From ab644f2ecbf6acf1f8412d4e11e0ff1276085a3d Mon Sep 17 00:00:00 2001
From: Brecht Van Lommel <brecht@blender.org>
Date: Thu, 25 Sep 2025 15:02:13 +0200
Subject: [PATCH] Tests: Compare all subimages in compositor file output tests

For multilayer files it was only comparing the first pass, so any issues
with other passes would be missed.

Also don't clear the filename for multilayer file output nodes, as that
doesn't work when there are multiple such nodes all writing to the same
file name. This will be used in an upcoming EXR multipart writing test.

Ref #146650

Pull Request: https://projects.blender.org/blender/blender/pulls/146726
---
 tests/python/compositor_file_output_tests.py | 76 ++++++++++++--------
 1 file changed, 48 insertions(+), 28 deletions(-)

diff --git a/tests/python/compositor_file_output_tests.py b/tests/python/compositor_file_output_tests.py
index 654cd50efa0..960022e0015 100644
--- a/tests/python/compositor_file_output_tests.py
+++ b/tests/python/compositor_file_output_tests.py
@@ -46,43 +46,60 @@ class FileOutputTest(unittest.TestCase):
         """
         Compare content and metadata of two images.
         """
-        ref_img = oiio.ImageBuf(ref_img_path)
-        out_img = oiio.ImageBuf(out_img_path)
         img_name = os.path.basename(ref_img_path)
 
-        ok = True
-        # Compare image content
-        comp = oiio.ImageBufAlgo.compare(ref_img, out_img, self.fail_threshold, 0)
-        if comp.nfail != 0:
+        ref_input = oiio.ImageInput.open(ref_img_path)
+        out_input = oiio.ImageInput.open(out_img_path)
+
+        # We'll compare all subimages, so that every pass in multilayer, multiview
+        # and multipart EXR files is checked.
+        ref_subimages = ref_input.spec().get_int_attribute("oiio:subimages", 1)
+        out_subimages = out_input.spec().get_int_attribute("oiio:subimages", 1)
+        if ref_subimages != out_subimages:
             if verbose:
-                print_message("Image content mismatch for '{:s}'".format(img_name),
+                print_message("Image subimages mismatch for '{:s}': {} -> {}".
+                              format(img_name, ref_subimages, out_subimages),
                               'FAILURE', 'FAILED')
-            ok = False
+            return False
 
-        # Compare Metadata
-        metadata_ignore = set(("Time", "File", "Date", "RenderTime", "Software"))
+        ok = True
 
-        ref_meta = ref_img.spec().extra_attribs
-        out_meta = out_img.spec().extra_attribs
+        for subimage in range(0, ref_subimages):
+            ref_img = oiio.ImageBuf(ref_img_path, subimage, 0, oiio.ImageSpec())
+            out_img = oiio.ImageBuf(out_img_path, subimage, 0, oiio.ImageSpec())
 
-        for attrib in ref_meta:
-            if attrib.name in metadata_ignore:
-                continue
-            if attrib.name not in out_meta:
+            # Compare image content
+            comp = oiio.ImageBufAlgo.compare(ref_img, out_img, self.fail_threshold, 0)
+            if comp.nfail != 0:
                 if verbose:
-                    print_message(
-                        "Image metadata mismatch: metadata '{:s}' does not exist in output image '{:s}'".format(
-                            attrib.name, img_name), 'FAILURE', 'FAILED')
-                ok = False
-                continue
-            if attrib.value != out_meta[attrib.name]:
-                if verbose:
-                    print_message(
-                        "Image metadata mismatch for metadata '{:s}' in image '{:s}'".format(attrib.name, img_name),
-                        'FAILURE',
-                        'FAILED')
+                    print_message("Image content mismatch for '{:s}'".format(img_name),
+                                  'FAILURE', 'FAILED')
                 ok = False
 
+            # Compare Metadata
+            metadata_ignore = set(("Time", "File", "Date", "RenderTime", "Software"))
+
+            ref_meta = ref_img.spec().extra_attribs
+            out_meta = out_img.spec().extra_attribs
+
+            for attrib in ref_meta:
+                if attrib.name in metadata_ignore:
+                    continue
+                if attrib.name not in out_meta:
+                    if verbose:
+                        print_message(
+                            "Image metadata mismatch: metadata '{:s}' does not exist in output image '{:s}'".format(
+                                attrib.name, img_name), 'FAILURE', 'FAILED')
+                    ok = False
+                    continue
+                if attrib.value != out_meta[attrib.name]:
+                    if verbose:
+                        print_message(
+                            "Image metadata mismatch for metadata '{:s}' in image '{:s}'".format(attrib.name, img_name),
+                            'FAILURE',
+                            'FAILED')
+                    ok = False
+
         return ok
 
     def update_tests(self, testdir, outdir):
@@ -201,7 +218,10 @@ class FileOutputTest(unittest.TestCase):
             for node in node_tree.nodes:
                 if node.type == 'OUTPUT_FILE':
                     node.directory = f'{curr_out_dir}/'
-                    node.file_name = ""
+                    # Can't use empty filename for multilayer, as multiple such
+                    # nodes will write to the same file name then.
+                    if node.format.media_type != 'MULTI_LAYER_IMAGE':
+                        node.file_name = ""
                 elif node.type == 'GROUP' and node.node_tree:
                     set_directory(node.node_tree, base_path)