Make Filters/Sources module MPI independant #19100

MPI tests will be built only if MPI is enabled, without requiring the
whole module to depend on MPI.

Filters/Sources/Testing/Cxx/CMakeLists.txt

@@ -35,18 +35,17 @@ vtk_add_test_cxx(vtkFiltersSourcesCxxTests tests
   TestTextSource.cxx,NO_VALID
   TestTexturedSphereSource.cxx,NO_VALID
   )
-
-vtk_add_test_mpi(vtkFiltersSourcesCxxTests tests_mpi
-  TESTING_DATA
-  TestSpatioTemporalHarmonicsSourceDistributed.cxx
-  )
-
-set(all_tests
-  ${tests}
-  ${tests_mpi}
-  )
-
-vtk_test_cxx_executable(vtkFiltersSourcesCxxTests all_tests
+  
+vtk_test_cxx_executable(vtkFiltersSourcesCxxTests tests
   DISABLE_FLOATING_POINT_EXCEPTIONS
   RENDERING_FACTORY
   )
+  
+if(TARGET VTK::ParallelMPI)
+  vtk_add_test_mpi(vtkFiltersSourcesCxxTests-MPI tests_mpi
+    TESTING_DATA
+    TestSpatioTemporalHarmonicsSourceDistributed.cxx
+    )
+
+  vtk_test_cxx_executable(vtkFiltersSourcesCxxTests-MPI tests_mpi)
+endif()

Filters/Sources/vtk.module

@@ -37,9 +37,10 @@ TEST_DEPENDS
   VTK::IOParallel
   VTK::IOXML
   VTK::InteractionStyle
-  VTK::ParallelMPI
   VTK::RenderingFreeType
   VTK::RenderingOpenGL2
   VTK::RenderingParallel
   VTK::TestingCore
   VTK::TestingRendering
+TEST_OPTIONAL_DEPENDS
+  VTK::ParallelMPI