Add daemon startup smoke test and let it run on a PC in debug_mode

v0.11.0 shipped a daemon binary that built fine but didn't actually serve
a working frontend. CI was green. Nothing in the pipeline asserted that
the built binary comes up and serves something.

Add daemon/tests/smoke.rs as an integration test that spawns the built
binary against a tempdir-backed config with debug_mode = true, picks an
ephemeral port, and asserts:

- GET /index.html is 2xx and the decompressed body contains "Rayhunter"
- GET /api/qmdl-manifest is 2xx
- the daemon exits cleanly on SIGINT

Captures the daemon's stderr into a buffer so startup/shutdown failures
print actionable context instead of just "did not start listening".

Runs as part of the regular cargo test invocation, no new CI job.

For the smoke test (and #826) to work, the daemon needs to come up on a
PC without /dev/diag, a screen, or wpa_supplicant. The DIAG read thread,
display driver, and key input were already gated on debug_mode. Gate the
two remaining device-dependent workers the same way:

- run_battery_notification_worker (polls battery sysfs paths)
- wifi_station::run_wifi_client (talks to wpa_supplicant)

doc/installing-from-source.md gains a "Running the daemon on your PC"
section. doc/porting.md drops its duplicate debug_mode line and links to
the new section.

Closes #826.

Cargo.lock

@@ -274,6 +274,19 @@ dependencies = [
  "pin-project-lite",
 ]
 
+[[package]]
+name = "async-compression"
+version = "0.4.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "93c1f86859c1af3d514fa19e8323147ff10ea98684e6c7b307912509f50e67b2"
+dependencies = [
+ "compression-codecs",
+ "compression-core",
+ "futures-core",
+ "pin-project-lite",
+ "tokio",
+]
+
 [[package]]
 name = "async-executor"
 version = "1.13.3"
@@ -992,6 +1005,23 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "compression-codecs"
+version = "0.4.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "680dc087785c5230f8e8843e2e57ac7c1c90488b6a91b88caa265410568f441b"
+dependencies = [
+ "compression-core",
+ "flate2",
+ "memchr",
+]
+
+[[package]]
+name = "compression-core"
+version = "0.4.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cc14f565cf027a105f7a44ccf9e5b424348421a1d8952a8fc9d499d313107789"
+
 [[package]]
 name = "concurrent-queue"
 version = "2.5.0"
@@ -4988,6 +5018,7 @@ version = "0.12.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "eabf4c97d9130e2bf606614eb937e86edac8292eaa6f422f995d7e8de1eb1813"
 dependencies = [
+ "async-compression",
  "base64 0.22.1",
  "bytes",
  "futures-core",

daemon/Cargo.toml

@@ -47,3 +47,7 @@ rustls-post-quantum = { version = "0.2.4", optional = true }
 async-trait = "0.1.88"
 utoipa = { version = "5.4.0", optional = true }
 url = "2.5.4"
+
+[dev-dependencies]
+reqwest = { version = "0.12.20", default-features = false, features = ["gzip"] }
+tempfile = "3.10.2"

daemon/src/main.rs

@@ -277,12 +277,14 @@ async fn run_with_config(
         analysis_tx.clone(),
     );
 
-    run_battery_notification_worker(
+    if !config.debug_mode {
-        &task_tracker,
+        run_battery_notification_worker(
-        config.device.clone(),
+            &task_tracker,
-        notification_service.new_handler(),
+            config.device.clone(),
-        shutdown_token.clone(),
+            notification_service.new_handler(),
-    );
+            shutdown_token.clone(),
+        );
+    }
 
     run_notification_worker(
         &task_tracker,
@@ -291,12 +293,14 @@ async fn run_with_config(
     );
 
     let wifi_status = Arc::new(RwLock::new(WifiStatus::default()));
-    wifi_station::run_wifi_client(
+    if !config.debug_mode {
-        &task_tracker,
+        wifi_station::run_wifi_client(
-        &config.wifi_config(),
+            &task_tracker,
-        shutdown_token.clone(),
+            &config.wifi_config(),
-        wifi_status.clone(),
+            shutdown_token.clone(),
-    );
+            wifi_status.clone(),
+        );
+    }
 
