Context Lifetimes

There are three lifetimes or “scopes” that exist during a StorEvil run.

The lifetime of a context class can be set by using the “Lifetime” parameter on the Context Attribute.

[StorEvil.Context(Lifetime=StorEvil.ContextLifetime.Scenario)]
public class ExampleContextThatLivesForOneScenario { }

There are three possible settings for lifetime:

Scenario (default)

A new instance of the context class will be created for each scenario. Within a scenario, the same instance will be used. For scenario outlines, a new instance is created for each example.

Story

A new instance of the context class will be created for each story (plaintext specification/feature file). Within a story, the same instance will be reused in each scenario.

Session

A single instance of the context class will be created for the entire run. This is intended for use with, for example, setting up a Selenium or WATiN session, or initializing a database to a known state.

Dependencies between context classes.

StorEvil will do simple constructor injection of dependent contexts.

What this means is that any parameters to the constructor of a context object will be created when the context class is created.
These context instances, like all others, are shared between any classes reference them.

You can have one context that depends on another, or share a context class that is not used to parse grammar between contexts.

In this example, the UserAssertions and AdminUserContext context classes use the UserTestContext to store the state of the system as each step is executed.

The UserTestContext will be created when either of these classes is created (when any line matches a method in either class).

[StorEvil.Context]
public class AdminUserContext {
    public AdminUserContext(UserTestContext user) {
        _user = user;
    }

    public void Given_user_has_superuser_privileges() {
        ...
    }
}
[StorEvil.Context]
public class UserAssertions {
    public UserAssertionContext(UserTestContext user) {
        _user = user; // same instance as given to AdminUserContext... one instance per type, per scenario
    }
    public void Then_user_should_be_an_admin() {
        Assert.IsTrue(_user.IsAdministrator);
    }
}

public class UserTestContext {
    public CurrentUserId { get; set; }
    public bool IsAdministrator {get; set; }
}

Notes about Lifetimes in dependent classes

Contexts that depend on other contexts (as constructor parameters) cannot depend on contexts that have a shorter lifetime.
If a context class depends on another that has a shorter lifetime, a ConflictingLifetimeException will be thrown.