Separate the parallel test set from the serial tests

tests/CMakeLists.txt

 enable_testing()
 
-set(Testdirs CuBulk CuBulkXML Fe_1l Fe_1lXML Fe-Atom CuBand CuBandXML CuDOS
-CuDOSXML Fe_bct_LO Fe_bct_LOXML Fe_bct Fe_bctXML PTO PTOXML Fe_fcc Fe_fccXML
-Fe_1l_SOC Fe_1l_SOCXML PTO-SOC PTO-SOCXML Fe_bct_SOC Fe_bct_SOCXML
-GaAsMultiUForceXML TiO2eels SiFilmSlicePlotXML) 
+set(SerialParallelTests CuBulk CuBulkXML Fe_1l Fe_1lXML Fe-Atom CuBand CuBandXML CuDOS CuDOSXML
+Fe_bct Fe_bctXML PTO PTOXML Fe_1l_SOC Fe_1l_SOCXML PTO-SOC PTO-SOCXML Fe_bct_SOC Fe_bct_SOCXML
+GaAsMultiUForceXML SiFilmSlicePlotXML)
+
+set(SerialOnlyTests Fe_bct_LO Fe_bct_LOXML Fe_fcc Fe_fccXML TiO2eels)
+
+set(Testdirs ${SerialParallelTests} ${SerialOnlyTests})
+set(ParTestdirs ${SerialParallelTests})
 
 #Check if all tests (including those running for a long time) should be executed
 if (all_tests)
     set(Testdirs ${Testdirs} Bi2Te3 Bi2Te3XML NiO_ldau NiO_ldauXML)
+    set(ParTestdirs ${Testdirs} Bi2Te3 Bi2Te3XML NiO_ldau NiO_ldauXML)
 endif()
 
 #Add Wannier tests if fleur is compiled with Wannier support
 if (${FLEUR_USE_WANN})
     set(Testdirs ${Testdirs} Cwann)
+    set(ParTestdirs ${ParTestdirs} Cwann)
 endif()
 
 #The serial tests
@@ -29,7 +35,7 @@ if (${FLEUR_USE_MPI})
    else()
       set(mpi_exec "mpirun -n 2")
    endif()
-   foreach(test ${Testdirs})
+   foreach(test ${ParTestdirs})
     add_test("FLEUR_MPI:${test}" ${CMAKE_CURRENT_SOURCE_DIR}/tests/test.pl
 ${test} "${CMAKE_BINARY_DIR}/fleur_MPI" "${mpi_exec}")
    endforeach(test)