DumpEquatable.swift

extension String {
    init<T>(dumping x: T) {
        self.init()
        dump(x, to: &self)
    }
}

func assertDumpsEqual<T>(_ lhs: @autoclosure () -> T, _ rhs: @autoclosure () -> T, file: StaticString = #file, line: UInt = #line) {
    assert(String(dumping: lhs()) == String(dumping: rhs()), "Expected dumps to be equal.", file: file, line: line)
}

protocol DumpEquatable: Equatable {
    static func areEqual(_ lhs: Self, _ rhs: Self) -> Bool
}

extension DumpEquatable {
    static func == (lhs: Self, rhs: Self) -> Bool {
        let areProbablyEqual = areEqual(lhs, rhs)
        
        if areProbablyEqual {
            assertDumpsEqual(lhs, rhs)
        }
        
        return areProbablyEqual
    }
}

// Example:

struct Person {
    var name: String
    var age: Int
}

extension Person: DumpEquatable {
    static func areEqual(_ lhs: Person, _ rhs: Person) -> Bool {
        return lhs.name == rhs.name
    }
}

let alice1 = Person(name: "Alice", age: 23)
let alice2 = Person(name: "Alice", age: 39)

alice1 == alice2 // assertion failure