diff --git a/tests/fortran_error/CMakeLists.txt b/tests/fortran_error/CMakeLists.txt
index d159abf199334ebc3fe51caf9233fe1cd083758b..4e25c3e8b3b3076801cbc76f4e99cd620b378d19 100644
--- a/tests/fortran_error/CMakeLists.txt
+++ b/tests/fortran_error/CMakeLists.txt
@@ -1,4 +1,5 @@
 # The VTK error test case, where the output directory is not accessible.
+include(FindUnixCommands)
 set(OUT_DIR vtk_outline)
 add_test(
     NAME fortran_error_vtk_setup