added csg vs cad volume for **most** stp files

tests/test_volumes.py

@@ -0,0 +1,120 @@
+
+"""
+The tests check the resulting volume of the CSG cells using OpenMC.
+The tests assumes that the test_convert script has previously been run and
+that xml files exist in the tests_outputs folder.
+"""
+import sys
+import math
+import os
+from pathlib import Path
+
+try:
+    import freecad  # importing conda package if present
+except:
+    pass
+import Part
+import pytest
+from FreeCAD import Import
+import openmc
+
+with open("cross_sections.xml", "w") as file:
+    file.write(
+    """
+        <?xml version='1.0' encoding='UTF-8'?>
+        <cross_sections>
+        <library materials="H1" path="" type="neutron"/>
+        </cross_sections>
+    """
+    )
+openmc.config['cross_sections'] = Path("cross_sections.xml").resolve()
+
+path_to_cad = Path("testing/inputSTEP")
+step_files = list(path_to_cad.rglob("*.stp")) + list(path_to_cad.rglob("*.step"))
+
+# this checks if the tests are being run a github action runner or not
+if os.getenv("GITHUB_ACTIONS"):
+    # removing the larger models and models where the volumes don't match from
+    # some of these step file are removed as it fails the volume tests.
+    # Perhaps a bug with torus conversion or a bug with the stp file?
+    # Issue raised https://github.com/GEOUNED-org/GEOUNED/issues/55
+    step_files.remove(Path('testing/inputSTEP/Misc/rails.stp'))
+    step_files.remove(Path('testing/inputSTEP/placa.stp'))
+    step_files.remove(Path('testing/inputSTEP/Misc/tester.stp'))
+    step_files.remove(Path('testing/inputSTEP/large/SCDR.stp'))
+    step_files.remove(Path('testing/inputSTEP/large/Triangle.stp'))
+    step_files.remove(Path('testing/inputSTEP/Torus/face2.stp'))
+    step_files.remove(Path('testing/inputSTEP/Torus/rueda.stp'))
+    # reduced samples as github action runners have 2 threads and more samples
+    # is not needed for the smaller models tested. This allows the CI to
+    # quickly test the smaller models
+    samples=4_000_000
+    rel_tol=0.05
+else:
+    # samples for local run can be larger as threads is likely to be larger
+    samples=400_000_000
+    # acceptable tolerance can also be smaller
+    rel_tol=0.01
+
+
+@pytest.mark.skipif(
+    sys.platform in ["win32", "darwin"],
+    reason="OpenMC doesn't install on Windows currently and is not well tested on Mac"
+)
+@pytest.mark.parametrize(
+    "input_step_file", step_files
+)
+def test_volumes(input_step_file):
+
+    output_dir = Path("tests_outputs") / input_step_file.with_suffix("")
+    output_dir.mkdir(parents=True, exist_ok=True)
+    output_filename_stem = output_dir / input_step_file.stem
+    openmc_xml_file = output_filename_stem.with_suffix(".xml")
+
+    Import.insert(str(input_step_file), "converted-cad")
+    result = Part.Shape()
+    result.read(str(input_step_file))
+
+    materials = openmc.Materials()
+    geometry = openmc.Geometry.from_xml(openmc_xml_file, materials)
+    cells = geometry.get_all_cells()
+
+    # some of the csg cells are void space around the CAD, so we just check
+    # that there are at least as many cells as there could be more cells in the
+    # CSG than the CAD
+    assert len(result.Solids) <= len(cells.keys())
+
+    all_cell_vol_calc = []
+    for solid, (cell_id, cell) in zip(result.Solids, cells.items()):
+
+        bb = solid.BoundBox
+        llx, lly, llz, urx, ury, urz = bb.XMin, bb.YMin, bb.ZMin, bb.XMax, bb.YMax, bb.ZMax
+        llx, lly, llz, urx, ury, urz = llx/10, lly/10, llz/10, urx/10, ury/10, urz/10
+
+        cell_vol_calc = openmc.VolumeCalculation(
+            domains=[cell],
+            samples=samples,
+            lower_left=(llx, lly, llz),
+            upper_right=(urx, ury, urz),
+        )
+        # could add a trigger to ends tests early once they have converged
+        # cell_vol_calc.set_trigger(0.05, 'rel_err')
+
+        all_cell_vol_calc.append(cell_vol_calc)
+
+    settings = openmc.Settings()
+    settings.volume_calculations = all_cell_vol_calc
+    settings.run_mode = "volume"
+    model = openmc.Model(geometry, materials, settings)
+
+    model.export_to_model_xml(path=openmc_xml_file.with_name('model.xml'))
+    openmc.run(cwd=output_dir)
+
+    for solid, (cell_id, cell) in zip(result.Solids, cells.items()):
+
+        vol_calc_file = openmc_xml_file.with_name(f"volume_{cell_id}.h5")
+        cell_vol_calc_results = openmc.VolumeCalculation.from_hdf5(vol_calc_file)
+        volume_of_csg_cell = cell_vol_calc_results.volumes[cell_id].nominal_value
+        # converts from mm3 in cad to cm3 in csg
+        volume_of_cad_cell = solid.Volume * 0.001
+        assert math.isclose(volume_of_cad_cell, volume_of_csg_cell, rel_tol=rel_tol)