E2E drop check for memory leaks

crates/librqbit/src/tests/test_util.rs

@@ -1,8 +1,13 @@
-use std::{io::Write, path::Path};
+use std::{
+    io::Write,
+    path::Path,
+    sync::{Arc, Weak},
+};
 
 use anyhow::Context;
 use axum::{response::IntoResponse, routing::get, Router};
 use librqbit_core::Id20;
+use parking_lot::RwLock;
 use rand::{thread_rng, Rng, RngCore, SeedableRng};
 use tempfile::TempDir;
 use tracing::{debug, info};
@@ -124,3 +129,32 @@ async fn debug_server() -> anyhow::Result<()> {
 pub fn spawn_debug_server() {
     tokio::spawn(debug_server());
 }
+
+pub trait DropPlaceholder: Send + Sync {}
+impl<T: Send + Sync> DropPlaceholder for T {}
+
+struct DropCheck {
+    obj: Weak<dyn DropPlaceholder>,
+    name: String,
+}
+
+#[derive(Default, Clone)]
+pub struct DropChecks(Arc<RwLock<Vec<DropCheck>>>);
+
+impl DropChecks {
+    pub fn add<T: DropPlaceholder + 'static, S: Into<String>>(&self, obj: &Arc<T>, name: S) {
+        let weak = Arc::downgrade(obj);
+        self.0.write().push(DropCheck {
+            obj: weak as Weak<dyn DropPlaceholder>,
+            name: name.into(),
+        })
+    }
+}
+
+impl Drop for DropCheck {
+    fn drop(&mut self) {
+        if self.obj.upgrade().is_some() {
+            panic!("memory leak: {}", self.name);
+        }
+    }
+}