test: add baseline gateway regression suites

Add focused unittest coverage for auth/concurrency, schema normalization, and session-cache tooling behavior, and ignore local .gitnexus index artifacts.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/test_schema_normalization.py

@@ -0,0 +1,73 @@
+from __future__ import annotations
+
+import unittest
+
+from app.anthropic_schema import (
+    AnthropicMessagesRequest,
+    affinity_key_for_anthropic,
+    anthropic_to_internal_messages,
+    flatten_anthropic_content,
+)
+from app.openai_schema import flatten_content
+
+
+class SchemaNormalizationTests(unittest.TestCase):
+    def test_openai_flatten_content_with_multimodal_parts(self) -> None:
+        out = flatten_content(
+            [
+                {"type": "text", "text": "hello"},
+                {"type": "image_url", "image_url": {"url": "x"}},
+                {"type": "input_audio", "input_audio": {"data": "x"}},
+                {"type": "text", "text": "world"},
+            ]
+        )
+        self.assertEqual(out, "hello\n[image]\n[audio]\nworld")
+
+    def test_anthropic_flatten_content_with_tool_blocks(self) -> None:
+        out = flatten_anthropic_content(
+            [
+                {"type": "text", "text": "before"},
+                {"type": "tool_use", "name": "search", "input": {"q": "hi"}},
+                {"type": "tool_result", "content": "ok"},
+            ]
+        )
+        self.assertIn("before", out)
+        self.assertIn("[tool_use]", out)
+        self.assertIn("[tool_result] ok", out)
+
+    def test_anthropic_to_internal_messages_maps_system_and_messages(self) -> None:
+        req = AnthropicMessagesRequest(
+            model="org_auto",
+            max_tokens=64,
+            system="sys",
+            messages=[
+                {"role": "user", "content": "u1"},
+                {"role": "assistant", "content": "a1"},
+            ],
+        )
+        out = anthropic_to_internal_messages(req)
+        self.assertEqual(out[0], {"role": "system", "content": "sys"})
+        self.assertEqual(out[1], {"role": "user", "content": "u1"})
+        self.assertEqual(out[2], {"role": "assistant", "content": "a1"})
+
+    def test_affinity_key_for_anthropic_priority(self) -> None:
+        req_user = AnthropicMessagesRequest(
+            model="org_auto",
+            max_tokens=64,
+            metadata={"user_id": "u-1"},
+            messages=[{"role": "user", "content": "hello"}],
+        )
+        self.assertEqual(affinity_key_for_anthropic(req_user), "u-1")
+
+        req_fallback = AnthropicMessagesRequest(
+            model="org_auto",
+            max_tokens=64,
+            messages=[{"role": "user", "content": "hello"}],
+        )
+        key = affinity_key_for_anthropic(req_fallback)
+        self.assertIsInstance(key, str)
+        self.assertTrue(key.startswith("first:"))
+
+
+if __name__ == "__main__":
+    unittest.main()