[test] guard python install tests, run only if pyroot found

as suggested by guitargeek

Author: ferdymercury

test/PostInstall/CMakeLists.txt

@@ -18,22 +18,23 @@ 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 3.9 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"
-  )
+  if(ROOT_pyroot_FOUND)
+    find_package(Python3 3.9 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()
 endif()