xz-provider 0.5.0

LLM 服务提供者抽象层 — 统一的 LLM 服务提供者接口
Documentation
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1338
    use super::*;
    use std::collections::HashMap;

    use crate::types::{
        ContentPart, FinishReason, Message, MessageContent, ReasoningEffort, ResponseFormat,
        ServiceTier, ThinkingConfig, ThinkingType, TokenUsage, ToolChoice, ToolDefinition,
    };

    // ── build_request_body tests ──

    #[test]
    fn test_build_request_body_basic() {
        let adapter = OpenAiChatAdapter::new();
        let request = CompletionRequest::new("gpt-4o", vec![Message::user("Hello")]);
        let body = adapter.build_request_body(&request, false).unwrap();

        assert_eq!(body["model"], "gpt-4o");
        assert_eq!(body["stream"], false);
        assert!(body["messages"].is_array());
        assert_eq!(body["messages"][0]["role"], "user");
        assert_eq!(body["messages"][0]["content"], "Hello");
    }

    #[test]
    fn test_build_request_body_default_model() {
        let adapter = OpenAiChatAdapter::new();
        let request = CompletionRequest {
            model: None,
            messages: vec![Message::user("Hi")],
            ..Default::default()
        };
        let body = adapter.build_request_body(&request, false).unwrap();
        assert_eq!(body["model"], "gpt-4o");
    }

    #[test]
    fn test_build_request_body_streaming() {
        let adapter = OpenAiChatAdapter::new();
        let request = CompletionRequest::new("gpt-4o", vec![Message::user("Hello")]);
        let body = adapter.build_request_body(&request, true).unwrap();
        assert_eq!(body["stream"], true);
    }

    #[test]
    fn test_build_request_body_with_all_options() {
        let adapter = OpenAiChatAdapter::new();
        let mut request = CompletionRequest::new("gpt-4o", vec![Message::user("Hello")]);
        request.temperature = Some(0.5);
        request.max_tokens = Some(100);
        request.max_completion_tokens = Some(200);
        request.top_p = Some(0.5);
        request.top_k = Some(50);
        request.frequency_penalty = Some(0.5);
        request.presence_penalty = Some(0.5);
        request.seed = Some(42);
        request.reasoning_effort = Some(ReasoningEffort::Medium);
        request.logprobs = Some(true);
        request.stop = Some(vec!["\n".into(), "END".into()]);
        request.stream_include_usage = Some(true);

        let body = adapter.build_request_body(&request, true).unwrap();
        assert_eq!(body["temperature"], 0.5);
        assert_eq!(body["max_tokens"], 100);
        assert_eq!(body["max_completion_tokens"], 200);
        assert_eq!(body["top_p"], 0.5);
        assert_eq!(body["top_k"], 50);
        assert_eq!(body["frequency_penalty"], 0.5);
        assert_eq!(body["presence_penalty"], 0.5);
        assert_eq!(body["seed"], 42);
        assert_eq!(body["reasoning_effort"], "medium");
        assert_eq!(body["logprobs"], true);
        assert_eq!(body["stop"], serde_json::json!(["\n", "END"]));
        assert_eq!(body["stream_options"]["include_usage"], true);

        // Non-stream must NOT emit stream_options (DeepSeek 400 otherwise).
        let body_no_stream = adapter.build_request_body(&request, false).unwrap();
        assert!(
            body_no_stream.get("stream_options").is_none(),
            "stream_options must be omitted when stream=false, got {body_no_stream}"
        );
    }

    #[test]
    fn test_stream_options_only_when_streaming() {
        let adapter = OpenAiChatAdapter::new();
        let mut request = CompletionRequest::new("deepseek-v4-pro", vec![Message::user("Hello")]);
        request.stream_include_usage = Some(true);

        let streamed = adapter.build_request_body(&request, true).unwrap();
        assert_eq!(streamed["stream"], true);
        assert_eq!(streamed["stream_options"]["include_usage"], true);

        let non_stream = adapter.build_request_body(&request, false).unwrap();
        assert_eq!(non_stream["stream"], false);
        assert!(
            non_stream.get("stream_options").is_none(),
            "DeepSeek rejects stream_options without stream=true"
        );
    }

    #[test]
    fn test_build_request_body_with_tools() {
        let adapter = OpenAiChatAdapter::new();
        let mut request = CompletionRequest::new("gpt-4o", vec![Message::user("Search?")]);
        request.tools = Some(vec![ToolDefinition {
            name: "search".into(),
            description: "Search the web".into(),
            parameters: serde_json::json!({"type": "object", "properties": {}}),
            strict: None,
        }]);
        request.tool_choice = Some(ToolChoice::Auto);

        let body = adapter.build_request_body(&request, false).unwrap();
        assert!(body["tools"].is_array());
        assert_eq!(body["tools"][0]["type"], "function");
        assert_eq!(body["tools"][0]["function"]["name"], "search");
        assert_eq!(body["tool_choice"], "auto");
    }

    #[test]
    fn test_build_request_body_with_response_format() {
        let adapter = OpenAiChatAdapter::new();
        let mut request = CompletionRequest::new("gpt-4o", vec![Message::user("JSON pls")]);
        request.response_format = Some(ResponseFormat::Json);

        let body = adapter.build_request_body(&request, false).unwrap();
        assert_eq!(body["response_format"]["type"], "json_object");
    }

    #[test]
    fn test_build_request_body_with_multipart_vision() {
        let adapter = OpenAiChatAdapter::new();
        let parts = vec![
            ContentPart::Text { text: "What's in this image?".into() },
            ContentPart::ImageUrl { url: "https://example.com/img.png".into(), detail: None },
        ];
        let request = CompletionRequest::new(
            "gpt-4o",
            vec![Message::User { content: MessageContent::MultiPart(parts) }],
        );
        let body = adapter.build_request_body(&request, false).unwrap();
        let msg = &body["messages"][0];
        assert_eq!(msg["role"], "user");
        assert!(msg["content"].is_array());
        assert_eq!(msg["content"][0]["type"], "text");
        assert_eq!(msg["content"][0]["text"], "What's in this image?");
        assert_eq!(msg["content"][1]["type"], "image_url");
        assert_eq!(msg["content"][1]["image_url"]["url"], "https://example.com/img.png");
    }