     if !config.webdav.url.trim().is_empty() {
         run_webdav_upload_worker(

daemon/tests/smoke.rs

@@ -0,0 +1,185 @@
+use std::io::Read;
+use std::net::{TcpListener, TcpStream};
+use std::process::{Child, Command, ExitStatus, Stdio};
+use std::sync::{Arc, Mutex};
+use std::time::{Duration, Instant};
+
+use tempfile::TempDir;
+
+const STARTUP_TIMEOUT: Duration = Duration::from_secs(5);
+const REQUEST_TIMEOUT: Duration = Duration::from_secs(5);
+const SHUTDOWN_TIMEOUT: Duration = Duration::from_secs(5);
+
+struct DaemonGuard {
+    child: Option<Child>,
+    stderr: Arc<Mutex<Vec<u8>>>,
+}
+
+impl DaemonGuard {
+    fn stderr_dump(&self) -> String {
+        let buf = self.stderr.lock().unwrap();
+        String::from_utf8_lossy(&buf).into_owned()
+    }
+
+    fn shutdown(&mut self, timeout: Duration) -> std::io::Result<ExitStatus> {
+        let mut child = self
+            .child
+            .take()
+            .expect("daemon already shut down or never started");
+
+        #[cfg(unix)]
+        {
+            let pid = child.id() as libc::pid_t;
+            // SAFETY: child.id() returns the OS pid of a process we own.
+            unsafe { libc::kill(pid, libc::SIGINT) };
+        }
+        #[cfg(not(unix))]
+        {
+            let _ = child.kill();
+        }
+
+        let start = Instant::now();
+        loop {
+            match child.try_wait()? {
+                Some(status) => return Ok(status),
+                None => {
+                    if start.elapsed() >= timeout {
+                        let _ = child.kill();
+                        return child.wait();
+                    }
+                    std::thread::sleep(Duration::from_millis(50));
+                }
+            }
+        }
+    }
+}
+
+impl Drop for DaemonGuard {
+    fn drop(&mut self) {
+        if let Some(mut child) = self.child.take() {
+            let _ = child.kill();
+            let _ = child.wait();
+        }
+    }
+}
+
+fn pick_free_port() -> u16 {
+    let listener = TcpListener::bind("127.0.0.1:0").expect("bind ephemeral port");
+    listener.local_addr().expect("local_addr").port()
+}
+
+fn wait_for_port(port: u16, timeout: Duration) -> bool {
+    let start = Instant::now();
+    while start.elapsed() < timeout {
+        if TcpStream::connect(("127.0.0.1", port)).is_ok() {
+            return true;
+        }
+        std::thread::sleep(Duration::from_millis(100));
+    }
+    false
+}
+
+#[tokio::test(flavor = "current_thread")]
+async fn daemon_serves_index_and_api() {
+    let port = pick_free_port();
+
+    let tmp = TempDir::new().unwrap();
+    let qmdl_dir = tmp.path().join("qmdl");
+    std::fs::create_dir(&qmdl_dir).unwrap();
+    // The daemon refuses to create a store in debug_mode, so seed an empty
+    // manifest. See init_qmdl_store in daemon/src/main.rs.
+    std::fs::write(qmdl_dir.join("manifest.toml"), "entries = []\n").unwrap();
+
+    let config_path = tmp.path().join("config.toml");
+    std::fs::write(
+        &config_path,
+        format!(
+            "qmdl_store_path = \"{}\"\nport = {}\ndebug_mode = true\n",
+            qmdl_dir.display(),
+            port,
+        ),
+    )
+    .unwrap();
+
+    let daemon_bin = env!("CARGO_BIN_EXE_rayhunter-daemon");
+    let mut child = Command::new(daemon_bin)
+        .arg(&config_path)
+        .stdout(Stdio::null())
+        .stderr(Stdio::piped())
+        .spawn()
+        .expect("failed to spawn daemon");
+
+    let stderr_buf: Arc<Mutex<Vec<u8>>> = Arc::new(Mutex::new(Vec::new()));
+    if let Some(mut pipe) = child.stderr.take() {
+        let sink = stderr_buf.clone();
+        std::thread::spawn(move || {
+            let mut chunk = [0u8; 4096];
+            loop {
+                match pipe.read(&mut chunk) {
+                    Ok(0) | Err(_) => break,
+                    Ok(n) => sink.lock().unwrap().extend_from_slice(&chunk[..n]),
+                }
+            }
+        });
+    }
+
+    let mut guard = DaemonGuard {
+        child: Some(child),
+        stderr: stderr_buf,
+    };
+
+    if !wait_for_port(port, STARTUP_TIMEOUT) {
+        panic!(
+            "daemon did not start listening on {port} within {STARTUP_TIMEOUT:?}\n--- daemon stderr ---\n{}",
+            guard.stderr_dump(),
+        );
+    }
+
+    // reqwest's rustls backend gets pulled in via feature unification with the
+    // daemon's production deps. The test process needs its own crypto provider.
+    rayhunter_daemon::crypto_provider::install_default();
+
+    let client = reqwest::Client::builder()
+        .timeout(REQUEST_TIMEOUT)
+        .gzip(true)
+        .build()
+        .unwrap();
+    let base = format!("http://127.0.0.1:{port}");
+
+    let resp = client
+        .get(format!("{base}/index.html"))
+        .send()
+        .await
+        .expect("GET /index.html failed");
+    assert!(
+        resp.status().is_success(),
+        "GET /index.html returned {}",
+        resp.status(),
+    );
+    let body = resp.text().await.expect("could not read index.html body");
+    assert!(
+        body.contains("Rayhunter"),
+        "decompressed index.html body did not contain 'Rayhunter' marker (len={})",
+        body.len(),
+    );
+
+    let resp = client
+        .get(format!("{base}/api/qmdl-manifest"))
+        .send()
+        .await
+        .expect("GET /api/qmdl-manifest failed");
+    assert!(
+        resp.status().is_success(),
+        "GET /api/qmdl-manifest returned {}",
+        resp.status(),
+    );
+
+    let status = guard
+        .shutdown(SHUTDOWN_TIMEOUT)
+        .expect("waiting for daemon exit failed");
+    assert!(
+        status.success(),
+        "daemon did not exit cleanly after SIGINT: {status}\n--- daemon stderr ---\n{}",
+        guard.stderr_dump(),
+    );
+}

