Parsing comment blocks for AB_TEST

ab_test_maintenance.swift

func validateABTests(file: String) {
    let declaredVariantFile = findPath(file)
    let variantContents = contents(atPath: declaredVariantFile)
    let variantTests = regexFor("(.*//\\s*AB_TEST.*)", content: variantContents)

    variantTests.forEach {
        guard let expirationDateSerialized = regexFor("((0|1)\\d{1})/((0|1|2)\\d{1})/((19|20)\\d{2})", content: $0).first,
            let expirationDate = dateFormatter.date(from: expirationDateSerialized) else {
                fatalError("Incorrect expiration date format: MM/dd/yyyy")
        }
        if let expiredTest = regexFor(".+?(?=:)", content: $0).first, expirationDate < currentDate {
            print("warning: \(expiredTest) AB Test is expired - \n:\($0)")
        }
    }

}