    // ── build_auth_headers tests ──

    #[test]
    fn test_build_auth_headers_bearer() {
        let adapter = OpenAiChatAdapter::new();
        let auth = AuthMethod::Bearer { token: "sk-test".into() };
        let headers = adapter.build_auth_headers(&auth);
        assert_eq!(headers.len(), 1);
        assert_eq!(headers[0], ("Authorization".into(), "Bearer sk-test".into()));
    }

    #[test]
    fn test_build_auth_headers_api_key() {
        let adapter = OpenAiChatAdapter::new();
        let auth = AuthMethod::ApiKey { header_name: "x-api-key".into(), key: "my-key".into() };
        let headers = adapter.build_auth_headers(&auth);
        assert_eq!(headers.len(), 1);
        assert_eq!(headers[0], ("x-api-key".into(), "my-key".into()));
    }

    #[test]
    fn test_build_auth_headers_none() {
        let adapter = OpenAiChatAdapter::new();
        let headers = adapter.build_auth_headers(&AuthMethod::None);
        assert!(headers.is_empty());
    }

    // ── parse_response tests ──

    #[test]
    fn test_parse_response_basic() {
        let adapter = OpenAiChatAdapter::new();
        let json = serde_json::json!({
            "id": "chatcmpl-123",
            "object": "chat.completion",
            "created": 1234567890,
            "model": "gpt-4o",
            "choices": [{
                "index": 0,
                "message": {
                    "role": "assistant",
                    "content": "Hello!"
                },
                "finish_reason": "stop"
            }],
            "usage": {
                "prompt_tokens": 10,
                "completion_tokens": 20,
                "total_tokens": 30
            }
        });

        let resp = adapter.parse_response(&json).unwrap();
        assert_eq!(resp.content.as_deref(), Some("Hello!"));
        assert_eq!(resp.model, "gpt-4o");
        assert_eq!(resp.finish_reason, FinishReason::Stop);
        assert_eq!(resp.usage.prompt_tokens, 10);
        assert_eq!(resp.usage.completion_tokens, 20);
        assert_eq!(resp.usage.total_tokens, 30);
        assert!(resp.tool_calls.is_empty());
        assert!(resp.thinking.is_none());
        assert_eq!(resp.id.as_deref(), Some("chatcmpl-123"));
        assert_eq!(resp.created, Some(1234567890));
    }

    #[test]
    fn test_parse_response_with_tool_calls() {
        let adapter = OpenAiChatAdapter::new();
        let json = serde_json::json!({
            "id": "chatcmpl-456",
            "object": "chat.completion",
            "created": 1234567890,
            "model": "gpt-4o",
            "choices": [{
                "index": 0,
                "message": {
                    "role": "assistant",
                    "content": null,
                    "tool_calls": [{
                        "id": "call_abc",
                        "type": "function",
                        "function": {
                            "name": "search",
                            "arguments": "{\"query\": \"hello\"}"
                        }
                    }]
                },
                "finish_reason": "tool_calls"
            }],
            "usage": {
                "prompt_tokens": 10,
                "completion_tokens": 5,
                "total_tokens": 15
            }
        });

        let resp = adapter.parse_response(&json).unwrap();
        assert!(resp.content.is_none());
        assert_eq!(resp.finish_reason, FinishReason::ToolCall);
        assert_eq!(resp.tool_calls.len(), 1);
        assert_eq!(resp.tool_calls[0].id, "call_abc");
        assert_eq!(resp.tool_calls[0].function_name, "search");
        assert_eq!(resp.tool_calls[0].arguments["query"], "hello");
    }

    #[test]
    fn test_parse_response_length_finish() {
        let adapter = OpenAiChatAdapter::new();
        let json = serde_json::json!({
            "id": "chatcmpl-789",
            "object": "chat.completion",
            "model": "gpt-4o",
            "choices": [{
                "index": 0,
                "message": { "role": "assistant", "content": "Partial" },
                "finish_reason": "length"
            }],
            "usage": { "prompt_tokens": 5, "completion_tokens": 100, "total_tokens": 105 }
        });

        let resp = adapter.parse_response(&json).unwrap();
        assert_eq!(resp.finish_reason, FinishReason::MaxTokens);
        assert_eq!(resp.content.as_deref(), Some("Partial"));
    }

    #[test]
    fn test_parse_response_content_filter() {
        let adapter = OpenAiChatAdapter::new();
        let json = serde_json::json!({
            "id": "chatcmpl-xxx",
            "object": "chat.completion",
            "model": "gpt-4o",
            "choices": [{
                "index": 0,
                "message": { "role": "assistant", "content": null },
                "finish_reason": "content_filter"
            }],
            "usage": { "prompt_tokens": 5, "completion_tokens": 0, "total_tokens": 5 }
        });

        let resp = adapter.parse_response(&json).unwrap();
        assert_eq!(resp.finish_reason, FinishReason::ContentFilter);
    }

    #[test]
    fn test_parse_response_unknown_finish_reason_degrades_to_stop() {
        let adapter = OpenAiChatAdapter::new();
        let json = serde_json::json!({
            "id": "chatcmpl-xxx",
            "object": "chat.completion",
            "model": "gpt-4o",
            "choices": [{
                "index": 0,
                "message": { "role": "assistant", "content": "Hi" },
                "finish_reason": "eos"
            }],
            "usage": { "prompt_tokens": 1, "completion_tokens": 1, "total_tokens": 2 }
        });

        let resp = adapter.parse_response(&json).unwrap();
        assert_eq!(resp.finish_reason, FinishReason::Stop);
    }

    #[test]
    fn test_parse_response_missing_finish_reason_defaults_to_stop() {
        let adapter = OpenAiChatAdapter::new();
        let json = serde_json::json!({
            "id": "chatcmpl-xxx",
            "object": "chat.completion",
            "model": "gpt-4o",
            "choices": [{
                "index": 0,
                "message": { "role": "assistant", "content": "Hi" }
            }],
            "usage": { "prompt_tokens": 1, "completion_tokens": 1, "total_tokens": 2 }
        });

        let resp = adapter.parse_response(&json).unwrap();
        assert_eq!(resp.finish_reason, FinishReason::Stop);
    }

