test(gateway): cover current-turn TTS media dedup

tests/gateway/test_media_extraction.py

@@ -199,6 +199,45 @@ caption
         )
         assert paths == {old_path}
 
+    @pytest.mark.parametrize(
+        "current_path",
+        ["/tmp/tts/current.ogg", "/tmp/tts/already-delivered.ogg"],
+    )
+    def test_non_streaming_dedup_scopes_tts_paths_to_prior_turns(
+        self, current_path
+    ):
+        from gateway.platforms.base import BasePlatformAdapter
+
+        old_path = "/tmp/tts/already-delivered.ogg"
+        transcript = [
+            {"role": "user", "content": "say the old message"},
+            {"role": "assistant", "content": f"MEDIA:{old_path}"},
+            {"role": "user", "content": "say the current message"},
+            {
+                "role": "assistant",
+                "tool_calls": [
+                    {"id": "tts", "function": {"name": "text_to_speech"}}
+                ],
+            },
+            {
+                "role": "tool",
+                "tool_call_id": "tts",
+                "content": f"[[audio_as_voice]]\\nMEDIA:{current_path}",
+            },
+            {
+                "role": "assistant",
+                "content": f"[[audio_as_voice]]\\nMEDIA:{current_path}",
+            },
+        ]
+        adapter = MagicMock()
+        adapter._session_store.peek_session_id.return_value = "session-id"
+        adapter._session_store.load_transcript.return_value = transcript
+
+        paths = BasePlatformAdapter._history_media_paths_for_session(
+            adapter, "session-key"
+        )
+        assert paths == {old_path}
+
     def test_image_generate_not_reemitted_after_compression(self):
         """End-to-end of the #46627 fix: collect history paths, then the
         compression-fallback rescan (history_offset stale) must dedup the