allowing geometry to be fully made via constructor (#2602)

Co-authored-by: Paul Romano <[email protected]>

openmc/geometry.py

@@ -39,11 +39,16 @@ class Geometry:
 
     """
 
-    def __init__(self, root=None):
+    def __init__(
+        self,
+        root: typing.Optional[openmc.UniverseBase] = None,
+        merge_surfaces: bool = False,
+        surface_precision: int = 10
+    ):
         self._root_universe = None
         self._offsets = {}
-        self.merge_surfaces = False
-        self.surface_precision = 10
+        self.merge_surfaces = merge_surfaces
+        self.surface_precision = surface_precision
         if root is not None:
             if isinstance(root, openmc.UniverseBase):
                 self.root_universe = root

tests/unit_tests/test_geometry.py

@@ -362,8 +362,13 @@ def get_cyl_cell(r1, r2, z1, z2, fill):
     clad = get_cyl_cell(r1, r2, z1, z2, m2)
     water = get_cyl_cell(r2, r3, z1, z2, m3)
     root = openmc.Universe(cells=[fuel, clad, water])
-    geom = openmc.Geometry(root)
-    geom.merge_surfaces=True
+    geom = openmc.Geometry(root=root, merge_surfaces=True, surface_precision=11)
+    assert geom.merge_surfaces is True
+    geom.merge_surfaces = False
+    assert geom.merge_surfaces is False
+    assert geom.surface_precision == 11
+    geom.surface_precision = 10
+    assert geom.surface_precision == 10
     model = openmc.model.Model(geometry=geom,
                                materials=openmc.Materials([m1, m2, m3]))