[FEATURE] Static library wrapper around main model + math solver for speeding up tests

[mgovers]

Relates to https://github.com/PowerGridModel/power-grid-model/issues/486

A major factor in the compilation is the fact that all 3 test files of the main model + the validator + the benchmark need to recompile all templates individually. Making a static library wrapper would reduce this to only 1 compilation.

The way to do that is the following:

• [ ] Add a separate library to the tests directory: tests/cpp_test_wrappers/
  • [ ] Add a CMakeLists.txt to expose a STATIC library cpp_test_wrappers
  • [ ] Add a header tests/cpp_test_wrappers/include/cpp_test_wrappers/main_model_wrapper.hpp
    • [ ] declare class:

      class MainModelWrapper {
        private:
          class Impl;
      
        public:
          // all public methods of MainModel
      
        private:
          std::unique_ptr<Impl> impl_;
      }
      

  • [ ] Add a cpp file tests/cpp_wrappers/src/main_model_wrapper.cpp
    • [ ] declare class impl:

      class MainModelWrapper::Impl : public MainModel {
        public:
          using MainModel::MainModelImpl;
      };
      

    • [ ] implement all public methods of MainModelWrapper by forwarding the call to MainModel
    • [ ] Add all static checks from test_main_model_static.cpp to this file
• [ ] Modify test_main_model_*.cpp, the cpp_validation tests and the benchmark to use this library instead of the static MainModel
• [ ] Optionally: Create a separate test executable for test_main_model_* to speed up compilation for people who are developing things upstream and don't care about main model yet
• [ ] Optionally: do the same for the MathModel
  • [ ] Split the MathModel tests into separate files

[TonyXiang8787]

I wonder if we are creating static library anyway, why don't we just make power_grid_model core library itself a static library. We try to compile the header files in several compilation unit.

[mgovers]

I've been thinking about that as well. Let's discuss offline

[mgovers]

As discussed: we will solve this in a different way