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

pkg/cryptography/hmac_test.go

@@ -0,0 +1,80 @@
+package cryptography
+
+import (
+	"testing"
+)
+
+func TestGenerateHMACKey(t *testing.T) {
+	testSizes := []int{16, 32, 64}
+	for _, size := range testSizes {
+		t.Run("Size"+string(rune(size)), func(t *testing.T) { // Simple name conversion
+			key, err := GenerateHMACKey(size)
+			if err != nil {
+				t.Fatalf("GenerateHMACKey(%d) failed: %v", size, err)
+			}
+			if len(key) != size {
+				t.Errorf("GenerateHMACKey(%d) returned key of length %d; want %d", size, len(key), size)
+			}
+
+			// Check if key is not all zeros (basic check for randomness)
+			isZero := true
+			for _, b := range key {
+				if b != 0 {
+					isZero = false
+					break
+				}
+			}
+			if isZero {
+				t.Errorf("GenerateHMACKey(%d) returned an all-zero key", size)
+			}
+		})
+	}
+}
+
+func TestComputeAndValidateHMAC(t *testing.T) {
+	key, err := GenerateHMACKey(32) // Use SHA256 key size
+	if err != nil {
+		t.Fatalf("Failed to generate HMAC key: %v", err)
+	}
+
+	message := []byte("This is a test message.")
+
+	// Compute HMAC
+	computedHMAC := ComputeHMAC(key, message)
+	if len(computedHMAC) != 32 { // SHA256 output size
+		t.Errorf("ComputeHMAC returned HMAC of length %d; want 32", len(computedHMAC))
+	}
+
+	// Validate correct HMAC
+	if !ValidateHMAC(key, message, computedHMAC) {
+		t.Errorf("ValidateHMAC failed for correctly computed HMAC")
+	}
+
+	// Validate incorrect HMAC (tampered message)
+	tamperedMessage := append(message, byte('!'))
+	if ValidateHMAC(key, tamperedMessage, computedHMAC) {
+		t.Errorf("ValidateHMAC succeeded for tampered message")
+	}
+
+	// Validate incorrect HMAC (tampered key)
+	wrongKey, _ := GenerateHMACKey(32)
+	if ValidateHMAC(wrongKey, message, computedHMAC) {
+		t.Errorf("ValidateHMAC succeeded for incorrect key")
+	}
+
+	// Validate incorrect HMAC (tampered HMAC)
+	tamperedHMAC := append(computedHMAC[:len(computedHMAC)-1], ^computedHMAC[len(computedHMAC)-1])
+	if ValidateHMAC(key, message, tamperedHMAC) {
+		t.Errorf("ValidateHMAC succeeded for tampered HMAC")
+	}
+
+	// Validate empty message
+	emptyMessage := []byte("")
+	emptyHMAC := ComputeHMAC(key, emptyMessage)
+	if !ValidateHMAC(key, emptyMessage, emptyHMAC) {
+		t.Errorf("ValidateHMAC failed for empty message")
+	}
+	if ValidateHMAC(key, message, emptyHMAC) {
+		t.Errorf("ValidateHMAC succeeded comparing non-empty message with empty HMAC")
+	}
+}