tests: Add fuzzing harness for functions/classes in protocol.h

src/test/fuzz/protocol.cpp

@@ -0,0 +1,32 @@
+// Copyright (c) 2020 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <optional.h>
+#include <protocol.h>
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/fuzz.h>
+#include <test/fuzz/util.h>
+
+#include <cstdint>
+#include <stdexcept>
+#include <vector>
+
+void test_one_input(const std::vector<uint8_t>& buffer)
+{
+    FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
+    const Optional<CInv> inv = ConsumeDeserializable<CInv>(fuzzed_data_provider);
+    if (!inv) {
+        return;
+    }
+    try {
+        (void)inv->GetCommand();
+    } catch (const std::out_of_range&) {
+    }
+    (void)inv->ToString();
+    const Optional<CInv> another_inv = ConsumeDeserializable<CInv>(fuzzed_data_provider);
+    if (!another_inv) {
+        return;
+    }
+    (void)(*inv < *another_inv);
+}