    #[test]
    fn test_parse_response_missing_choices_error() {
        let adapter = OpenAiChatAdapter::new();
        let json = serde_json::json!({
            "id": "chatcmpl-xxx",
            "object": "chat.completion",
            "model": "gpt-4o"
        });

        let err = adapter.parse_response(&json).unwrap_err();
        assert!(matches!(err, ProviderError::Format(_)));
        assert!(err.to_string().contains("choices[0]"));
    }

    #[test]
    fn test_parse_response_missing_message_error() {
        let adapter = OpenAiChatAdapter::new();
        let json = serde_json::json!({
            "id": "chatcmpl-xxx",
            "object": "chat.completion",
            "model": "gpt-4o",
            "choices": [{
                "index": 0,
                "finish_reason": "stop"
            }],
            "usage": { "prompt_tokens": 0, "completion_tokens": 0, "total_tokens": 0 }
        });

        let err = adapter.parse_response(&json).unwrap_err();
        assert!(matches!(err, ProviderError::Format(_)));
        assert!(err.to_string().contains("message"));
    }

    #[test]
    fn test_parse_response_with_cached_tokens() {
        let adapter = OpenAiChatAdapter::new();
        let json = serde_json::json!({
            "id": "chatcmpl-xxx",
            "object": "chat.completion",
            "model": "gpt-4o",
            "choices": [{
                "index": 0,
                "message": { "role": "assistant", "content": "Hi" },
                "finish_reason": "stop"
            }],
            "usage": {
                "prompt_tokens": 100,
                "completion_tokens": 50,
                "total_tokens": 150,
                "prompt_tokens_details": {
                    "cached_tokens": 30
                }
            }
        });

        let resp = adapter.parse_response(&json).unwrap();
        assert_eq!(resp.usage.cached_tokens, Some(30));
    }

    #[test]
    fn test_parse_response_no_usage_defaults_to_zero() {
        let adapter = OpenAiChatAdapter::new();
        let json = serde_json::json!({
            "id": "chatcmpl-xxx",
            "object": "chat.completion",
            "model": "gpt-4o",
            "choices": [{
                "index": 0,
                "message": { "role": "assistant", "content": "Hi" },
                "finish_reason": "stop"
            }]
        });

        let resp = adapter.parse_response(&json).unwrap();
        assert_eq!(resp.usage.prompt_tokens, 0);
        assert_eq!(resp.usage.completion_tokens, 0);
        assert_eq!(resp.usage.total_tokens, 0);
    }

    // ── parse_sse_event tests ──

    #[test]
    fn test_parse_sse_content_delta() {
        let adapter = OpenAiChatAdapter::new();
        let data = r#"{"id":"chatcmpl-123","object":"chat.completion.chunk","choices":[{"index":0,"delta":{"content":"Hello"},"finish_reason":null}]}"#;
        let event = adapter.parse_sse_event(data).unwrap();
        assert_eq!(event, Some(StreamEvent::ContentDelta { delta: "Hello".into() }));
    }

    #[test]
    fn test_parse_sse_multiple_content_deltas() {
        let adapter = OpenAiChatAdapter::new();
        let data1 = r#"{"choices":[{"index":0,"delta":{"content":"Hello"},"finish_reason":null}]}"#;
        let data2 =
            r#"{"choices":[{"index":0,"delta":{"content":" World"},"finish_reason":null}]}"#;
        assert_eq!(
            adapter.parse_sse_event(data1).unwrap(),
            Some(StreamEvent::ContentDelta { delta: "Hello".into() })
        );
        assert_eq!(
            adapter.parse_sse_event(data2).unwrap(),
            Some(StreamEvent::ContentDelta { delta: " World".into() })
        );
    }

    #[test]
    fn test_parse_sse_empty_content_ignored() {
        let adapter = OpenAiChatAdapter::new();
        let data = r#"{"choices":[{"index":0,"delta":{"content":""},"finish_reason":null}]}"#;
        let event = adapter.parse_sse_event(data).unwrap();
        assert!(event.is_none());
    }

    #[test]
    fn test_parse_sse_tool_call_delta_with_id_and_name() {
        let adapter = OpenAiChatAdapter::new();
        let data = r#"{"choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"id":"call_abc","type":"function","function":{"name":"search","arguments":""}}]},"finish_reason":null}]}"#;
        let event = adapter.parse_sse_event(data).unwrap();
        assert_eq!(
            event,
            Some(StreamEvent::ToolCallDelta {
                index: 0,
                id: Some("call_abc".into()),
                function_name: Some("search".into()),
                arguments_delta: "".into(),
            })
        );
    }

    #[test]
    fn test_parse_sse_tool_call_delta_arguments_only() {
        let adapter = OpenAiChatAdapter::new();
        let data = r#"{"choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"{\"query\":"}}]},"finish_reason":null}]}"#;
        let event = adapter.parse_sse_event(data).unwrap();
        assert_eq!(
            event,
            Some(StreamEvent::ToolCallDelta {
                index: 0,
                id: None,
                function_name: None,
                arguments_delta: "{\"query\":".into(),
            })
        );
    }

    #[test]
    fn test_parse_sse_finish_reason_emits_done() {
        let adapter = OpenAiChatAdapter::new();
        let data = r#"{"id":"chatcmpl-123","object":"chat.completion.chunk","choices":[{"index":0,"delta":{},"finish_reason":"stop"}],"usage":{"prompt_tokens":10,"completion_tokens":5,"total_tokens":15}}"#;
        let event = adapter.parse_sse_event(data).unwrap();
        assert_eq!(
            event,
            Some(StreamEvent::Done {
                finish_reason: FinishReason::Stop,
                usage: Some(TokenUsage::new(10, 5)),
            })
        );
    }

    #[test]
    fn test_parse_sse_finish_reason_without_usage() {
        let adapter = OpenAiChatAdapter::new();
        let data = r#"{"choices":[{"index":0,"delta":{},"finish_reason":"tool_calls"}]}"#;
        let event = adapter.parse_sse_event(data).unwrap();
        assert_eq!(
            event,
            Some(StreamEvent::Done { finish_reason: FinishReason::ToolCall, usage: None })
        );
    }

    #[test]
    fn test_parse_sse_finish_reason_length() {
        let adapter = OpenAiChatAdapter::new();
        let data = r#"{"choices":[{"index":0,"delta":{},"finish_reason":"length"}]}"#;
        let event = adapter.parse_sse_event(data).unwrap();
        assert_eq!(
            event,
            Some(StreamEvent::Done { finish_reason: FinishReason::MaxTokens, usage: None })
        );
    }

