[TMVA] Disable relevant PyMVA tests if BLAS is not found

This commit makes sure that the tests of PyMVA that require BLAS
(indirectly via SOFIE) are not run when BLAS is not available.

Following up on this PR, which did the same change already for the SOFIE
tests:

#18065
(cherry picked from commit 20d3e3b)

Author: guitargeek

cmake/modules/SearchInstalledSoftware.cmake

@@ -1632,6 +1632,13 @@ if(tmva)
       message(STATUS "TMVA: Numpy or Python development package not found for python ${Python3_EXECUTABLE}. Switching off tmva-pymva option")
       set(tmva-pymva OFF CACHE BOOL "Disabled because Numpy or Python development package were not found (${tmva-pymva_description})" FORCE)
     endif()
+    if(testing)
+      message(STATUS "Looking for BLAS as an optional testing dependency of PyMVA")
+      find_package(BLAS)
+      if(NOT BLAS_FOUND)
+        message(WARNING "BLAS not found: PyMVA will not be fully tested")
+      endif()
+    endif()
   endif()
   if (R_FOUND)
     #Rmva is enable when r is found and tmva is on

tmva/pymva/test/CMakeLists.txt

@@ -83,17 +83,19 @@ if(PY_TORCH_FOUND)
 
    # Test RModelParser_PyTorch
 
-   ROOT_ADD_GTEST(TestRModelParserPyTorch TestRModelParserPyTorch.C
-         LIBRARIES
-         ROOTTMVASofie
-         TMVA
-         Python3::NumPy
-         Python3::Python
-         INCLUDE_DIRS
-         SYSTEM
-         ${CMAKE_CURRENT_BINARY_DIR}
-      )
-   target_link_libraries(TestRModelParserPyTorch ${BLAS_LINKER_FLAGS} ${BLAS_LIBRARIES})
+   if(BLAS_FOUND)
+     ROOT_ADD_GTEST(TestRModelParserPyTorch TestRModelParserPyTorch.C
+           LIBRARIES
+           ROOTTMVASofie
+           TMVA
+           Python3::NumPy
+           Python3::Python
+           BLAS::BLAS
+           INCLUDE_DIRS
+           SYSTEM
+           ${CMAKE_CURRENT_BINARY_DIR}
+        )
+   endif()
 
 endif(PY_TORCH_FOUND)
 
@@ -127,16 +129,18 @@ if((PY_KERAS_FOUND AND PY_THEANO_FOUND) OR (PY_KERAS_FOUND AND PY_TENSORFLOW_FOU
       LIBRARIES ${Libraries})
    ROOT_ADD_TEST(PyMVA-Keras-Multiclass COMMAND testPyKerasMulticlass DEPENDS ${PyMVA-Keras-Multiclass-depends})
 
-   ROOT_ADD_GTEST(TestRModelParserKeras TestRModelParserKeras.C
-    LIBRARIES
-    ROOTTMVASofie
-    PyMVA
-    Python3::NumPy
-    Python3::Python
-    INCLUDE_DIRS
-    SYSTEM
-    ${CMAKE_CURRENT_BINARY_DIR}
-   )
-   target_link_libraries(TestRModelParserKeras ${BLAS_LINKER_FLAGS} ${BLAS_LIBRARIES})
+   if(BLAS_FOUND)
+      ROOT_ADD_GTEST(TestRModelParserKeras TestRModelParserKeras.C
+         LIBRARIES
+         ROOTTMVASofie
+         PyMVA
+         Python3::NumPy
+         Python3::Python
+         BLAS::BLAS
+         INCLUDE_DIRS
+         SYSTEM
+         ${CMAKE_CURRENT_BINARY_DIR}
+     )
+  endif()
 
 endif((PY_KERAS_FOUND AND PY_THEANO_FOUND) OR (PY_KERAS_FOUND AND PY_TENSORFLOW_FOUND))