diff --git a/test/unit/imaging/image_io_test.cpp b/test/unit/imaging/image_io_test.cpp
index 47966f42c..f2463f810 100644
--- a/test/unit/imaging/image_io_test.cpp
+++ b/test/unit/imaging/image_io_test.cpp
@@ -2,6 +2,7 @@
 
 #include <iostream>
 #include <cstring>
+#include <mapnik/color.hpp>
 #include <mapnik/image.hpp>
 #include <mapnik/image_reader.hpp>
 #include <mapnik/image_util.hpp>