    #[test]
    fn test_parse_sse_finish_reason_content_filter() {
        let adapter = OpenAiChatAdapter::new();
        let data = r#"{"choices":[{"index":0,"delta":{},"finish_reason":"content_filter"}]}"#;
        let event = adapter.parse_sse_event(data).unwrap();
        assert_eq!(
            event,
            Some(StreamEvent::Done { finish_reason: FinishReason::ContentFilter, usage: None })
        );
    }

    #[test]
    fn test_parse_sse_unknown_finish_reason_degrades_to_stop() {
        let adapter = OpenAiChatAdapter::new();
        let data = r#"{"choices":[{"index":0,"delta":{},"finish_reason":"eos"}]}"#;
        let event = adapter.parse_sse_event(data).unwrap();
        assert_eq!(
            event,
            Some(StreamEvent::Done { finish_reason: FinishReason::Stop, usage: None })
        );
    }

    #[test]
    fn test_parse_sse_done_signal_ignored() {
        let adapter = OpenAiChatAdapter::new();
        // [DONE] should be ignored — Done event comes from finish_reason chunk
        let event = adapter.parse_sse_event("[DONE]").unwrap();
        assert!(event.is_none());
    }

    #[test]
    fn test_parse_sse_standalone_usage_event() {
        let adapter = OpenAiChatAdapter::new();
        let data = r#"{"id":"chatcmpl-123","object":"chat.completion.chunk","choices":[],"usage":{"prompt_tokens":10,"completion_tokens":5,"total_tokens":15}}"#;
        let event = adapter.parse_sse_event(data).unwrap();
        assert_eq!(event, Some(StreamEvent::Usage { usage: TokenUsage::new(10, 5) }));
    }

    #[test]
    fn test_parse_sse_invalid_json_returns_error() {
        let adapter = OpenAiChatAdapter::new();
        let result = adapter.parse_sse_event("not valid json");
        assert!(result.is_err());
        assert!(matches!(result.unwrap_err(), ProviderError::Format(_)));
    }

    #[test]
    fn test_parse_sse_empty_event_ignored() {
        let adapter = OpenAiChatAdapter::new();
        // Delta with no content, no tool_calls, no finish_reason
        let data = r#"{"choices":[{"index":0,"delta":{},"finish_reason":null}]}"#;
        let event = adapter.parse_sse_event(data).unwrap();
        assert!(event.is_none());
    }

    #[test]
    fn test_parse_sse_whitespace_only_content_ignored() {
        let adapter = OpenAiChatAdapter::new();
        // Some providers send whitespace in content; should be ignored
        let data = r#"{"choices":[{"index":0,"delta":{"content":" "},"finish_reason":null}]}"#;
        let event = adapter.parse_sse_event(data).unwrap();
        // Content " " is not empty, so it IS emitted
        assert_eq!(event, Some(StreamEvent::ContentDelta { delta: " ".into() }));
    }

    // ── Full streaming workflow tests ──

    /// Test that a complete streaming sequence produces exactly one Done event.
    #[test]
    fn test_full_streaming_sequence_exactly_one_done() {
        let adapter = OpenAiChatAdapter::new();

        let chunks = vec![
            r#"{"choices":[{"index":0,"delta":{"content":"Hello"},"finish_reason":null}]}"#,
            r#"{"choices":[{"index":0,"delta":{"content":" World"},"finish_reason":null}]}"#,
            r#"{"choices":[{"index":0,"delta":{},"finish_reason":"stop"}],"usage":{"prompt_tokens":5,"completion_tokens":3,"total_tokens":8}}"#,
            "[DONE]",
        ];

        let mut events: Vec<StreamEvent> = Vec::new();
        for chunk in &chunks {
            if let Some(event) = adapter.parse_sse_event(chunk).unwrap() {
                events.push(event);
            }
        }

        // Expected: ContentDelta("Hello"), ContentDelta(" World"), Done(stop, Some(usage))
        assert_eq!(events.len(), 3, "expected exactly 3 events: 2 deltas + 1 done");

        let done_count = events.iter().filter(|e| matches!(e, StreamEvent::Done { .. })).count();
        assert_eq!(done_count, 1, "expected exactly one Done event");

        // Verify the Done event has the right finish_reason and usage
        match &events[2] {
            StreamEvent::Done { finish_reason, usage } => {
                assert_eq!(*finish_reason, FinishReason::Stop);
                assert_eq!(usage.as_ref().unwrap().total_tokens, 8);
            }
            other => panic!("expected Done, got {:?}", other),
        }
    }

    /// Test streaming with tool calls followed by completion.
    #[test]
    fn test_full_streaming_with_tool_calls() {
        let adapter = OpenAiChatAdapter::new();

        let chunks = vec![
            // First chunk: tool call ID + name
            r#"{"choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"id":"call_1","type":"function","function":{"name":"search","arguments":""}}]},"finish_reason":null}]}"#,
            // Second chunk: tool call arguments fragment
            r#"{"choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"{\"query\":"}}]},"finish_reason":null}]}"#,
            // Third chunk: tool call arguments fragment
            r#"{"choices":[{"index":0,"delta":{"tool_calls":[{"index":0,"function":{"arguments":"\"hello\"}"}}]},"finish_reason":null}]}"#,
            // Final chunk: tool_calls finish reason
            r#"{"choices":[{"index":0,"delta":{},"finish_reason":"tool_calls"}]}"#,
            "[DONE]",
        ];

        let mut events: Vec<StreamEvent> = Vec::new();
        for chunk in &chunks {
            if let Some(event) = adapter.parse_sse_event(chunk).unwrap() {
                events.push(event);
            }
        }

        assert_eq!(events.len(), 4, "expected 4 events: 3 tool call deltas + 1 done");

        // Verify tool call delta chain
        match &events[0] {
            StreamEvent::ToolCallDelta { index, id, function_name, arguments_delta } => {
                assert_eq!(*index, 0);
                assert_eq!(id.as_deref(), Some("call_1"));
                assert_eq!(function_name.as_deref(), Some("search"));
                assert_eq!(arguments_delta, "");
            }
            other => panic!("expected ToolCallDelta, got {:?}", other),
        }
        match &events[1] {
            StreamEvent::ToolCallDelta { index, id, function_name, arguments_delta } => {
                assert_eq!(*index, 0);
                assert!(id.is_none());
                assert!(function_name.is_none());
                assert_eq!(arguments_delta, "{\"query\":");
            }
            other => panic!("expected ToolCallDelta, got {:?}", other),
        }
        match &events[2] {
            StreamEvent::ToolCallDelta { arguments_delta, .. } => {
                assert_eq!(arguments_delta, "\"hello\"}");
            }
            other => panic!("expected ToolCallDelta, got {:?}", other),
        }

