yvgude--lean-ctx/rust/tests/p4_ctx_prefetch_eval.rs

use serde_json::json;

#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
#[allow(clippy::await_holding_lock)]
async fn ctx_prefetch_warms_cache_for_full_read() {
    let _g = lean_ctx::core::data_dir::test_env_lock();
    let dir = tempfile::tempdir().expect("tempdir");
    let data_dir = dir.path().join("data");
    std::fs::create_dir_all(&data_dir).expect("create data dir");
    // TODO: Audit that the environment access only happens in single-threaded code.
    unsafe { std::env::set_var("LEAN_CTX_DATA_DIR", &data_dir) };

    let project = tempfile::tempdir().expect("project");
    let file_a = project.path().join("a.rs");
    let file_b = project.path().join("b.rs");
    std::fs::write(&file_a, "mod b;\npub fn a() { b::b(); }\n").expect("write a");
    std::fs::write(&file_b, "pub fn b() {}\n").expect("write b");

    let engine = lean_ctx::engine::ContextEngine::with_project_root(project.path());

    let out = engine
        .call_tool_text(
            "ctx_prefetch",
            Some(json!({
                "root": project.path().to_string_lossy().to_string(),
                "changed_files": [file_a.to_string_lossy().to_string()],
                "budget_tokens": 500,
                "max_files": 2
            })),
        )
        .await
        .expect("prefetch");
    assert!(out.contains("prefetched"), "prefetch out: {out}");

    let full = engine
        .call_tool_text(
            "ctx_read",
            Some(json!({"path": file_a.to_string_lossy().to_string(), "mode":"full"})),
        )
        .await
        .expect("read full");
    assert!(
        full.contains("unchanged") || full.contains("cached") || full.is_empty(),
        "expected cache hit, got: {full}"
    );

    // TODO: Audit that the environment access only happens in single-threaded code.
    unsafe { std::env::remove_var("LEAN_CTX_DATA_DIR") };
}