A quick generic fixture reader

Fixture

import Foundation
import XCTest

struct Fixture<T: Decodable & Equatable> {
    let value : T
    init(url: URL) throws {
        let actualData = try Data(contentsOf: url)
        self.value = try JSONDecoder().decode(T.self, from: actualData)
    }
    func assert(_ t:T) {
        XCTAssertEqual(t, value)
    }
}