SlicerCustomAppTemplate build fails on Loadable Module

Development
1

I have a SlicerCustomApplication with a loadable module with this tree structure:

.
├── CMakeLists.txt
├── Logic
│   ├── CMakeLists.txt
│   ├── vtkKernelFeedMultiply.cxx
│   ├── vtkKernelFeedMultiply.h
│   ├── vtkSlicerFeedMultiplyLogic.cxx
│   └── vtkSlicerFeedMultiplyLogic.h
├── Resources
│   ├── Icons
│   │   └── FeedMultiply.png
│   ├── UI
│   │   ├── qSlicerFeedMultiplyFooBarWidget.ui
│   │   └── qSlicerFeedMultiplyModuleWidget.ui
│   └── qSlicerFeedMultiplyModule.qrc
├── Testing
│   ├── CMakeLists.txt
│   └── Cxx
│       └── CMakeLists.txt
├── Widgets
│   ├── CMakeLists.txt
│   ├── qSlicerFeedMultiplyFooBarWidget.cxx
│   └── qSlicerFeedMultiplyFooBarWidget.h
├── build.sh
├── qSlicerFeedMultiplyModule.cxx
├── qSlicerFeedMultiplyModule.h
├── qSlicerFeedMultiplyModuleWidget.cxx
└── qSlicerFeedMultiplyModuleWidget.h

the customapp always built correctly while this module was bundled in an Extension. Now for development reasons I had to take this out of such extension and add it directly through the cmake Slicer_EXTENSION_SOURCE_DIRS variable in the app CMakeLists.txt.

Now the build fails with:

/opt/p/Slicer-build/E/FeedMultiply/qSlicerFeedMultiplyModuleWidgetGenericTest.cxx:51:10: fatal error: 'qSlicerFeedMultiplyModule.h' file not found
#include "qSlicerFeedMultiplyModule.h"
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
make[2]: *** [E/FeedMultiply/CMakeFiles/qSlicerFeedMultiplyModuleGenericCxxTests.dir/qSlicerFeedMultiplyModuleWidgetGenericTest.cxx.o] Error 1
make[2]: *** Waiting for unfinished jobs....
/opt/p/Slicer-build/E/FeedMultiply/qSlicerFeedMultiplyModuleGenericTest.cxx:49:10: fatal error: 'qSlicerFeedMultiplyModule.h' file not found
#include "qSlicerFeedMultiplyModule.h"
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
make[2]: *** [E/FeedMultiply/CMakeFiles/qSlicerFeedMultiplyModuleGenericCxxTests.dir/qSlicerFeedMultiplyModuleGenericTest.cxx.o] Error 1
make[1]: *** [E/FeedMultiply/CMakeFiles/qSlicerFeedMultiplyModuleGenericCxxTests.dir/all] Error 2
make: *** [all] Error 2

A workaround is commenting the default flag WITH_GENERIC_TESTS in slicerMacroBuildLoadableModule in the module CMakeLists.txt. Then it build correctly

Any suggestion on why this happens?

Thank you very much

2

You can compare your CMakeLists.txt files with similar files in other extensions, such as in SlicerIGT.