chore: import upstream snapshot with attribution

tests/realtime/test_agent.py

@@ -0,0 +1,52 @@
+from __future__ import annotations
+
+from typing import Any
+
+import pytest
+
+from agents import RunContextWrapper
+from agents.realtime.agent import RealtimeAgent
+
+
+def test_can_initialize_realtime_agent():
+    agent = RealtimeAgent(name="test", instructions="Hello")
+    assert agent.name == "test"
+    assert agent.instructions == "Hello"
+
+
+@pytest.mark.asyncio
+async def test_dynamic_instructions():
+    agent = RealtimeAgent(name="test")
+    assert agent.instructions is None
+
+    def _instructions(ctx, agt) -> str:
+        assert ctx.context is None
+        assert agt == agent
+        return "Dynamic"
+
+    agent = RealtimeAgent(name="test", instructions=_instructions)
+    instructions = await agent.get_system_prompt(RunContextWrapper(context=None))
+    assert instructions == "Dynamic"
+
+
+def test_post_init_rejects_invalid_field_types() -> None:
+    with pytest.raises(TypeError, match="RealtimeAgent name must be a string"):
+        RealtimeAgent(name=1)  # type: ignore[arg-type]
+    with pytest.raises(TypeError, match="RealtimeAgent tools must be a list"):
+        RealtimeAgent(name="x", tools="nope")  # type: ignore[arg-type]
+    with pytest.raises(TypeError, match="RealtimeAgent handoffs must be a list"):
+        RealtimeAgent(name="x", handoffs="nope")  # type: ignore[arg-type]
+    with pytest.raises(TypeError, match="RealtimeAgent instructions must be"):
+        RealtimeAgent(name="x", instructions=123)  # type: ignore[arg-type]
+
+
+def test_clone_does_not_mutate_original_lists() -> None:
+    """Cloning with a new list must not affect the original agent's lists."""
+    original = RealtimeAgent(name="orig", tools=[], handoffs=[])
+    new_tools: list[Any] = ["t1"]
+    cloned = original.clone(tools=new_tools)
+    assert original.tools == []
+    assert len(cloned.tools) == 1
+    assert cloned.tools is not original.tools
+    # Shared reference when not overridden (documented shallow-copy behavior).
+    assert cloned.handoffs is original.handoffs