        // Final event should be Done with tool_calls finish_reason
        match &events[3] {
            StreamEvent::Done { finish_reason, usage } => {
                assert_eq!(*finish_reason, FinishReason::ToolCall);
                assert!(usage.is_none());
            }
            other => panic!("expected Done, got {:?}", other),
        }

        let done_count = events.iter().filter(|e| matches!(e, StreamEvent::Done { .. })).count();
        assert_eq!(done_count, 1, "expected exactly one Done event");
    }

    /// Test chunk fragmentation: SSE data split across parse_sse_event boundaries.
    /// This tests the SseLineBuffer upstream, but we also verify parse_sse_event
    /// handles such split data correctly when reassembled.
    #[test]
    fn test_parse_sse_chunk_fragmentation() {
        let adapter = OpenAiChatAdapter::new();

        // Simulate a JSON payload that is split in the middle of content
        // This simulates what happens after SseLineBuffer reassembles:
        // First half:   `{"choices":[{"index":0,"delta":{"content":"Hel`
        // Second half:  `lo"},"finish_reason":null}]}`
        //
        // After reassembly, parse_sse_event receives the complete JSON.
        let full_json =
            r#"{"choices":[{"index":0,"delta":{"content":"Hello"},"finish_reason":null}]}"#;

        // Verify the complete JSON parses correctly
        let event = adapter.parse_sse_event(full_json).unwrap();
        assert_eq!(event, Some(StreamEvent::ContentDelta { delta: "Hello".into() }));
    }

    // ── Full integration test with wiremock ──

    #[tokio::test]
    async fn test_complete_streaming_via_wiremock() {
        let mock_server = wiremock::MockServer::start().await;

        // Use the shared SSE response utility from test_sse
        let sse_events = &[
            r#"{"choices":[{"index":0,"delta":{"content":"Hello"},"finish_reason":null}]}"#,
            r#"{"choices":[{"index":0,"delta":{"content":" World"},"finish_reason":null}]}"#,
            r#"{"choices":[{"index":0,"delta":{},"finish_reason":"stop"}],"usage":{"prompt_tokens":5,"completion_tokens":3,"total_tokens":8}}"#,
        ];
        // We manually build the body to include the [DONE] signal
        let body_str = {
            let mut b = String::new();
            for ev in sse_events {
                b.push_str("data: ");
                b.push_str(ev);
                b.push_str("\n\n");
            }
            b.push_str("data: [DONE]\n\n");
            b
        };

        wiremock::Mock::given(wiremock::matchers::method("POST"))
            .and(wiremock::matchers::path("/chat/completions"))
            .respond_with(wiremock::ResponseTemplate::new(200).set_body_string(body_str))
            .mount(&mock_server)
            .await;

        // Build the request
        let adapter = OpenAiChatAdapter::new();
        let request = CompletionRequest::new("gpt-4o", vec![Message::user("Hi")]);
        let req_body = adapter.build_request_body(&request, true).unwrap();
        let auth = AuthMethod::Bearer { token: "sk-test".into() };
        let headers = adapter.build_auth_headers(&auth);

        let client = reqwest::Client::new();
        let url = format!("{}/chat/completions", mock_server.uri());
        let resp =
            crate::http::build_request(&client, &url, req_body, headers, None).await.unwrap();

        assert!(resp.status().is_success());

        // Create SSE stream
        let stream = crate::http::create_sse_stream(resp, None);

        // Collect all events via parse_sse_event
        use futures::StreamExt;
        let sse_lines: Vec<String> =
            stream.filter_map(|r| futures::future::ready(r.ok())).collect().await;

        let mut events: Vec<StreamEvent> = Vec::new();
        for line in &sse_lines {
            if let Some(data) = line.strip_prefix("data: ") {
                if data == "[DONE]" {
                    continue;
                }
                if let Ok(Some(event)) = adapter.parse_sse_event(data) {
                    events.push(event);
                }
            }
        }

        // Verify: 2 content deltas + 1 done = 3 events
        assert_eq!(
            events.len(),
            3,
            "expected 3 events, got {}: {:?} (lines: {:?})",
            events.len(),
            events,
            sse_lines
        );
        assert_eq!(events[0], StreamEvent::ContentDelta { delta: "Hello".into() });
        assert_eq!(events[1], StreamEvent::ContentDelta { delta: " World".into() });
        match &events[2] {
            StreamEvent::Done { finish_reason, usage } => {
                assert_eq!(*finish_reason, FinishReason::Stop);
                let u = usage.as_ref().expect("expected usage in Done");
                assert_eq!(u.total_tokens, 8);
            }
            other => panic!("expected Done, got {:?}", other),
        }

        let done_count = events.iter().filter(|e| matches!(e, StreamEvent::Done { .. })).count();
        assert_eq!(done_count, 1, "expected exactly one Done event");
    }

    // ── Error handling via wiremock ──

    #[tokio::test]
    async fn test_error_401_via_wiremock() {
        let mock_server = wiremock::MockServer::start().await;

        wiremock::Mock::given(wiremock::matchers::method("POST"))
            .and(wiremock::matchers::path("/chat/completions"))
            .respond_with(
                wiremock::ResponseTemplate::new(401)
                    .set_body_string(r#"{"error":{"message":"Invalid API key"}}"#),
            )
            .mount(&mock_server)
            .await;

        let client = reqwest::Client::new();
        let url = format!("{}/chat/completions", mock_server.uri());
        let body = serde_json::json!({"model": "gpt-4o", "messages": []});

        let resp = crate::http::build_request(&client, &url, body, vec![], None).await.unwrap();

        assert_eq!(resp.status().as_u16(), 401);

        // Use handle_error_response for error mapping
        let status = resp.status().as_u16();
        let headers = resp.headers().clone();
        let err_body = resp.text().await.unwrap_or_default();
        let err = crate::http::handle_error_response(status, &headers, &err_body);

        assert!(matches!(err, ProviderError::Auth(m) if m.contains("Unauthorized")));
    }

