9 files changed, 46 insertions, 15 deletions
diff --git a/src/test/bloom_tests.cpp b/src/test/bloom_tests.cpp
index 514b325b2d..4a7ad9b38b 100644
--- a/src/test/bloom_tests.cpp
+++ b/src/test/bloom_tests.cpp
@@ -461,7 +461,7 @@ static std::vector<unsigned char> RandomData()
 
 BOOST_AUTO_TEST_CASE(rolling_bloom)
 {
-    SeedInsecureRand(/* deterministic */ true);
+    SeedInsecureRand(SeedRand::ZEROS);
     g_mock_deterministic_tests = true;
 
     // last-100-entry, 1% false positive:
diff --git a/src/test/coins_tests.cpp b/src/test/coins_tests.cpp
index 7ad276df96..436c1bffa0 100644
--- a/src/test/coins_tests.cpp
+++ b/src/test/coins_tests.cpp
@@ -279,7 +279,7 @@ UtxoData::iterator FindRandomFrom(const std::set<COutPoint> &utxoSet) {
 // has the expected effect (the other duplicate is overwritten at all cache levels)
 BOOST_AUTO_TEST_CASE(updatecoins_simulation_test)
 {
-    SeedInsecureRand(/* deterministic */ true);
+    SeedInsecureRand(SeedRand::ZEROS);
     g_mock_deterministic_tests = true;
 
     bool spent_a_duplicate_coinbase = false;
diff --git a/src/test/cuckoocache_tests.cpp b/src/test/cuckoocache_tests.cpp
index 87b32eef1a..119d4b3295 100644
--- a/src/test/cuckoocache_tests.cpp
+++ b/src/test/cuckoocache_tests.cpp
@@ -29,7 +29,7 @@ BOOST_AUTO_TEST_SUITE(cuckoocache_tests);
  */
 BOOST_AUTO_TEST_CASE(test_cuckoocache_no_fakes)
 {
-    SeedInsecureRand(true);
+    SeedInsecureRand(SeedRand::ZEROS);
     CuckooCache::cache<uint256, SignatureCacheHasher> cc{};
     size_t megabytes = 4;
     cc.setup_bytes(megabytes << 20);
@@ -47,7 +47,7 @@ BOOST_AUTO_TEST_CASE(test_cuckoocache_no_fakes)
 template <typename Cache>
 static double test_cache(size_t megabytes, double load)
 {
-    SeedInsecureRand(true);
+    SeedInsecureRand(SeedRand::ZEROS);
     std::vector<uint256> hashes;
     Cache set{};
     size_t bytes = megabytes * (1 << 20);
@@ -118,7 +118,7 @@ template <typename Cache>
 static void test_cache_erase(size_t megabytes)
 {
     double load = 1;
-    SeedInsecureRand(true);
+    SeedInsecureRand(SeedRand::ZEROS);
     std::vector<uint256> hashes;
     Cache set{};
     size_t bytes = megabytes * (1 << 20);
@@ -181,7 +181,7 @@ template <typename Cache>
 static void test_cache_erase_parallel(size_t megabytes)
 {
     double load = 1;
-    SeedInsecureRand(true);
+    SeedInsecureRand(SeedRand::ZEROS);
     std::vector<uint256> hashes;
     Cache set{};
     size_t bytes = megabytes * (1 << 20);
@@ -285,7 +285,7 @@ static void test_cache_generations()
     // iterations with non-deterministic values, so it isn't "overfit" to the
     // specific entropy in FastRandomContext(true) and implementation of the
     // cache.
-    SeedInsecureRand(true);
+    SeedInsecureRand(SeedRand::ZEROS);
 
     // block_activity models a chunk of network activity. n_insert elements are
     // added to the cache. The first and last n/4 are stored for removal later
diff --git a/src/test/pmt_tests.cpp b/src/test/pmt_tests.cpp
index 717e8c4cab..bf58bd63b9 100644
--- a/src/test/pmt_tests.cpp
+++ b/src/test/pmt_tests.cpp
@@ -30,7 +30,6 @@ BOOST_FIXTURE_TEST_SUITE(pmt_tests, BasicTestingSetup)
 
 BOOST_AUTO_TEST_CASE(pmt_test1)
 {
-    SeedInsecureRand(false);
     static const unsigned int nTxCounts[] = {1, 4, 7, 17, 56, 100, 127, 256, 312, 513, 1000, 4095};
 
     for (int i = 0; i < 12; i++) {
diff --git a/src/test/sighash_tests.cpp b/src/test/sighash_tests.cpp
index 903ef0b0a9..2c56bbdbb0 100644
--- a/src/test/sighash_tests.cpp
+++ b/src/test/sighash_tests.cpp
@@ -119,8 +119,6 @@ BOOST_FIXTURE_TEST_SUITE(sighash_tests, BasicTestingSetup)
 
