diff --git a/testnet/TestEthernetTap.cpp b/testnet/TestEthernetTap.cpp
index f3273d00f..35c7511b4 100644
--- a/testnet/TestEthernetTap.cpp
+++ b/testnet/TestEthernetTap.cpp
@@ -78,9 +78,10 @@ TestEthernetTap::TestEthernetTap(
 
 TestEthernetTap::~TestEthernetTap()
 {
+	static const TestFrame zf;
 	{
 		Mutex::Lock _l(_pq_m);
-		_pq.push(TestFrame()); // 0 length frame = exit
+		_pq.push(zf); // 0 length frame = exit
 	}
 	_pq_c.signal();
 	Thread::join(_thread);
diff --git a/testnet/TestEthernetTap.hpp b/testnet/TestEthernetTap.hpp
index 8b7a5e879..66e219227 100644
--- a/testnet/TestEthernetTap.hpp
+++ b/testnet/TestEthernetTap.hpp
@@ -63,7 +63,7 @@ class TestEthernetTap : public EthernetTap
 private:
 	struct TestFrame
 	{
-		TestFrame() : etherType(0),len(0) {}
+		TestFrame() : from(),to(),etherType(0),len(0) {}
 		TestFrame(const MAC &f,const MAC &t,const void *d,unsigned int et,unsigned int l) :
 			from(f),
 			to(t),