diff --git a/test-suite/libv2-demo/CMakeLists.txt b/test-suite/libv2-demo/CMakeLists.txt
index dfdc9654..0d417820 100644
--- a/test-suite/libv2-demo/CMakeLists.txt
+++ b/test-suite/libv2-demo/CMakeLists.txt
@@ -3,7 +3,7 @@ set_property(DIRECTORY APPEND
 )
 
 set(test_names
-		lib-gas-opt-pllel
+		lib-gas-opt
 		libc-gas-mix-serial
 		libc-gas-mix-serial-clash
 )
diff --git a/test-suite/libv2-demo/lib-gas-opt-pllel/CMakeLists.txt b/test-suite/libv2-demo/lib-gas-opt/CMakeLists.txt
similarity index 60%
rename from test-suite/libv2-demo/lib-gas-opt-pllel/CMakeLists.txt
rename to test-suite/libv2-demo/lib-gas-opt/CMakeLists.txt
index c29fffba..37ab722a 100644
--- a/test-suite/libv2-demo/lib-gas-opt-pllel/CMakeLists.txt
+++ b/test-suite/libv2-demo/lib-gas-opt/CMakeLists.txt
@@ -3,5 +3,8 @@ project(demo_Wannier90 LANGUAGES Fortran)
 
 find_package(Wannier90 REQUIRED)
 
-add_executable(demo demo.f90)
+add_executable(demo demo.F90)
+if (Wannier90_MPI)
+	target_compile_definitions(demo PRIVATE Wannier90_MPI)
+endif ()
 target_link_libraries(demo PRIVATE Wannier90::wannier90)
diff --git a/test-suite/libv2-demo/lib-gas-opt-pllel/demo.f90 b/test-suite/libv2-demo/lib-gas-opt/demo.F90
similarity index 96%
rename from test-suite/libv2-demo/lib-gas-opt-pllel/demo.f90
rename to test-suite/libv2-demo/lib-gas-opt/demo.F90
index 7743fa5f..0b80d152 100644
--- a/test-suite/libv2-demo/lib-gas-opt-pllel/demo.f90
+++ b/test-suite/libv2-demo/lib-gas-opt/demo.F90
@@ -1,5 +1,7 @@
 program ok
+#ifdef Wannier90_MPI
   use mpi_f08
+#endif
   use w90_library
 
   implicit none
@@ -18,6 +20,11 @@ program ok
   real(8) :: uccart(3, 3) ! cartesian unit cell
   type(lib_common_type), target :: w90main
 
+#ifndef Wannier90_MPI
+  ! MPI dummy
+  integer :: mpi_comm_world = 0
+#endif
+
   ! collect data
   nb = 12
   nw = 8
@@ -58,10 +65,12 @@ program ok
     enddo
   enddo
 
+#ifdef Wannier90_MPI
   ! setup MPI
   call mpi_init(ierr)
   call mpi_comm_size(mpi_comm_world, mpisize, ierr)
   call mpi_comm_rank(mpi_comm_world, mpirank, ierr)
+#endif
 
   ! crude k distribution
   allocate (distk(nk))
@@ -125,5 +134,7 @@ program ok
       write (stdout, '(4f20.10)') (w90main%wannier_data%centres(ic, ib), ic=1, 3), w90main%wannier_data%spreads(ib)
     enddo
   endif
+#ifdef Wannier90_MPI
   call mpi_finalize()
+#endif
 end program
diff --git a/test-suite/libv2-demo/lib-gas-opt-pllel/gaas.amn b/test-suite/libv2-demo/lib-gas-opt/gaas.amn
similarity index 100%
rename from test-suite/libv2-demo/lib-gas-opt-pllel/gaas.amn
rename to test-suite/libv2-demo/lib-gas-opt/gaas.amn
diff --git a/test-suite/libv2-demo/lib-gas-opt-pllel/gaas.eig b/test-suite/libv2-demo/lib-gas-opt/gaas.eig
similarity index 100%
rename from test-suite/libv2-demo/lib-gas-opt-pllel/gaas.eig
rename to test-suite/libv2-demo/lib-gas-opt/gaas.eig
diff --git a/test-suite/libv2-demo/lib-gas-opt-pllel/gaas.mmn b/test-suite/libv2-demo/lib-gas-opt/gaas.mmn
similarity index 100%
rename from test-suite/libv2-demo/lib-gas-opt-pllel/gaas.mmn
rename to test-suite/libv2-demo/lib-gas-opt/gaas.mmn
diff --git a/test-suite/libv2-demo/lib-gas-opt-pllel/makefile b/test-suite/libv2-demo/lib-gas-opt/makefile
similarity index 75%
rename from test-suite/libv2-demo/lib-gas-opt-pllel/makefile
rename to test-suite/libv2-demo/lib-gas-opt/makefile
index 25571f21..16ef2e4e 100644
--- a/test-suite/libv2-demo/lib-gas-opt-pllel/makefile
+++ b/test-suite/libv2-demo/lib-gas-opt/makefile
@@ -5,5 +5,5 @@ XLIBS=$(ROOT)/libwan2.a
 a.out: demo.o 
 	$(MPIF90) demo.o $(LIBS) $(XLIBS)
 demo.o: demo.f90
-	$(MPIF90) $(FCOPTS) $(XINCS) -c $<
+	$(MPIF90) $(FCOPTS) -DWannier90_MPI $(XINCS) -c $<