test: add tests and changelog entry for class sorting feature

- Add test suite for DISABLE_CLASS_SORTING configuration
- Test default value, environment variable parsing, and case insensitivity
- Update CHANGELOG.md with new feature entry

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

Author: davidnichols-ops

CHANGELOG.md

@@ -8,6 +8,8 @@ All notable changes to this project will be documented in this file.
 
 - Weight upload support for yolo26-sem semantic segmentation models via
   `version.deploy()` and `workspace.deploy_model()`
+- `ROBOFLOW_DISABLE_CLASS_SORTING` environment variable to preserve custom
+  class ordering during YOLO model deployment (opt-in, defaults to false)
 
 ## 1.3.9
 

tests/util/test_class_sorting.py

@@ -0,0 +1,65 @@
+import os
+import sys
+import unittest
+from unittest.mock import patch
+import importlib.util
+
+# Get the path to config.py directly
+config_path = os.path.join(os.path.dirname(os.path.dirname(os.path.dirname(__file__))), 'roboflow', 'config.py')
+
+
+class TestClassSorting(unittest.TestCase):
+    """Test DISABLE_CLASS_SORTING configuration for class ordering."""
+
+    def test_disable_class_sorting_default_value(self):
+        """Test that DISABLE_CLASS_SORTING defaults to False."""
+        # Load config module directly without triggering __init__.py
+        spec = importlib.util.spec_from_file_location("config", config_path)
+        config = importlib.util.module_from_spec(spec)
+        spec.loader.exec_module(config)
+        
+        self.assertFalse(config.DISABLE_CLASS_SORTING)
+
+    def test_disable_class_sorting_env_var_true(self):
+        """Test that ROBOFLOW_DISABLE_CLASS_SORTING=true sets config to True."""
+        with patch.dict(os.environ, {"ROBOFLOW_DISABLE_CLASS_SORTING": "true"}):
+            # Reload config to pick up env var
+            spec = importlib.util.spec_from_file_location("config", config_path)
+            config = importlib.util.module_from_spec(spec)
+            spec.loader.exec_module(config)
+            
+            # After reload, should be True
+            self.assertTrue(config.DISABLE_CLASS_SORTING)
+
+    def test_disable_class_sorting_env_var_false(self):
+        """Test that ROBOFLOW_DISABLE_CLASS_SORTING=false keeps config as False."""
+        with patch.dict(os.environ, {"ROBOFLOW_DISABLE_CLASS_SORTING": "false"}):
+            spec = importlib.util.spec_from_file_location("config", config_path)
+            config = importlib.util.module_from_spec(spec)
+            spec.loader.exec_module(config)
+            
+            self.assertFalse(config.DISABLE_CLASS_SORTING)
+
+    def test_disable_class_sorting_env_var_case_insensitive(self):
+        """Test that env var is case-insensitive."""
+        for value in ["True", "TRUE", "tRuE"]:
+            with patch.dict(os.environ, {"ROBOFLOW_DISABLE_CLASS_SORTING": value}):
+                spec = importlib.util.spec_from_file_location("config", config_path)
+                config = importlib.util.module_from_spec(spec)
+                spec.loader.exec_module(config)
+                
+                self.assertTrue(config.DISABLE_CLASS_SORTING)
+
+    def test_config_import(self):
+        """Test that DISABLE_CLASS_SORTING exists and is a boolean."""
+        spec = importlib.util.spec_from_file_location("config", config_path)
+        config = importlib.util.module_from_spec(spec)
+        spec.loader.exec_module(config)
+        
+        config_value = config.DISABLE_CLASS_SORTING
+        self.assertIsNotNone(config_value)
+        self.assertIsInstance(config_value, bool)
+
+
+if __name__ == "__main__":
+    unittest.main()