Nothing about the runner changes when you convert a file.