diff --git a/test/unit/org/apache/cassandra/cql3/PreparedStatementsTest.java b/test/unit/org/apache/cassandra/cql3/PreparedStatementsTest.java
index d88507149f..c8688c1bc4 100644
--- a/test/unit/org/apache/cassandra/cql3/PreparedStatementsTest.java
+++ b/test/unit/org/apache/cassandra/cql3/PreparedStatementsTest.java
@@ -22,6 +22,7 @@
 import java.util.stream.Collectors;
 
 import org.junit.Before;
+import org.junit.BeforeClass;
 import org.junit.Test;
 
 import com.datastax.driver.core.Cluster;
@@ -29,6 +30,7 @@
 import com.datastax.driver.core.ResultSet;
 import com.datastax.driver.core.Session;
 import com.datastax.driver.core.exceptions.SyntaxError;
+import org.apache.cassandra.config.DatabaseDescriptor;
 import org.apache.cassandra.db.ConsistencyLevel;
 import org.apache.cassandra.exceptions.PreparedQueryNotFoundException;
 import org.apache.cassandra.index.StubIndex;
@@ -49,6 +51,18 @@ public class PreparedStatementsTest extends CQLTester
                                                     " WITH REPLICATION = { 'class' : 'SimpleStrategy', 'replication_factor' : 1 };";
     private static final String dropKsStatement = "DROP KEYSPACE IF EXISTS " + KEYSPACE;
 
+
+    /**
+     * Prevent the {@link org.apache.cassandra.cql3.statements.schema.TuneUpReplicationFactor} from
+     * uptuning the replication factor to ensure that the test can reliably check the assertions.
+     */
+    @BeforeClass
+    public static void setUpClass()
+    {
+        DatabaseDescriptor.setUptuningEnabled(false);
+        CQLTester.setUpClass();
+    }
+
     @Before
     public void setup()
     {
diff --git a/test/unit/org/apache/cassandra/triggers/TriggersTest.java b/test/unit/org/apache/cassandra/triggers/TriggersTest.java
index 2cf0e84ee4..80c87b6174 100644
--- a/test/unit/org/apache/cassandra/triggers/TriggersTest.java
+++ b/test/unit/org/apache/cassandra/triggers/TriggersTest.java
@@ -25,6 +25,7 @@
 import org.junit.Test;
 
 import org.apache.cassandra.SchemaLoader;
+import org.apache.cassandra.config.DatabaseDescriptor;
 import org.apache.cassandra.schema.Schema;
 import org.apache.cassandra.cql3.QueryProcessor;
 import org.apache.cassandra.cql3.UntypedResultSet;
@@ -59,6 +60,7 @@ public static void beforeTest() throws ConfigurationException
     public void setup() throws Exception
     {
         StorageService.instance.initServer(0);
+        DatabaseDescriptor.setUptuningEnabled(false);
 
         String cql = String.format("CREATE KEYSPACE IF NOT EXISTS %s " +
                                    "WITH REPLICATION = {'class': 'SimpleStrategy', 'replication_factor': 1}",