Struct TestHarness 

pub struct TestHarness<A: Actor> { /* private fields */ }

Test harness for synchronous actor testing.

This harness allows testing actors without spawning tasks:

• Messages are queued in a local VecDeque
• Processing is explicit via process_one() or process_all()
• State is directly accessible for assertions

Implementations

impl<A: Actor> TestHarness<A>

pub fn new(actor: A) -> Self

Create a new test harness for the given actor.

pub fn with_state(actor: A, state: A::State) -> Self

Create a new test harness with a pre-initialized state.

This is useful when you want to test specific state transitions without going through the init process.

pub fn send(&mut self, msg: A::Message)

Send a message to the actor’s mailbox.

The message will be queued and processed when process_one() or process_all() is called.

pub fn process_one(&mut self) -> Option<Directive>

Process a single message from the mailbox.

Returns Some(flow) if a message was processed, or None if the mailbox was empty.

pub fn process_all(&mut self) -> Vec<Directive>

Process all messages in the mailbox.

Returns a Vec of all Directive values returned by handle(). Processing stops early if any handler returns Directive::Stop.

pub fn process_until<F>(&mut self, condition: F) -> Vec<Directive>

where F: FnMut(&A::State) -> bool,

Process messages until the mailbox is empty or a condition is met.

Returns the flows from all processed messages.

pub fn idle(&mut self) -> Directive

Call the actor’s idle hook.

This is useful for testing background work behavior.

pub fn post_stop(&mut self)

Call the actor’s post_stop hook.

pub fn state(&self) -> &A::State

Get a reference to the actor’s state.

pub fn state_mut(&mut self) -> &mut A::State

Get a mutable reference to the actor’s state.

pub fn is_empty(&self) -> bool

Check if the mailbox is empty.

pub fn mailbox_len(&self) -> usize

Get the number of messages in the mailbox.

pub fn cancel(&mut self)

Signal cancellation.

pub fn is_cancelled(&self) -> bool

Check if cancelled.