diff --git a/lib/cpp/test/TSocketInterruptTest.cpp b/lib/cpp/test/TSocketInterruptTest.cpp
index 366242f..a546c23 100644
--- a/lib/cpp/test/TSocketInterruptTest.cpp
+++ b/lib/cpp/test/TSocketInterruptTest.cpp
@@ -53,6 +53,7 @@
 BOOST_AUTO_TEST_CASE(test_interruptable_child_read) {
   TServerSocket sock1("localhost", 0);
   sock1.listen();
+  BOOST_CHECK(sock1.isOpen());
   int port = sock1.getPort();
   TSocket clientSock("localhost", port);
   clientSock.open();