    #[tokio::test]
    async fn test_error_429_via_wiremock() {
        let mock_server = wiremock::MockServer::start().await;

        wiremock::Mock::given(wiremock::matchers::method("POST"))
            .and(wiremock::matchers::path("/chat/completions"))
            .respond_with(
                wiremock::ResponseTemplate::new(429)
                    .insert_header("retry-after", "5")
                    .set_body_string("Rate limit exceeded"),
            )
            .mount(&mock_server)
            .await;

        let client = reqwest::Client::new();
        let url = format!("{}/chat/completions", mock_server.uri());
        let body = serde_json::json!({"model": "gpt-4o", "messages": []});

        let resp = crate::http::build_request(&client, &url, body, vec![], None).await.unwrap();

        let status = resp.status().as_u16();
        let headers = resp.headers().clone();
        let err_body = resp.text().await.unwrap_or_default();
        let err = crate::http::handle_error_response(status, &headers, &err_body);

        assert!(matches!(err, ProviderError::RateLimit { .. }));
    }

    #[tokio::test]
    async fn test_error_500_via_wiremock() {
        let mock_server = wiremock::MockServer::start().await;

        wiremock::Mock::given(wiremock::matchers::method("POST"))
            .and(wiremock::matchers::path("/chat/completions"))
            .respond_with(
                wiremock::ResponseTemplate::new(500)
                    .set_body_string(r#"{"error":{"message":"Internal error"}}"#),
            )
            .mount(&mock_server)
            .await;

        let client = reqwest::Client::new();
        let url = format!("{}/chat/completions", mock_server.uri());
        let body = serde_json::json!({"model": "gpt-4o", "messages": []});

        let resp = crate::http::build_request(&client, &url, body, vec![], None).await.unwrap();

        let status = resp.status().as_u16();
        let headers = resp.headers().clone();
        let err_body = resp.text().await.unwrap_or_default();
        let err = crate::http::handle_error_response(status, &headers, &err_body);

        assert!(matches!(err, ProviderError::Internal { .. }));
    }

    // ── Cancellation and Timeout tests ──

    #[tokio::test]
    async fn test_cancellation_before_stream_processing() {
        let adapter = OpenAiChatAdapter::new();

        // Create a long SSE stream
        let mut sse_body = String::new();
        for i in 0..50 {
            sse_body.push_str(&format!(
                "data: {{\"choices\":[{{\"index\":0,\"delta\":{{\"content\":\"chunk {}\"}},\"finish_reason\":null}}]}}\n\n",
                i
            ));
        }
        sse_body.push_str(
            "data: {\"choices\":[{\"index\":0,\"delta\":{},\"finish_reason\":\"stop\"}]}\n\n",
        );
        sse_body.push_str("data: [DONE]\n\n");

        let mut events: Vec<StreamEvent> = Vec::new();
        for line in sse_body.lines() {
            if let Some(data) = line.strip_prefix("data: ") {
                // After some events, simulate cancellation
                if events.len() >= 3 {
                    break;
                }
                if let Ok(Some(event)) = adapter.parse_sse_event(data) {
                    events.push(event);
                }
            }
        }

        // Should have at most 3 events (we broke at 3)
        assert!(events.len() <= 3);
        // No Done event since we cancelled before finish
        let done_count = events.iter().filter(|e| matches!(e, StreamEvent::Done { .. })).count();
        assert_eq!(done_count, 0);
    }

    #[tokio::test]
    async fn test_timeout_during_request() {
        let mock_server = wiremock::MockServer::start().await;

        // Use delayed response to trigger client-side timeout
        wiremock::Mock::given(wiremock::matchers::method("POST"))
            .and(wiremock::matchers::path("/chat/completions"))
            .respond_with(
                wiremock::ResponseTemplate::new(200)
                    .set_body_string("data: hello\n\n")
                    .set_delay(std::time::Duration::from_millis(5000)),
            )
            .mount(&mock_server)
            .await;

        let client = reqwest::Client::new();
        let url = format!("{}/chat/completions", mock_server.uri());
        let body = serde_json::json!({"model": "gpt-4o", "messages": []});

        // Use a very short timeout
        let result = crate::http::build_request(
            &client,
            &url,
            body,
            vec![],
            Some(std::time::Duration::from_millis(50)),
        )
        .await;

        assert!(result.is_err());
        let err = result.unwrap_err();
        assert!(
            matches!(err, ProviderError::Timeout { .. }),
            "expected Timeout error, got {:?}",
            err
        );
    }

    // ── New request fields tests ──

    #[test]
    fn test_build_request_body_with_new_fields() {
        let adapter = OpenAiChatAdapter::new();
        let mut request = CompletionRequest::new("deepseek-chat", vec![Message::user("Hello")]);
        request.parallel_tool_calls = Some(true);
        request.user = Some("user-abc".into());
        request.store = Some(true);
        request.metadata =
            Some(HashMap::from([("session_id".into(), Value::String("sess_1".into()))]));
        request.service_tier = Some(ServiceTier::Auto);
        request.thinking = Some(ThinkingConfig {
            thinking_type: ThinkingType::Enabled { budget_tokens: Some(4096) },
            display: None,
        });

        let body = adapter.build_request_body(&request, false).unwrap();
        assert_eq!(body["parallel_tool_calls"], true);
        assert_eq!(body["user"], "user-abc");
        assert_eq!(body["store"], true);
        assert_eq!(body["metadata"]["session_id"], "sess_1");
        assert_eq!(body["service_tier"], "auto");
        assert_eq!(body["thinking"]["type"], "enabled");
        assert_eq!(body["thinking"]["budget_tokens"], 4096);
    }

    #[test]
    fn test_build_request_body_new_fields_absent_when_none() {
        let adapter = OpenAiChatAdapter::new();
        let request = CompletionRequest::new("gpt-4o", vec![Message::user("Hi")]);
        let body = adapter.build_request_body(&request, false).unwrap();
        assert!(!body.as_object().unwrap().contains_key("parallel_tool_calls"));
        assert!(!body.as_object().unwrap().contains_key("user"));
        assert!(!body.as_object().unwrap().contains_key("store"));
        assert!(!body.as_object().unwrap().contains_key("metadata"));
        assert!(!body.as_object().unwrap().contains_key("service_tier"));
        assert!(!body.as_object().unwrap().contains_key("thinking"));
    }

