diff --git a/cppad.spec b/cppad.spec
index 32e5603..5492a87 100644
--- a/cppad.spec
+++ b/cppad.spec
@@ -65,8 +65,15 @@ as a single web page, in both HTML and XML, can be found at that web site.
 %setup -q 
 includedir=%{buildroot}%{_includedir}
 
+# Replace cppad_SOURCE_DIR by the system include directory so that
+# installed files, instead of local files, are used for testing.
+sed \
+-e "s|\(INCLUDE_DIRECTORIES(\).*{cppad_SOURCE_DIR}|\1 SYSTEM $includedir|" \
+	-i.stamp CMakeLists.txt
+
 # This patch should not longer be necessary when %%{version} >= 20130000.2
-sed -e '/TARGET_LINK_LIBRARIES/d' -i.stamp speed/example/CMakeLists.txt
+sed -e '/TARGET_LINK_LIBRARIES/d' \
+	-i.stamp speed/example/CMakeLists.txt
 
 # change example/example.cpp to print out machine epsilon 
 cat << EOF > example.sed
@@ -92,9 +99,12 @@ make %{?_smp_mflags}
 
 %install
 rm -rf %{buildroot}
-make check
 make install DESTDIR=%{buildroot}
 
+# use the installed include files to compile and run the tests
+%check
+make check
+
 %clean
 # cleanup 
 rm -rf %{buildroot}