Bugfix/overhaul dune python add test

The changes on this MR overhaul the dune_python_add_test command. There was some functionality missing that could not have been added easily, so I decided to rewrite some parts of it. Now it forwards to dune_add_test and therefore uses some functionality from there, e.g. CMAKE_GUARDS, MPI_RANKS, etc.

I tested with some core modules, but this should be also tested by some of you for different setups, use-cases and custom modules.

cmake/modules/DunePythonTestCommand.cmake

@@ -2,6 +2,18 @@
 #
 # .. cmake_function:: dune_python_add_test
 #
+#    .. cmake_brief::
+#
+#       Integrates a python testing framework command into the Dune
+#       build system. Added commands are run, when the target
+#       :code:`test_python` is built and during :code:`ctest`.
+#
+#    .. cmake_param:: NAME
+#       :single:
+#
+#       A name to identify this test in ctest. Names must be unique throughout
+#       the project. If omitted, defaults to mangling of the command.
+#
 #    .. cmake_param:: SCRIPT
 #       :multi:
 #
@@ -16,14 +28,21 @@
 #    .. cmake_param:: MODULE
 #       :multi:
 #
-#       The Python module to be executed.  It will be executed during :code:`make test_python`
-#       and during `ctest`. You are required to either pass SCRIPT or MODULE.
+#       The Python module to be executed. It will be executed during :code:`make test_python`
+#       and during `ctest`.
+#
+#       You are required to either pass SCRIPT or MODULE.
 #
 #       .. note::
 #
 #          The script will be executed using :code:`${Python3_EXECUTABLE} -m MODULE`. If the INTERPRETER
 #          option is given, that interpreter is used instead.
 #
+#    .. cmake_param:: INTERPRETER
+#       :single:
+#
+#       The Python interpreter to be used. Defaults to :code:`${DUNE_PYTHON_VIRTUALENV_EXECUTABLE}`.
+#
 #    .. cmake_param:: WORKING_DIRECTORY
 #       :single:
 #       :argname: dir
@@ -31,23 +50,52 @@
 #       The working directory of the command. Defaults to
 #       the current build directory.
 #
-#    .. cmake_param:: NAME
-#       :single:
+#    .. cmake_param:: LABELS
+#       :multi:
 #
-#       A name to identify this test in ctest. Names must be unique throughout
-#       the project. If omitted, defaults to mangling of the command.
+#       A list of labels to add to the test.
+#
+#    .. cmake_param:: CMAKE_GUARD
+#       :multi:
+#       :argname: condition
+#
+#       A number of conditions that CMake should evaluate before adding this
+#       test. If one of the conditions fails, the test should be shown
+#       as skipped in the test summary. Use this feature instead of guarding
+#       the call to :code:`dune_add_test` with an :code:`if` clause.
+#
+#       The passed condition can be a complex expression like
+#       `( A OR B ) AND ( C OR D )`. Mind the spaces around the parentheses.
+#
+#       Example: Write CMAKE_GUARD dune-foo_FOUND if you want your test to only
+#       build and run when the dune-foo module is present.
+#
+#    .. cmake_param:: MPI_RANKS
+#       :multi:
+#       :argname: ranks
+#
+#       The numbers of cores that this test should be executed with.
+#       Note that one test (in the ctest sense) is created for each number
+#       given here. Any number exceeding the user-specified processor maximum
+#       :ref:`DUNE_MAX_TEST_CORES` will be ignored. Tests with a
+#       processor number :code:`n` higher than one will have the suffix
+#       :code:`-mpi-n` appended to their name. You need to specify the
+#       TIMEOUT option when specifying the MPI_RANKS option.
+#
+#    .. cmake_param:: TIMEOUT
+#       :single:
 #
-#    Integrates a python testing framework command into the Dune
-#    build system. Added commands are run, when the target
-#    :code:`test_python` is built and during :code:`ctest`.
+#       If set, the test will time out after the given number of seconds. This supersedes
+#       any timeout setting in ctest (see `cmake --help-property TIMEOUT`). If you
+#       specify the MPI_RANKS option, you need to specify a TIMEOUT.
 #
 include_guard(GLOBAL)
 
