fix: move imports to top level, fix logprobs test schema

logprobs Choice requires top_logprobs field, was missing.
Inline imports in test methods trigger PLC0415 lint error.

Author: ArkaD171717

integrations/openrouter/tests/test_openrouter_chat_generator.py

@@ -22,6 +22,7 @@
 
 from haystack_integrations.components.generators.openrouter.chat.chat_generator import (
     OpenRouterChatGenerator,
+    _convert_openrouter_chunk_to_streaming_chunk,
     _convert_openrouter_completion_to_chat_message,
     _extract_reasoning,
 )
@@ -1410,7 +1411,11 @@ def test_convert_completion_with_logprobs(self):
             choices=[
                 Choice(
                     finish_reason="stop",
-                    logprobs={"content": [{"token": "Hello", "logprob": -0.5}]},
+                    logprobs={
+                        "content": [
+                            {"token": "Hello", "logprob": -0.5, "top_logprobs": [], "bytes": [72, 101, 108, 108, 111]}
+                        ]
+                    },
                     index=0,
                     message=ChatCompletionMessage(content="Hello!", role="assistant"),
                 )
@@ -1458,10 +1463,6 @@ def test_convert_completion_malformed_tool_call_json(self):
         assert result.tool_calls[0].id == "call_good"
 
     def test_convert_chunk_empty_choices(self):
-        from haystack_integrations.components.generators.openrouter.chat.chat_generator import (
-            _convert_openrouter_chunk_to_streaming_chunk,
-        )
-
         chunk = ChatCompletionChunk(
             id="gen-empty",
             choices=[],

integrations/openrouter/tests/test_openrouter_chat_generator_async.py

@@ -10,9 +10,13 @@
     StreamingChunk,
 )
 from haystack.tools import Tool, Toolset
+from haystack.utils.auth import Secret
 from openai import AsyncOpenAI
-from openai.types.chat import ChatCompletion, ChatCompletionMessage
+from openai.types.chat import ChatCompletion, ChatCompletionChunk, ChatCompletionMessage
 from openai.types.chat.chat_completion import Choice
+from openai.types.chat.chat_completion_chunk import Choice as ChoiceChunk
+from openai.types.chat.chat_completion_chunk import ChoiceDelta
+from openai.types.completion_usage import CompletionUsage
 
 from haystack_integrations.components.generators.openrouter.chat.chat_generator import (
     OpenRouterChatGenerator,
@@ -384,12 +388,6 @@ async def test_run_async_empty_messages(self, monkeypatch):
     @pytest.mark.asyncio
     async def test_handle_async_stream_response_with_reasoning(self, monkeypatch):
         monkeypatch.setenv("OPENROUTER_API_KEY", "fake-api-key")
-        from openai.types.chat import ChatCompletionChunk
-        from openai.types.chat.chat_completion_chunk import Choice as ChoiceChunk
-        from openai.types.chat.chat_completion_chunk import ChoiceDelta
-        from openai.types.completion_usage import CompletionUsage
-
-        from haystack.utils.auth import Secret
 
         chunks = [
             ChatCompletionChunk(