codex/codex-rs/app-server/tests/suite/v2/image_generation.rs

use std::path::Path;
use std::time::Duration;

use anyhow::Context;
use anyhow::Result;
use app_test_support::ChatGptAuthFixture;
use app_test_support::McpProcess;
use app_test_support::to_response;
use app_test_support::write_chatgpt_auth;
use codex_app_server_protocol::ItemCompletedNotification;
use codex_app_server_protocol::JSONRPCResponse;
use codex_app_server_protocol::RequestId;
use codex_app_server_protocol::ThreadItem;
use codex_app_server_protocol::ThreadStartParams;
use codex_app_server_protocol::ThreadStartResponse;
use codex_app_server_protocol::TurnStartParams;
use codex_app_server_protocol::TurnStartResponse;
use codex_app_server_protocol::UserInput as V2UserInput;
use codex_config::types::AuthCredentialsStoreMode;
use core_test_support::responses;
use pretty_assertions::assert_eq;
use serde_json::json;
use tempfile::TempDir;
use tokio::time::timeout;
use wiremock::Mock;
use wiremock::MockServer;
use wiremock::ResponseTemplate;
use wiremock::matchers::method;
use wiremock::matchers::path;

const RESULT: &str = "cG5n";

// macOS and Windows Bazel CI can spend tens of seconds starting app-server
// subprocesses or processing test RPCs under load.
#[cfg(any(target_os = "macos", windows))]
const DEFAULT_READ_TIMEOUT: Duration = Duration::from_secs(60);
#[cfg(not(any(target_os = "macos", windows)))]
const DEFAULT_READ_TIMEOUT: Duration = Duration::from_secs(10);

#[tokio::test]
async fn standalone_image_generation_persists_image_and_returns_it_to_model() -> Result<()> {
    let call_id = "image-run-1";
    let server = responses::start_mock_server().await;
    mount_image_response(&server).await;

    let response_mock = responses::mount_sse_sequence(
        &server,
        vec![
            responses::sse(vec![
                responses::ev_response_created("resp-1"),
                responses::ev_function_call_with_namespace(
                    call_id,
                    "image_gen",
                    "imagegen",
                    &json!({
                        "action": "generate",
                        "prompt": "paint a blue whale",
                    })
                    .to_string(),
                ),
                responses::ev_completed("resp-1"),
            ]),
            responses::sse(vec![
                responses::ev_assistant_message("msg-1", "Done"),
                responses::ev_completed("resp-2"),
            ]),
        ],
    )
    .await;

    let codex_home = TempDir::new()?;
    create_config_toml(codex_home.path(), &server.uri())?;
    write_chatgpt_auth(
        codex_home.path(),
        ChatGptAuthFixture::new("access-chatgpt"),
        AuthCredentialsStoreMode::File,
    )?;

    let mut mcp = McpProcess::new_with_env(codex_home.path(), &[("OPENAI_API_KEY", None)]).await?;
    timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;

    let thread_req = mcp
        .send_thread_start_request(ThreadStartParams::default())
        .await?;
    let thread_resp: JSONRPCResponse = timeout(
        DEFAULT_READ_TIMEOUT,
        mcp.read_stream_until_response_message(RequestId::Integer(thread_req)),
    )
    .await??;
    let ThreadStartResponse { thread, .. } = to_response::<ThreadStartResponse>(thread_resp)?;

    let turn_req = mcp
        .send_turn_start_request(TurnStartParams {
            thread_id: thread.id,
            client_user_message_id: None,
            input: vec![V2UserInput::Text {
                text: "Generate an image".to_string(),
                text_elements: Vec::new(),
            }],
            ..Default::default()
        })
        .await?;
    let turn_resp: JSONRPCResponse = timeout(
        DEFAULT_READ_TIMEOUT,
        mcp.read_stream_until_response_message(RequestId::Integer(turn_req)),
    )
    .await??;
    let _turn: TurnStartResponse = to_response::<TurnStartResponse>(turn_resp)?;

    let completed = timeout(
        DEFAULT_READ_TIMEOUT,
        wait_for_image_generation_completed(&mut mcp),
    )
    .await??;
    timeout(
        DEFAULT_READ_TIMEOUT,
        mcp.read_stream_until_notification_message("turn/completed"),
    )
    .await??;

    let ThreadItem::ImageGeneration {
        status,
        revised_prompt,
        result,
        saved_path: Some(saved_path),
        ..
    } = completed.item
    else {
        panic!("expected completed image generation item with saved path");
    };
    assert_eq!(status, "completed");
    assert_eq!(revised_prompt.as_deref(), Some("paint a blue whale"));
    assert_eq!(result, RESULT);
    assert_eq!(std::fs::read(&saved_path)?, b"png");

    let requests = response_mock.requests();
    assert_eq!(requests.len(), 2);
    let output = requests[1].function_call_output(call_id);
    assert_eq!(
        output["output"][0],
        json!({
            "type": "input_image",
            "image_url": format!("data:image/png;base64,{RESULT}"),
            "detail": "high",
        })
    );
    assert_eq!(output["output"].as_array().map(Vec::len), Some(1));
    assert!(
        !requests[1]
            .message_input_texts("developer")
            .iter()
            .any(|text| text.contains("Generated images are saved to")),
        "standalone image generation should not emit the legacy developer-message hint"
    );

    Ok(())
}

async fn wait_for_image_generation_completed(
    mcp: &mut McpProcess,
) -> Result<ItemCompletedNotification> {
    loop {
        let notification = mcp
            .read_stream_until_notification_message("item/completed")
            .await?;
        let completed: ItemCompletedNotification = serde_json::from_value(
            notification
                .params
                .context("item/completed notification should include params")?,
        )?;
        if matches!(&completed.item, ThreadItem::ImageGeneration { .. }) {
            return Ok(completed);
        }
    }
}

async fn mount_image_response(server: &MockServer) {
    Mock::given(method("POST"))
        .and(path("/api/codex/images/generations"))
        .respond_with(ResponseTemplate::new(200).set_body_json(json!({
            "created": 1,
            "data": [{"b64_json": RESULT}],
        })))
        .expect(1)
        .mount(server)
        .await;
}

fn create_config_toml(codex_home: &Path, server_uri: &str) -> std::io::Result<()> {
    std::fs::write(
        codex_home.join("config.toml"),
        format!(
            r#"
model = "mock-model"
approval_policy = "never"
sandbox_mode = "read-only"
model_provider = "openai-custom"
chatgpt_base_url = "{server_uri}"

[features]
imagegenext = true

[model_providers.openai-custom]
name = "OpenAI"
base_url = "{server_uri}/api/codex"
wire_api = "responses"
request_max_retries = 0
stream_max_retries = 0
supports_websockets = false
requires_openai_auth = true
"#
        ),
    )
}