Fix tests and Add tests

Protocol/src/include/protocol/protocol.hxx

@@ -19,6 +19,7 @@ struct SignedMessage {
                     std::string plaintext);
 
       std::vector<uint8_t> serialize();
+      // bool valid();
 };
 
 } // namespace Protocol

Protocol/tests/test_protocol.cxx

@@ -4,7 +4,7 @@
 #include <sodium.h>
 
 TEST_CASE("SignedMessage", "[protocol]") {
-      SECTION("sodium init") REQUIRE(sodium_init() >= 0);
+      REQUIRE(sodium_init() >= 0);
 
       unsigned char pub_key[crypto_sign_PUBLICKEYBYTES];
       unsigned char priv_key[crypto_sign_SECRETKEYBYTES];
@@ -13,9 +13,30 @@ TEST_CASE("SignedMessage", "[protocol]") {
       auto msg = Protocol::SignedMessage(pub_key, priv_key, "Hello, world!");
       auto to_be_signed = msg.serialize();
 
-      SECTION("signed message") {
+      SECTION("valid signed message") {
             REQUIRE(
                 crypto_sign_verify_detached(msg.signature, to_be_signed.data(),
                                             to_be_signed.size(), pub_key) == 0);
       }
+
+      SECTION("tampered invalid signed message") {
+            // todo: use to msg.valid()
+            SECTION("plaintext") {
+                  msg.plaintext = "Hello, world111111";
+                  to_be_signed = msg.serialize();
+                  REQUIRE_FALSE(crypto_sign_verify_detached(
+                                    msg.signature, to_be_signed.data(),
+                                    to_be_signed.size(), pub_key) == 0);
+            }
+
+            SECTION("timestamp") {
+                  msg.timestamp = std::chrono::system_clock::now()
+                                      .time_since_epoch()
+                                      .count();
+                  to_be_signed = msg.serialize();
+                  REQUIRE_FALSE(crypto_sign_verify_detached(
+                                    msg.signature, to_be_signed.data(),
+                                    to_be_signed.size(), pub_key) == 0);
+            }
+      }
 }