diff --git a/src/core/model/test.cc b/src/core/model/test.cc
index 8b992a86f..5c85b16fa 100644
--- a/src/core/model/test.cc
+++ b/src/core/model/test.cc
@@ -19,6 +19,7 @@
 
 #include "abort.h"
 #include "assert.h"
+#include "config.h"
 #include "des-metrics.h"
 #include "log.h"
 #include "singleton.h"
@@ -351,6 +352,7 @@ TestCase::Run(TestRunnerImpl* runner)
     NS_LOG_FUNCTION(this << runner);
     m_result = new Result();
     m_runner = runner;
+    Config::Reset();
     DoSetup();
     m_result->clock.Start();
     for (auto i = m_children.begin(); i != m_children.end(); ++i)
@@ -366,6 +368,7 @@ TestCase::Run(TestRunnerImpl* runner)
 out:
     m_result->clock.End();
     DoTeardown();
+    Config::Reset();
     m_runner = nullptr;
 }
 
diff --git a/src/core/model/test.h b/src/core/model/test.h
index 50e95a22d..380eaf1f9 100644
--- a/src/core/model/test.h
+++ b/src/core/model/test.h
@@ -1234,7 +1234,12 @@ class TestCase
 
     // methods called by TestRunnerImpl
     /**
-     * \brief Actually run this TestCase
+     * \brief Executes DoSetup(), DoRun(), and DoTeardown() for the TestCase
+     *
+     * Config::Reset() is called at both the beginning and end of this method
+     * so that any changes to attribute default values (Config::SetDefault(...))
+     * or global values (e.g., RngRun) that are made within the test case's
+     * DoRun() method do not propagate beyond the scope of running the TestCase.
      *
      * \param [in] runner The test runner implementation.
      */