[test] use CMake guard for test requiring dune-foamgrid

test/common/boundingboxtree/CMakeLists.txt

@@ -11,7 +11,9 @@ dune_add_test(NAME test_bboxtree_dim3
               SOURCES test_bboxtree.cc
               COMPILE_DEFINITIONS WORLD_DIMENSION=3)
 
-dune_add_test(SOURCES test_geometry_fracture.cc)
+dune_add_test(NAME test_geometry_fracture
+              SOURCES test_geometry_fracture.cc
+              CMAKE_GUARD dune-foamgrid_FOUND)
 
 # symlink the input file in the build directory
 dune_symlink_to_source_files(FILES "network1d.msh" "network2d.msh" "fracture.msh")