Tests: add automated regressions tests for Hydra Storm

These are meant to test Hydra integration. Currently they are only enabled
for WITH_OPENGL_RENDER_TESTS=ON due to similar reasons as Eevee and
Workbench, which is that they require a GPU and results can be platform
dependent due to hardware and driver differences.

There are separate tests for USD and Hydra export paths. The goal is to
make these identical, but they aren't yet. So for that reason they have
separate reference renders, and there is a HTML page to compare them.

Ref #110765

tests/python/CMakeLists.txt

@@ -665,6 +665,33 @@ if(WITH_CYCLES OR WITH_OPENGL_RENDER_TESTS)
           -outdir "${TEST_OUT_DIR}/workbench"
         )
       endforeach()
+
+      if(WITH_HYDRA)
+        # Hydra Storm
+        foreach(render_test ${render_tests})
+          add_python_test(
+            storm_hydra_${render_test}_test
+            ${CMAKE_CURRENT_LIST_DIR}/storm_render_tests.py
+            -blender "${TEST_BLENDER_EXE}"
+            -testdir "${TEST_SRC_DIR}/render/${render_test}"
+            -idiff "${OPENIMAGEIO_IDIFF}"
+            -outdir "${TEST_OUT_DIR}/storm_hydra"
+            -export_method "HYDRA"
+          )
+        endforeach()
+
+        foreach(render_test ${render_tests})
+          add_python_test(
+            storm_usd_${render_test}_test
+            ${CMAKE_CURRENT_LIST_DIR}/storm_render_tests.py
+            -blender "${TEST_BLENDER_EXE}"
+            -testdir "${TEST_SRC_DIR}/render/${render_test}"
+            -idiff "${OPENIMAGEIO_IDIFF}"
+            -outdir "${TEST_OUT_DIR}/storm_usd"
+            -export_method "USD"
+          )
+        endforeach()
+      endif()
     endif()
   endif()
 endif()

tests/python/storm_render_tests.py

@@ -0,0 +1,101 @@
+#!/usr/bin/env python3
+# SPDX-FileCopyrightText: 2015-2023 Blender Foundation
+#
+# SPDX-License-Identifier: Apache-2.0
+
+import argparse
+import os
+import platform
+import shlex
+import shutil
+import subprocess
+import sys
+from pathlib import Path
+
+
+def setup():
+    import bpy
+    import addon_utils
+
+    addon_utils.enable("hydra_storm")
+
+    for scene in bpy.data.scenes:
+        scene.render.engine = 'HYDRA_STORM'
+        scene.hydra.export_method = os.environ['BLENDER_HYDRA_EXPORT_METHOD']
+
+
+# When run from inside Blender, render and exit.
+try:
+    import bpy
+    inside_blender = True
+except ImportError:
+    inside_blender = False
+
+if inside_blender:
+    try:
+        setup()
+    except Exception as e:
+        print(e)
+        sys.exit(1)
+
+
+def get_arguments(filepath, output_filepath):
+    return [
+        "--background",
+        "-noaudio",
+        "--factory-startup",
+        "--enable-autoexec",
+        "--debug-memory",
+        "--debug-exit-on-error",
+        filepath,
+        "-P",
+        os.path.realpath(__file__),
+        "-o", output_filepath,
+        "-F", "PNG",
+        "-f", "1"]
+
+
+def create_argparse():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("-blender", nargs="+")
+    parser.add_argument("-testdir", nargs=1)
+    parser.add_argument("-outdir", nargs=1)
+    parser.add_argument("-idiff", nargs=1)
+    parser.add_argument("-export_method", nargs=1)
+    return parser
+
+
+def main():
+    parser = create_argparse()
+    args = parser.parse_args()
+
+    blender = args.blender[0]
+    test_dir = args.testdir[0]
+    idiff = args.idiff[0]
+    output_dir = args.outdir[0]
+    export_method = args.export_method[0]
+
+    from modules import render_report
+
+    if export_method == 'HYDRA':
+        report = render_report.Report("Storm Hydra", output_dir, idiff)
+        report.set_reference_dir("storm_hydra_renders")
+        report.set_compare_engine('cycles', 'CPU')
+    else:
+        report = render_report.Report("Storm USD", output_dir, idiff)
+        report.set_reference_dir("storm_usd_renders")
+        report.set_compare_engine('hydra_storm')
+
+    report.set_pixelated(True)
+
+    test_dir_name = Path(test_dir).name
+
+    os.environ['BLENDER_HYDRA_EXPORT_METHOD'] = export_method
+
+    ok = report.run(test_dir, blender, get_arguments, batch=True)
+
+    sys.exit(not ok)
+
+
+if not inside_blender and __name__ == "__main__":
+    main()