Add a script to check invalid screenshot(s).

tools/test/util.py

@@ -0,0 +1,31 @@
+#!/usr/bin/env python3
+
+#  Copyright (c) 2024 New Vector Ltd
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+import os
+
+
+def compare(file1, file2):
+    __doc__ = "Compare two files, return True if different, False if identical."
+    # Compare file size
+    file1_stats = os.stat(file1)
+    file2_stats = os.stat(file2)
+    if file1_stats.st_size != file2_stats.st_size:
+        return True
+    # Compare file content
+    with open(file1, "rb") as f1, open(file2, "rb") as f2:
+        content1 = f1.read()
+        content2 = f2.read()
+        return content1 != content2