    // ── New response field tests ──

    #[test]
    fn test_parse_response_with_reasoning_content() {
        let adapter = OpenAiChatAdapter::new();
        let json = serde_json::json!({
            "id": "chatcmpl-r1",
            "object": "chat.completion",
            "created": 1700000000,
            "model": "deepseek-reasoner",
            "choices": [{
                "index": 0,
                "message": {
                    "role": "assistant",
                    "content": "Final answer",
                    "reasoning_content": "Let me think through this step by step..."
                },
                "finish_reason": "stop"
            }],
            "usage": {
                "prompt_tokens": 10,
                "completion_tokens": 50,
                "total_tokens": 60
            }
        });

        let resp = adapter.parse_response(&json).unwrap();
        assert_eq!(resp.content.as_deref(), Some("Final answer"));
        assert_eq!(resp.thinking.as_deref(), Some("Let me think through this step by step..."));
        assert_eq!(resp.id.as_deref(), Some("chatcmpl-r1"));
        assert_eq!(resp.created, Some(1700000000));
    }

    #[test]
    fn test_parse_response_with_deepseek_usage() {
        let adapter = OpenAiChatAdapter::new();
        let json = serde_json::json!({
            "id": "chatcmpl-ds1",
            "object": "chat.completion",
            "model": "deepseek-chat",
            "choices": [{
                "index": 0,
                "message": { "role": "assistant", "content": "Hello" },
                "finish_reason": "stop"
            }],
            "usage": {
                "prompt_tokens": 100,
                "completion_tokens": 50,
                "total_tokens": 150,
                "prompt_tokens_details": {
                    "cached_tokens": 30,
                    "prompt_cache_hit_tokens": 20,
                    "prompt_cache_miss_tokens": 80
                },
                "completion_tokens_details": {
                    "reasoning_tokens": 15
                }
            }
        });

        let resp = adapter.parse_response(&json).unwrap();
        assert_eq!(resp.usage.cached_tokens, Some(30));
        assert_eq!(resp.usage.reasoning_tokens, Some(15));
        assert_eq!(resp.usage.prompt_cache_hit_tokens, Some(20));
        assert_eq!(resp.usage.prompt_cache_miss_tokens, Some(80));
    }

    #[test]
    fn test_parse_response_with_refusal() {
        let adapter = OpenAiChatAdapter::new();
        let json = serde_json::json!({
            "id": "chatcmpl-ref",
            "object": "chat.completion",
            "model": "gpt-4o",
            "choices": [{
                "index": 0,
                "message": {
                    "role": "assistant",
                    "content": null,
                    "refusal": "I cannot answer that question."
                },
                "finish_reason": "refusal"
            }],
            "usage": {
                "prompt_tokens": 5,
                "completion_tokens": 0,
                "total_tokens": 5
            }
        });

        let resp = adapter.parse_response(&json).unwrap();
        assert_eq!(resp.finish_reason, FinishReason::Refusal);
        assert_eq!(resp.refusal.as_deref(), Some("I cannot answer that question."));
        assert!(resp.content.is_none());
    }

    #[test]
    fn test_parse_response_system_fingerprint() {
        let adapter = OpenAiChatAdapter::new();
        let json = serde_json::json!({
            "id": "chatcmpl-fp1",
            "object": "chat.completion",
            "created": 1700000002,
            "model": "gpt-4o",
            "system_fingerprint": "fp_abc123",
            "choices": [{
                "index": 0,
                "message": { "role": "assistant", "content": "Hi" },
                "finish_reason": "stop"
            }],
            "usage": {
                "prompt_tokens": 1,
                "completion_tokens": 1,
                "total_tokens": 2
            }
        });

        let resp = adapter.parse_response(&json).unwrap();
        assert_eq!(resp.system_fingerprint.as_deref(), Some("fp_abc123"));
    }

    // ── New FinishReason tests ──

    #[test]
    fn test_parse_response_finish_reason_pause_turn() {
        let adapter = OpenAiChatAdapter::new();
        let json = serde_json::json!({
            "id": "chatcmpl-pt1",
            "object": "chat.completion",
            "model": "claude-3-opus",
            "choices": [{
                "index": 0,
                "message": { "role": "assistant", "content": "Let me pause here." },
                "finish_reason": "pause_turn"
            }],
            "usage": { "prompt_tokens": 5, "completion_tokens": 10, "total_tokens": 15 }
        });

        let resp = adapter.parse_response(&json).unwrap();
        assert_eq!(resp.finish_reason, FinishReason::PauseTurn);
    }

    #[test]
    fn test_parse_response_finish_reason_refusal() {
        let adapter = OpenAiChatAdapter::new();
        let json = serde_json::json!({
            "id": "chatcmpl-ref2",
            "object": "chat.completion",
            "model": "gpt-4o",
            "choices": [{
                "index": 0,
                "message": { "role": "assistant", "content": null },
                "finish_reason": "refusal"
            }],
            "usage": { "prompt_tokens": 5, "completion_tokens": 0, "total_tokens": 5 }
        });

        let resp = adapter.parse_response(&json).unwrap();
        assert_eq!(resp.finish_reason, FinishReason::Refusal);
    }

    #[test]
    fn test_parse_sse_finish_reason_pause_turn() {
        let adapter = OpenAiChatAdapter::new();
        let data = r#"{"choices":[{"index":0,"delta":{},"finish_reason":"pause_turn"}]}"#;
        let event = adapter.parse_sse_event(data).unwrap();
        assert_eq!(
            event,
            Some(StreamEvent::Done { finish_reason: FinishReason::PauseTurn, usage: None })
        );
    }

    #[test]
    fn test_parse_sse_finish_reason_refusal() {
        let adapter = OpenAiChatAdapter::new();
        let data = r#"{"choices":[{"index":0,"delta":{},"finish_reason":"refusal"}]}"#;
        let event = adapter.parse_sse_event(data).unwrap();
        assert_eq!(
            event,
            Some(StreamEvent::Done { finish_reason: FinishReason::Refusal, usage: None })
        );
    }

