test: refactor: Move g_insecure_rand_ctx.Reseed out of the helper that calls MakeRandDeterministicDANGEROUS

The global g_insecure_rand_ctx will be removed in the future, so
removing it from this helper is useful.

Also, tying the two concepts of the global internal RNGState and the
global test-only rng context is a bit confusing, because tests can
simply use the m_rng, if it exists. Also, tests may seed more than one
random context, or none at all, or a random context of a different type.

Fix all issues by moving the Reseed call to the two places where it is
used.

Author: MarcoFalke

src/test/fuzz/fuzz.cpp

@@ -106,7 +106,8 @@ void initialize()
     // randomness during the fuzz test, except:
     // - GetStrongRandBytes(), which is used for the creation of private key material.
     // - Creating a BasicTestingSetup or derived class will switch to a random seed.
-    SeedRandomForTest(SeedRand::ZEROS);
+    SeedRandomStateForTest(SeedRand::ZEROS);
+    g_insecure_rand_ctx.Reseed(GetRandHash());
 
     // Terminate immediately if a fuzzing harness ever tries to create a socket.
     // Individual tests can override this by pointing CreateSock to a mocked alternative.

src/test/util/random.cpp

@@ -15,7 +15,7 @@ FastRandomContext g_insecure_rand_ctx;
 
 extern void MakeRandDeterministicDANGEROUS(const uint256& seed) noexcept;
 
-void SeedRandomForTest(SeedRand seedtype)
+void SeedRandomStateForTest(SeedRand seedtype)
 {
     static const std::string RANDOM_CTX_SEED{"RANDOM_CTX_SEED"};
 
@@ -34,5 +34,4 @@ void SeedRandomForTest(SeedRand seedtype)
     const uint256& seed{seedtype == SeedRand::SEED ? ctx_seed : uint256::ZERO};
     LogPrintf("%s: Setting random seed for current tests to %s=%s\n", __func__, RANDOM_CTX_SEED, seed.GetHex());
     MakeRandDeterministicDANGEROUS(seed);
-    g_insecure_rand_ctx.Reseed(GetRandHash());
 }

src/test/util/random.h

@@ -24,8 +24,8 @@ enum class SeedRand {
     SEED,  //!< Use (and report) random seed from environment, or a (truly) random one.
 };
 
-/** Seed the RNG for testing. This affects all randomness, except GetStrongRandBytes(). */
-void SeedRandomForTest(SeedRand seed = SeedRand::SEED);
+/** Seed the global RNG state for testing and log the seed value. This affects all randomness, except GetStrongRandBytes(). */
+void SeedRandomStateForTest(SeedRand seed);
 
 static inline uint32_t InsecureRand32()
 {

src/test/util/setup_common.h

@@ -65,7 +65,14 @@ struct TestOpts {
 struct BasicTestingSetup {
     util::SignalInterrupt m_interrupt;
     node::NodeContext m_node; // keep as first member to be destructed last
+
     FastRandomContext& m_rng{g_insecure_rand_ctx}; // Alias (reference) for the global, to allow easy removal of the global in the future.
+    /** Seed the global RNG state and m_rng for testing and log the seed value. This affects all randomness, except GetStrongRandBytes(). */
+    void SeedRandomForTest(SeedRand seed = SeedRand::SEED)
+    {
+        SeedRandomStateForTest(seed);
+        m_rng.Reseed(GetRandHash());
+    }
 
     explicit BasicTestingSetup(const ChainType chainType = ChainType::MAIN, TestOpts = {});
     ~BasicTestingSetup();