fix nip04 decryption padding and add tests.

nip04/nip04_test.go

@@ -0,0 +1,47 @@
+package nip04
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestEncryptionAndDecryption(t *testing.T) {
+	sharedSecret := make([]byte, 32)
+	message := "hello hellow"
+
+	ciphertext, err := Encrypt(message, sharedSecret)
+	if err != nil {
+		t.Errorf("failed to encrypt: %s", err.Error())
+	}
+
+	plaintext, err := Decrypt(ciphertext, sharedSecret)
+	if err != nil {
+		t.Errorf("failed to decrypt: %s", err.Error())
+	}
+
+	if message != plaintext {
+		t.Errorf("original '%s' and decrypted '%s' messages differ", message, plaintext)
+	}
+}
+
+func TestEncryptionAndDecryptionWithMultipleLengths(t *testing.T) {
+	sharedSecret := make([]byte, 32)
+
+	for i := 0; i < 150; i++ {
+		message := strings.Repeat("a", i)
+
+		ciphertext, err := Encrypt(message, sharedSecret)
+		if err != nil {
+			t.Errorf("failed to encrypt: %s", err.Error())
+		}
+
+		plaintext, err := Decrypt(ciphertext, sharedSecret)
+		if err != nil {
+			t.Errorf("failed to decrypt: %s", err.Error())
+		}
+
+		if message != plaintext {
+			t.Errorf("original '%s' and decrypted '%s' messages differ", message, plaintext)
+		}
+	}
+}