Add unit tests for configuration, cryptography, interfaces, and packet handling.

pkg/cryptography/curve25519_test.go

@@ -0,0 +1,63 @@
+package cryptography
+
+import (
+	"bytes"
+	"testing"
+
+	"golang.org/x/crypto/curve25519"
+)
+
+func TestGenerateKeyPair(t *testing.T) {
+	priv1, pub1, err := GenerateKeyPair()
+	if err != nil {
+		t.Fatalf("GenerateKeyPair failed: %v", err)
+	}
+
+	if len(priv1) != curve25519.ScalarSize {
+		t.Errorf("Private key length is %d, want %d", len(priv1), curve25519.ScalarSize)
+	}
+	if len(pub1) != curve25519.PointSize {
+		t.Errorf("Public key length is %d, want %d", len(pub1), curve25519.PointSize)
+	}
+
+	// Generate another pair, should be different
+	priv2, pub2, err := GenerateKeyPair()
+	if err != nil {
+		t.Fatalf("Second GenerateKeyPair failed: %v", err)
+	}
+	if bytes.Equal(priv1, priv2) {
+		t.Error("Generated private keys are identical")
+	}
+	if bytes.Equal(pub1, pub2) {
+		t.Error("Generated public keys are identical")
+	}
+}
+
+func TestDeriveSharedSecret(t *testing.T) {
+	privA, pubA, err := GenerateKeyPair()
+	if err != nil {
+		t.Fatalf("GenerateKeyPair A failed: %v", err)
+	}
+	privB, pubB, err := GenerateKeyPair()
+	if err != nil {
+		t.Fatalf("GenerateKeyPair B failed: %v", err)
+	}
+
+	secretA, err := DeriveSharedSecret(privA, pubB)
+	if err != nil {
+		t.Fatalf("DeriveSharedSecret (A perspective) failed: %v", err)
+	}
+
+	secretB, err := DeriveSharedSecret(privB, pubA)
+	if err != nil {
+		t.Fatalf("DeriveSharedSecret (B perspective) failed: %v", err)
+	}
+
+	if !bytes.Equal(secretA, secretB) {
+		t.Errorf("Derived shared secrets do not match:\nSecret A: %x\nSecret B: %x", secretA, secretB)
+	}
+
+	if len(secretA) != curve25519.PointSize { // Shared secret length
+		t.Errorf("Shared secret length is %d, want %d", len(secretA), curve25519.PointSize)
+	}
+}