 BOOST_AUTO_TEST_CASE(sighash_test)
 {
-    SeedInsecureRand(false);
-
     #if defined(PRINT_SIGHASH_JSON)
     std::cout << "[\n";
     std::cout << "\t[\"raw_transaction, script, input_index, hashType, signature_hash (result)\"],\n";
diff --git a/src/test/streams_tests.cpp b/src/test/streams_tests.cpp
index c6a6e8752b..177d8fda73 100644
--- a/src/test/streams_tests.cpp
+++ b/src/test/streams_tests.cpp
@@ -338,7 +338,7 @@ BOOST_AUTO_TEST_CASE(streams_buffered_file)
 BOOST_AUTO_TEST_CASE(streams_buffered_file_rand)
 {
     // Make this test deterministic.
-    SeedInsecureRand(true);
+    SeedInsecureRand(SeedRand::ZEROS);
 
     for (int rep = 0; rep < 50; ++rep) {
         FILE* file = fsbridge::fopen("streams_test_tmp", "w+b");
diff --git a/src/test/util/setup_common.cpp b/src/test/util/setup_common.cpp
index 2099684809..0c6ecdf69d 100644
--- a/src/test/util/setup_common.cpp
+++ b/src/test/util/setup_common.cpp
@@ -34,6 +34,27 @@
 const std::function<std::string(const char*)> G_TRANSLATION_FUN = nullptr;
 
 FastRandomContext g_insecure_rand_ctx;
+/** Random context to get unique temp data dirs. Separate from g_insecure_rand_ctx, which can be seeded from a const env var */
+static FastRandomContext g_insecure_rand_ctx_temp_path;
+
+/** Return the unsigned from the environment var if available, otherwise 0 */
+static uint256 GetUintFromEnv(const std::string& env_name)
+{
+    const char* num = std::getenv(env_name.c_str());
+    if (!num) return {};
+    return uint256S(num);
+}
+
+void Seed(FastRandomContext& ctx)
+{
+    // Should be enough to get the seed once for the process
+    static uint256 seed{};
+    static const std::string RANDOM_CTX_SEED{"RANDOM_CTX_SEED"};
+    if (seed.IsNull()) seed = GetUintFromEnv(RANDOM_CTX_SEED);
+    if (seed.IsNull()) seed = GetRandHash();
+    LogPrintf("%s: Setting random seed for current tests to %s=%s\n", __func__, RANDOM_CTX_SEED, seed.GetHex());
+    ctx = FastRandomContext(seed);
+}
 
 std::ostream& operator<<(std::ostream& os, const uint256& num)
 {
@@ -42,12 +63,13 @@ std::ostream& operator<<(std::ostream& os, const uint256& num)
 }
 
 BasicTestingSetup::BasicTestingSetup(const std::string& chainName)
-    : m_path_root(fs::temp_directory_path() / "test_common_" PACKAGE_NAME / strprintf("%lu_%i", (unsigned long)GetTime(), (int)(InsecureRandRange(1 << 30))))
+    : m_path_root{fs::temp_directory_path() / "test_common_" PACKAGE_NAME / std::to_string(g_insecure_rand_ctx_temp_path.rand32())}
 {
     fs::create_directories(m_path_root);
     gArgs.ForceSetArg("-datadir", m_path_root.string());
     ClearDatadirCache();
     SelectParams(chainName);
+    SeedInsecureRand();
     gArgs.ForceSetArg("-printtoconsole", "0");
     InitLogging();
     LogInstance().StartLogging();
diff --git a/src/test/util/setup_common.h b/src/test/util/setup_common.h
index 5467cd6cce..1e2e059a56 100644
--- a/src/test/util/setup_common.h
+++ b/src/test/util/setup_common.h
@@ -39,9 +39,21 @@ extern FastRandomContext g_insecure_rand_ctx;
  */
 extern bool g_mock_deterministic_tests;
 
-static inline void SeedInsecureRand(bool deterministic = false)
+enum class SeedRand {
+    ZEROS, //!< Seed with a compile time constant of zeros
+    SEED,  //!< Call the Seed() helper
+};
+
+/** Seed the given random ctx or use the seed passed in via an environment var */
+void Seed(FastRandomContext& ctx);
+
+static inline void SeedInsecureRand(SeedRand seed = SeedRand::SEED)
 {
-    g_insecure_rand_ctx = FastRandomContext(deterministic);
+    if (seed == SeedRand::ZEROS) {
+        g_insecure_rand_ctx = FastRandomContext(/* deterministic */ true);
+    } else {
+        Seed(g_insecure_rand_ctx);
+    }
 }
 
 static inline uint32_t InsecureRand32() { return g_insecure_rand_ctx.rand32(); }
diff --git a/src/test/util_tests.cpp b/src/test/util_tests.cpp
index 974106adc4..daf6d951bc 100644
--- a/src/test/util_tests.cpp
+++ b/src/test/util_tests.cpp
@@ -1106,7 +1106,7 @@ BOOST_AUTO_TEST_CASE(util_IsHexNumber)
 
 BOOST_AUTO_TEST_CASE(util_seed_insecure_rand)
 {
-    SeedInsecureRand(true);
+    SeedInsecureRand(SeedRand::ZEROS);
     for (int mod=2;mod<11;mod++)
     {
         int mask = 1;