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

1 files changed, 31 insertions, 0 deletions

diff --git a/src/test/fuzz/random.cpp b/src/test/fuzz/random.cpp
new file mode 100644
index 0000000000..7df6594ad6
--- /dev/null
+++ b/src/test/fuzz/random.cpp
@@ -0,0 +1,31 @@
+// 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 <random.h>
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/fuzz.h>
+#include <test/fuzz/util.h>
+
+#include <algorithm>
+#include <cstdint>
+#include <string>
+#include <vector>
+
+void test_one_input(const std::vector<uint8_t>& buffer)
+{
+    FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
+    FastRandomContext fast_random_context{ConsumeUInt256(fuzzed_data_provider)};
+    (void)fast_random_context.rand64();
+    (void)fast_random_context.randbits(fuzzed_data_provider.ConsumeIntegralInRange<int>(0, 64));
+    (void)fast_random_context.randrange(fuzzed_data_provider.ConsumeIntegralInRange<uint64_t>(FastRandomContext::min() + 1, FastRandomContext::max()));
+    (void)fast_random_context.randbytes(fuzzed_data_provider.ConsumeIntegralInRange<size_t>(0, 1024));
+    (void)fast_random_context.rand32();
+    (void)fast_random_context.rand256();
+    (void)fast_random_context.randbool();
+    (void)fast_random_context();
+
+    std::vector<int64_t> integrals = ConsumeRandomLengthIntegralVector<int64_t>(fuzzed_data_provider);
+    Shuffle(integrals.begin(), integrals.end(), fast_random_context);
+    std::shuffle(integrals.begin(), integrals.end(), fast_random_context);
+}