Add unit test for Punycode

Author: MasterJ93

Tests/ATSyntaxToolsTests/PunyCodeTests.swift

@@ -0,0 +1,47 @@
+//
+//  PunyCodeTests.swift
+//  ATSyntaxTools
+//
+//  Created by Christopher Jr Riley on 2025-05-18.
+//
+
+import Foundation
+import Testing
+@testable import ATSyntaxTools
+
+@Suite("Punycode Tests") struct PunyCodeTests {
+
+    @Test("Get valid punycode.", arguments: PunycodeStrings.validStrings)
+    func getValidPunycode(input: String, output: String) async throws {
+        let encoded = try Punycode.encodeDomain(input)
+
+        try #require(encoded == output, "Encoded string should match expected output.")
+
+        let decoded = try Punycode.decodeDomain(encoded)
+
+        #expect(decoded == input, "Decoded string should match original input.")
+    }
+
+    public enum PunycodeStrings {
+        public static let validStrings: [(input: String, output: String)] = {
+            return [
+                (input: "hello", output: "hello"),
+                (input: "1234567890", output: "1234567890"),
+                (input: "user-name", output: "user-name"),
+                (input: "my.domain", output: "my.domain"),
+                (input: "bücher", output: "xn--bcher-kva"),
+                (input: "mañana", output: "xn--maana-pta"),
+                (input: "façade", output: "xn--faade-zra"),
+                (input: "smörgåsbord", output: "xn--smrgsbord-82a8p"),
+                (input: "δοκιμή", output: "xn--jxalpdlp"),
+                (input: "пример", output: "xn--e1afmkfd"),
+                (input: "مثال", output: "xn--mgbh0fb"),
+                (input: "דוגמה", output: "xn--6dbbec0c"),
+                (input: "テスト", output: "xn--zckzah"),
+                (input: "🫂", output: "xn--619h"),
+                (input: "🍕.com", output: "xn--vi8h.com"),
+                (input: "🫠sss🍿.com", output: "xn--sss-ke13b05r.com")
+            ]
+        }()
+    }
+}