Extract Nostr into a dedicated module

localPackages/Nostr/Tests/Bech32Tests.swift

@@ -0,0 +1,41 @@
+import Testing
+import Foundation
+@testable import Nostr
+
+@Suite("Bech32")
+struct Bech32Tests {
+    @Test("Round-trip encode/decode")
+    func roundTrip() throws {
+        let original = Data([0xde, 0xad, 0xbe, 0xef, 0xca, 0xfe])
+        let encoded = try Bech32.encode(hrp: "test", data: original)
+        let decoded = try Bech32.decode(encoded)
+        #expect(decoded.hrp == "test")
+        #expect(decoded.data == original)
+    }
+
+    @Test("HRP is preserved")
+    func hrpPreserved() throws {
+        let data = Data(repeating: 0x42, count: 32)
+        let encoded = try Bech32.encode(hrp: "npub", data: data)
+        #expect(encoded.hasPrefix("npub1"))
+        let decoded = try Bech32.decode(encoded)
+        #expect(decoded.hrp == "npub")
+    }
+
+    @Test("Decoding invalid checksum throws")
+    func invalidChecksum() throws {
+        var encoded = try Bech32.encode(hrp: "test", data: Data([1, 2, 3]))
+        // Corrupt the last character
+        encoded = String(encoded.dropLast()) + (encoded.last == "q" ? "p" : "q")
+        #expect(throws: Bech32.Bech32Error.self) {
+            try Bech32.decode(encoded)
+        }
+    }
+
+    @Test("Decoding string without separator throws")
+    func missingSeparator() {
+        #expect(throws: Bech32.Bech32Error.self) {
+            try Bech32.decode("noseparatorhere")
+        }
+    }
+}