doc/installing-from-source.md

@@ -27,6 +27,25 @@ Then you can build everything with:
 ./scripts/install-dev.sh orbic  # replace 'orbic' with your device type
 ```
 
+## Running the daemon on your PC
+
+If you don't have a target device handy, you can run `rayhunter-daemon` on your
+PC with `debug_mode = true`. This skips DIAG, the device display, key input,
+the battery worker, and the WiFi client, so recording-related endpoints will
+not work, but the frontend and read-only APIs do.
+
+```sh
+mkdir -p ./qmdl && printf 'entries = []\n' > ./qmdl/manifest.toml
+cat > config.toml <<'EOF'
+qmdl_store_path = "./qmdl"
+port = 8080
+debug_mode = true
+EOF
+cargo run -p rayhunter-daemon -- ./config.toml
+```
+
+Open `http://127.0.0.1:8080`.
+
 ## Hot-reloading the frontend
 
 If you are working on the frontend, you normally have to repeat all of the above steps everytime to see a change.

doc/porting.md

@@ -55,7 +55,7 @@ You can copy the daemon and config files to the device using `netcat` or `adb pu
 
 The `device` setting in `config.toml` must match one of the lowercase variant names from the `Device` enum (e.g. `"orbic"`, `"tplink"`). This controls which display driver is used.
 
-Setting `debug_mode = true` in `config.toml` runs the daemon without `/dev/diag`, so you can test the display and web UI without the hardware.
+To bring the daemon up without `/dev/diag` (for instance, to test the display and web UI before the hardware path works), see [Running the daemon on your PC](./installing-from-source.md#running-the-daemon-on-your-pc).
 
 ### Autostart