Scenarios

Scenarios let you define multiple sets of setups on a single mock and switch between them at runtime. This is useful when the collaborator behaves differently depending on its internal state — for example a connection that starts disconnected, becomes connected after Connect(), and times out after a failure.

A mock always has an active scenario (the empty string "" by default). When a member is accessed, Mockolate looks for a matching setup in the active scenario first, then falls back to the default scope.

Defining scenarios

Use InScenario(name) to scope setups to a named scenario. It returns a scope whose Setup property mirrors sut.Mock.Setup but targets the scenario's bucket:

sut.Mock.InScenario("disconnected").Setup.Ping().Throws<TimeoutException>();
sut.Mock.InScenario("connected").Setup.Ping().Returns(true);

A callback overload batches multiple setups into the same scenario:

sut.Mock.InScenario("connected", scope =>
{
    scope.Setup.Ping().Returns(true);
    scope.Setup.Send(It.IsAny<string>()).Returns(true);
});

Setups registered via InScenario do not leak into the default scope.

Switching scenarios

Chain .TransitionTo(name) on any method, property, indexer, or event subscription/unsubscription setup to change the active scenario when the setup fires. The transition runs as a parallel side-effect — it does not replace the return value or throw behaviour.

sut.Mock.InScenario("disconnected")
    .Setup.Connect()
    .Returns(true)
    .TransitionTo("connected");

sut.Mock.InScenario("connected")
    .Setup.Ping()
    .Throws<TimeoutException>()
    .TransitionTo("disconnected");

You can also change the active scenario manually via sut.Mock.TransitionTo("connected");, which is useful for arranging the starting state.

Resolution rules

When dispatching a call, Mockolate looks up setups in this order:

1. The active scenario's bucket (if non-empty).
2. The default bucket (setups registered via sut.Mock.Setup.*).
3. The mock's default behaviour.

Scenario setups add to, rather than replace, the default scope — register catch-alls in the default scope and override specific members per scenario.