diff --git a/openexr.spec b/openexr.spec
index 375fe88..1e13d4b 100644
--- a/openexr.spec
+++ b/openexr.spec
@@ -144,9 +144,8 @@ make %{?_smp_mflags}
 %ifarch x86_64
 # tests takes LOONG, e. g. 20 min, in obs even more that
 # exceed timeout limit 25 min
-echo "set_tests_properties(OpenEXR.IlmImf PROPERTIES TIMEOUT 3000)" >> IlmImfTest/CMakeLists.txt
 export LD_LIBRARY_PATH="$PWD/build/IlmImf:$PWD/build/IlmImfUtil:$LD_LIBRARY_PATH"
-%ctest
+%ctest --timeout 3000
 %endif
 
 %post -n libIlmImf%{so_suffix}-%{sonum} -p /sbin/ldconfig