fix io_service incomplete type compile errors

refs #4425

Change-Id: I8969593ae00fb78d4ae9e686b133bca134accb22
diff --git a/tests/integrated/test-basic-interest-read.cpp b/tests/integrated/test-basic-interest-read.cpp
index 2c96d1d..8028894 100644
--- a/tests/integrated/test-basic-interest-read.cpp
+++ b/tests/integrated/test-basic-interest-read.cpp
@@ -24,6 +24,7 @@
 #include "../repo-storage-fixture.hpp"
 #include "../dataset-fixtures.hpp"
 
+#include <boost/asio/io_service.hpp>
 #include <boost/test/unit_test.hpp>
 
 namespace repo {