 function(dune_python_add_test)
   # Parse Arguments
   set(OPTION)
-  set(SINGLE WORKING_DIRECTORY NAME)
-  set(MULTI SCRIPT COMMAND LABELS MODULE)
+  set(SINGLE NAME WORKING_DIRECTORY INTERPRETER)
+  set(MULTI SCRIPT MODULE COMMAND LABELS CMAKE_GUARD MPI_RANKS TIMEOUT)
   cmake_parse_arguments(PYTEST "" "${SINGLE}" "${MULTI}" ${ARGN})
   if(PYTEST_COMMAND)
     message(FATAL_ERROR "dune_python_add_test: COMMAND argument should not be used, use SCRIPT instead providing only the Python script and not the Python interpreter")
@@ -77,33 +125,23 @@ function(dune_python_add_test)
     set(commandstr "${commandstr}_${PYTEST_WORKING_DIRECTORY}")
     string(REPLACE "/" "_" PYTEST_NAME ${commandstr})
   endif()
-
-  if(DUNE_PYTHON_VENVSETUP)
-    # Actually run the command
-    add_custom_target(target_${PYTEST_NAME}
-                      COMMAND ${CMAKE_BINARY_DIR}/run-in-dune-env python ${PYTEST_SCRIPT}
-                      WORKING_DIRECTORY ${PYTEST_WORKING_DIRECTORY})
-  else()
-    # message(FATAL_ERROR "SHOULDN'T BE HERE")
-    # add_custom_target(target_${PYTEST_NAME}
-    #                   COMMAND ${CMAKE_COMMAND} -E echo \"Test not run: python setup failed\")
-    add_custom_target(target_${PYTEST_NAME}
-                      COMMAND ${CMAKE_BINARY_DIR}/run-in-dune-env python ${PYTEST_SCRIPT}
-                      WORKING_DIRECTORY ${PYTEST_WORKING_DIRECTORY})
+  if(NOT PYTEST_INTERPRETER)
+    set(PYTEST_INTERPRETER ${DUNE_PYTHON_VIRTUALENV_EXECUTABLE})
   endif()
 
+  add_custom_target(target_${PYTEST_NAME})
+  dune_add_test(NAME ${PYTEST_NAME}
+                TARGET target_${PYTEST_NAME}
+                COMMAND ${PYTEST_INTERPRETER}
+                CMD_ARGS ${PYTEST_SCRIPT}
+                PYTHON_TEST
+                WORKING_DIRECTORY ${PYTEST_WORKING_DIRECTORY}
+                LABELS ${PYTEST_LABELS}
+                CMAKE_GUARD ${PYTEST_CMAKE_GUARD}
+                MPI_RANKS ${PYTEST_MPI_RANKS}
+                TIMEOUT ${PYTEST_TIMEOUT}
+                )
+
   # Build this during make test_python
   add_dependencies(test_python target_${PYTEST_NAME})
-
-  # make sure each label exists and its name is acceptable
-  dune_declare_test_label(LABELS ${PYTEST_LABELS})
-
-  # Also build this during ctest
-  _add_test(NAME ${PYTEST_NAME}
-            COMMAND ${CMAKE_BINARY_DIR}/run-in-dune-env python ${PYTEST_SCRIPT}
-            WORKING_DIRECTORY ${PYTEST_WORKING_DIRECTORY}
-            )
-  set_tests_properties(${PYTEST_NAME} PROPERTIES SKIP_RETURN_CODE 77)
-  # Set the labels on the test
-  set_tests_properties(${PYTEST_NAME} PROPERTIES LABELS "${PYTEST_LABELS}")
 endfunction()