[build] Add post-install test for Python bindings

Author: vepadulano

test/PostInstall/CMakeLists.txt

@@ -18,4 +18,22 @@ if(BUILD_TESTING)
     WORKING_DIRECTORY ${CMAKE_BINARY_DIR})
   set_tests_properties(run-hsimple   PROPERTIES FIXTURES_SETUP    HSIMPLE)
   set_tests_properties(read-hsimple  PROPERTIES FIXTURES_REQUIRED HSIMPLE)
+
+  find_package(Python3 3.8 REQUIRED)
+  # Need to duplicate the import ROOT test because the PASS_REGULAR_EXPRESSION
+  # property will disable checking the exit code of the test so import ROOT
+  # might fail but ctest would not report it
+  add_test(NAME python-import-root
+    COMMAND ${Python3_EXECUTABLE} -c "import ROOT"
+  )
+  set_tests_properties(python-import-root
+    PROPERTIES ENVIRONMENT PYTHONPATH=${ROOT_LIBRARY_DIR}
+  )
+  add_test(NAME python-create-histo
+    COMMAND ${Python3_EXECUTABLE} -c "import ROOT; h = ROOT.TH1D(\"myHistoName\",\"h\", 100, -5, 5); print(h.GetName());"
+  )
+  set_tests_properties(python-create-histo
+    PROPERTIES ENVIRONMENT PYTHONPATH=${ROOT_LIBRARY_DIR}
+               PASS_REGULAR_EXPRESSION "myHistoName"
+  )
 endif()