    // ── Wiremock test for reasoning_content ──

    #[tokio::test]
    async fn test_wiremock_reasoning_content() {
        let mock_server = wiremock::MockServer::start().await;

        let response_body = serde_json::json!({
            "id": "chatcmpl-r1",
            "object": "chat.completion",
            "created": 1700000000,
            "model": "deepseek-reasoner",
            "choices": [{
                "index": 0,
                "message": {
                    "role": "assistant",
                    "content": "Final answer",
                    "reasoning_content": "Step-by-step reasoning..."
                },
                "finish_reason": "stop"
            }],
            "usage": {
                "prompt_tokens": 10,
                "completion_tokens": 50,
                "total_tokens": 60
            }
        });

        wiremock::Mock::given(wiremock::matchers::method("POST"))
            .and(wiremock::matchers::path("/chat/completions"))
            .respond_with(wiremock::ResponseTemplate::new(200).set_body_json(response_body))
            .mount(&mock_server)
            .await;

        let adapter = OpenAiChatAdapter::new();
        let request = CompletionRequest::new("deepseek-reasoner", vec![Message::user("Think")]);
        let req_body = adapter.build_request_body(&request, false).unwrap();
        let auth = AuthMethod::Bearer { token: "sk-test".into() };
        let headers = adapter.build_auth_headers(&auth);

        let client = reqwest::Client::new();
        let url = format!("{}/chat/completions", mock_server.uri());
        let resp =
            crate::http::build_request(&client, &url, req_body, headers, None).await.unwrap();

        assert!(resp.status().is_success());
        let body: serde_json::Value = resp.json().await.unwrap();
        let parsed = adapter.parse_response(&body).unwrap();
        assert_eq!(parsed.content.as_deref(), Some("Final answer"));
        assert_eq!(parsed.thinking.as_deref(), Some("Step-by-step reasoning..."));
    }

    #[tokio::test]
    async fn test_wiremock_deepseek_usage() {
        let mock_server = wiremock::MockServer::start().await;

        let response_body = serde_json::json!({
            "id": "chatcmpl-ds2",
            "object": "chat.completion",
            "model": "deepseek-chat",
            "choices": [{
                "index": 0,
                "message": { "role": "assistant", "content": "Hello" },
                "finish_reason": "stop"
            }],
            "usage": {
                "prompt_tokens": 100,
                "completion_tokens": 50,
                "total_tokens": 150,
                "prompt_tokens_details": {
                    "cached_tokens": 30,
                    "prompt_cache_hit_tokens": 20,
                    "prompt_cache_miss_tokens": 80
                },
                "completion_tokens_details": {
                    "reasoning_tokens": 15
                }
            }
        });

        wiremock::Mock::given(wiremock::matchers::method("POST"))
            .and(wiremock::matchers::path("/chat/completions"))
            .respond_with(wiremock::ResponseTemplate::new(200).set_body_json(response_body))
            .mount(&mock_server)
            .await;

        let adapter = OpenAiChatAdapter::new();
        let request = CompletionRequest::new("deepseek-chat", vec![Message::user("Hi")]);
        let req_body = adapter.build_request_body(&request, false).unwrap();
        let auth = AuthMethod::Bearer { token: "sk-test".into() };
        let headers = adapter.build_auth_headers(&auth);

        let client = reqwest::Client::new();
        let url = format!("{}/chat/completions", mock_server.uri());
        let resp =
            crate::http::build_request(&client, &url, req_body, headers, None).await.unwrap();

        assert!(resp.status().is_success());
        let body: serde_json::Value = resp.json().await.unwrap();
        let parsed = adapter.parse_response(&body).unwrap();
        assert_eq!(parsed.usage.cached_tokens, Some(30));
        assert_eq!(parsed.usage.reasoning_tokens, Some(15));
        assert_eq!(parsed.usage.prompt_cache_hit_tokens, Some(20));
        assert_eq!(parsed.usage.prompt_cache_miss_tokens, Some(80));
    }

    #[tokio::test]
    async fn test_wiremock_sse_finish_reason_refusal() {
        let mock_server = wiremock::MockServer::start().await;

        let sse_body = concat!(
            "data: {\"choices\":[{\"index\":0,\"delta\":{\"content\":\"I cannot\"},\"finish_reason\":null}]}\n\n",
            "data: {\"choices\":[{\"index\":0,\"delta\":{\"content\":\" answer that.\"},\"finish_reason\":null}]}\n\n",
            "data: {\"choices\":[{\"index\":0,\"delta\":{},\"finish_reason\":\"refusal\"}]}\n\n",
            "data: [DONE]\n\n",
        );

        wiremock::Mock::given(wiremock::matchers::method("POST"))
            .and(wiremock::matchers::path("/chat/completions"))
            .respond_with(wiremock::ResponseTemplate::new(200).set_body_string(sse_body))
            .mount(&mock_server)
            .await;

        let adapter = OpenAiChatAdapter::new();
        let request = CompletionRequest::new("gpt-4o", vec![Message::user("Bad question")]);
        let req_body = adapter.build_request_body(&request, true).unwrap();
        let auth = AuthMethod::Bearer { token: "sk-test".into() };
        let headers = adapter.build_auth_headers(&auth);

        let client = reqwest::Client::new();
        let url = format!("{}/chat/completions", mock_server.uri());
        let resp =
            crate::http::build_request(&client, &url, req_body, headers, None).await.unwrap();

        assert!(resp.status().is_success());

        let stream = crate::http::create_sse_stream(resp, None);
        use futures::StreamExt;
        let sse_lines: Vec<String> =
            stream.filter_map(|r| futures::future::ready(r.ok())).collect().await;

        let mut events: Vec<StreamEvent> = Vec::new();
        for line in &sse_lines {
            if let Some(data) = line.strip_prefix("data: ") {
                if data == "[DONE]" {
                    continue;
                }
                if let Ok(Some(event)) = adapter.parse_sse_event(data) {
                    events.push(event);
                }
            }
        }

        assert_eq!(events.len(), 3, "expected 3 events: 2 deltas + 1 done");
        assert_eq!(events[0], StreamEvent::ContentDelta { delta: "I cannot".into() });
        assert_eq!(events[1], StreamEvent::ContentDelta { delta: " answer that.".into() });
        match &events[2] {
            StreamEvent::Done { finish_reason, usage } => {
                assert_eq!(*finish_reason, FinishReason::Refusal);
                assert!(usage.is_none());
            }
            other => panic!("expected Done, got {:?}", other),
        }
    }