New test for USD import.

Added a basic test for importing a primitive hierarchy from a USDA
file into Blender.  This was reviewed by Sybren in patch D12479.

tests/python/CMakeLists.txt

@@ -838,6 +838,15 @@ if(WITH_ALEMBIC)
   )
 endif()
 
+if(WITH_USD)
+  add_blender_test(
+    usd_import_test
+    --python ${CMAKE_CURRENT_LIST_DIR}/bl_usd_import_test.py
+    --
+    --testdir "${TEST_SRC_DIR}/usd"
+  )
+endif()
+
 if(WITH_CODEC_FFMPEG)
   add_python_test(
     ffmpeg

tests/python/bl_usd_import_test.py

@@ -0,0 +1,78 @@
+# ##### BEGIN GPL LICENSE BLOCK #####
+#
+#  This program is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU General Public License
+#  as published by the Free Software Foundation; either version 2
+#  of the License, or (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program; if not, write to the Free Software Foundation,
+#  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+# ##### END GPL LICENSE BLOCK #####
+
+# <pep8 compliant>
+
+import pathlib
+import sys
+import unittest
+
+import bpy
+
+args = None
+
+class AbstractUSDTest(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        cls.testdir = args.testdir
+
+    def setUp(self):
+        self.assertTrue(self.testdir.exists(),
+                        'Test dir {0} should exist'.format(self.testdir))
+
+        # Make sure we always start with a known-empty file.
+        bpy.ops.wm.open_mainfile(filepath=str(self.testdir / "empty.blend"))
+
+class USDImportTest(AbstractUSDTest):
+
+    def test_import_prim_hierarchy(self):
+        """Test importing a simple object hierarchy from a USDA file."""
+
+        infile = str(self.testdir / "prim-hierarchy.usda")
+
+        res = bpy.ops.wm.usd_import(filepath=infile)
+        self.assertEqual({'FINISHED'}, res)
+
+        objects = bpy.context.scene.collection.objects
+        self.assertEqual(5, len(objects))
+
+        # Test the hierarchy.
+        self.assertIsNone(objects['World'].parent)
+        self.assertEqual(objects['World'], objects['Plane'].parent)
+        self.assertEqual(objects['World'], objects['Plane_001'].parent)
+        self.assertEqual(objects['World'], objects['Empty'].parent)
+        self.assertEqual(objects['Empty'], objects['Plane_002'].parent)
+
+def main():
+    global args
+    import argparse
+
+    if '--' in sys.argv:
+        argv = [sys.argv[0]] + sys.argv[sys.argv.index('--') + 1:]
+    else:
+        argv = sys.argv
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--testdir', required=True, type=pathlib.Path)
+    args, remaining = parser.parse_known_args(argv)
+
+    unittest.main(argv=remaining)
+
+
+if __name__ == "__main__":
+    main()