Generate setHandler method for actor based test-double

[fummicc1]

Motivation

When mockable protocol inherits Actor, its should be actor-isolated.
When we use that mock-class, setting handler method is not easy because we can't update actor-isolated properties from test site. This can be solved by adding setHandler methods for actor mock-class.

/// @mockable
protocol P: Actor {
    func f()
}

will generate:

>

Before	After
actor PMock: P { init() { } private(set) var fCallCount = 0 var fHandler: (() -> ())? func f() { fCallCount += 1 if let fHandler = fHandler { fHandler() } } }	actor PMock: P { init() { } private(set) var fCallCount = 0 var fHandler: (() -> ())? func setFHandler(_ handler: (() -> ())?) { fHandler = handler } func f() { fCallCount += 1 if let fHandler = fHandler { fHandler() } } }

I think setFHandler is helpful for users to set mock implementation.

Implementation

If output test-double is actor, mockolo also renders like the following:

func setFooHandler(_ handler: ((String) async -> Result<String, Error>)?) {
    fooHandler = handler
}

To classify if test-double is class or actor, I added new property mockDeclKind to RenderContext.

[sidepelican]

LGTM