strongly typed mock model constructor for Swift tests

ModelFactory.swift

struct MockFile<T> {
    let fileName: String

    init(_ fileName: String) {
        self.fileName = fileName
    }
}

struct Mocks {
    static let UserWithProfile = MockFile<User>("registrations_mock")
    static let Locations = MockFile<[Location]>("locations_mock")
}

func model<T: Model>(file: MockFile<T>) -> T {
    return T.self(fromResponseBody: jsonMock(file.fileName))
}

func models<T: Model>(file: MockFile<[T]>) -> [T] {
    return T.modelsFromResponseBody(jsonMock(file.fileName)) as [T]
}

////

let user = model(Mocks.UserWithProfile)