diff --git a/src/test/coins_tests.cpp b/src/test/coins_tests.cpp
--- a/src/test/coins_tests.cpp
+++ b/src/test/coins_tests.cpp
@@ -291,6 +291,8 @@
 // duplicate coinbase tx has the expected effect (the other duplicate is
 // overwritten at all cache levels)
 BOOST_AUTO_TEST_CASE(updatecoins_simulation_test) {
+    SeedInsecureRand(/* deterministic */ true);
+
     bool spent_a_duplicate_coinbase = false;
     // A simple map to track what we expect the cache stack to represent.
     std::map<COutPoint, Coin> result;