danielr / mokka Goto Github PK

Throwing functions can currently be mocked like any other function, but we don't support faking errors for throwing function mocks yet.

This could look something like this:

userServiceMock.createUserFunc.throws(UserError.invalidEmail)

To better integrate with Nimble, we should provide some basic predicates to make matching nicer.

Something like this:

expect(mock.fooFunc).toNot(beCalled())
expect(mock.barFunc).to(beCalledWith(someArgument))

Mocking functions with callbacks usually involves calling the callback with configurable arguments. It would be nice, if Mokka could directly support this.

Something like this could work:

public class CallbackFunctionMock<Args, CallbackArgs, CallbackReturnValue>: FunctionMock<Args> {

    var result: CallbackArgs?
    
    public func recordCall(_ args: Args, _ callback: (CallbackArgs) -> CallbackReturnValue) {
        super.recordCall(args)
        
        if let callbackArgs = result {
            _ = callback(callbackArgs)
        }
    }
}

This would then be used like this:

let doSomethingAsyncFunc = CallbackFunctionMock<String, Int, Void>(name: "doSomethingAsync(arg:completion:)")
func doSomethingAsync(arg: String, completion: (Int) -> Void) {
    doSomethingAsyncFunc.recordCall(arg, completion)
}

There are some open questions, though:

• How to support callbacks with multiple arguments? (Is tuple splat still a thing, or has it been removed in some Swift version?)
• How to support multiple callbacks?
• What about functions that have a callback and a return value?
• Can we somehow get rid of the requirement to separately specify the generic type parameters for the callback arguments and the callback return value? This is not very intuitive.

It would be nice to add dedicated support for mocking methods that return Combine publishers and allow to stub those publishers.