diff --git a/maitake-sync/src/mutex/tests.rs b/maitake-sync/src/mutex/tests.rs
index 43b7b147..a3d4cc2c 100644
--- a/maitake-sync/src/mutex/tests.rs
+++ b/maitake-sync/src/mutex/tests.rs
@@ -1,6 +1,6 @@
-use mutex_traits::ScopedRawMutex;
-
+use super::*;
 use crate::loom::{self, future};
+use crate::util::test::{assert_future, NopRawMutex};
 use crate::Mutex;
 
 #[test]
@@ -57,49 +57,11 @@ fn basic_multi_threaded() {
     });
 }
 
-struct NopRawMutex;
-
-unsafe impl ScopedRawMutex for NopRawMutex {
-    fn try_with_lock<R>(&self, _: impl FnOnce() -> R) -> Option<R> {
-        None
-    }
-
-    fn with_lock<R>(&self, _: impl FnOnce() -> R) -> R {
-        unimplemented!("this doesn't actually do anything")
-    }
-
-    fn is_locked(&self) -> bool {
-        true
-    }
-}
-
-fn assert_future<F: core::future::Future>(_: F) {}
-
 #[test]
 fn lock_future_impls_future() {
-    loom::model(|| {
-        // Mutex with `DefaultMutex` as the `ScopedRawMutex` implementation
-        let mutex = Mutex::new(());
-        assert_future(mutex.lock());
-
-        // Mutex with a custom `ScopedRawMutex` implementation
-        let mutex = Mutex::new_with_raw_mutex((), NopRawMutex);
-        assert_future(mutex.lock());
-    })
-}
-
-#[test]
-#[cfg(feature = "alloc")]
-fn lock_owned_future_impls_future() {
-    loom::model(|| {
-        use alloc::sync::Arc;
-
-        // Mutex with `DefaultMutex` as the `ScopedRawMutex` implementation
-        let mutex = Arc::new(Mutex::new(()));
-        assert_future(mutex.lock_owned());
+    // Mutex with `DefaultMutex` as the `ScopedRawMutex` implementation
+    assert_future::<Lock<'_, ()>>();
 
-        // Mutex with a custom `ScopedRawMutex` implementation
-        let mutex = Arc::new(Mutex::new_with_raw_mutex((), NopRawMutex));
-        assert_future(mutex.lock_owned());
-    })
+    // Mutex with a custom `ScopedRawMutex` implementation
+    assert_future::<Lock<'_, (), NopRawMutex>>();
 }
diff --git a/maitake-sync/src/rwlock/tests.rs b/maitake-sync/src/rwlock/tests.rs
index 86edfa09..67167c3d 100644
--- a/maitake-sync/src/rwlock/tests.rs
+++ b/maitake-sync/src/rwlock/tests.rs
@@ -1,5 +1,5 @@
 use super::*;
-use crate::util;
+use crate::util::test::assert_send_sync;
 
 #[cfg(any(loom, feature = "alloc"))]
 mod loom;
@@ -9,15 +9,15 @@ mod sequential;
 
 #[test]
 fn lock_is_send_sync() {
-    util::test::assert_send_sync::<RwLock<usize>>();
+    assert_send_sync::<RwLock<usize>>();
 }
 
 #[test]
 fn read_guard_is_send_sync() {
-    util::test::assert_send_sync::<RwLockReadGuard<'_, usize>>();
+    assert_send_sync::<RwLockReadGuard<'_, usize>>();
 }
 
 #[test]
 fn write_guard_is_send_sync() {
-    util::test::assert_send_sync::<RwLockWriteGuard<'_, usize>>();
+    assert_send_sync::<RwLockWriteGuard<'_, usize>>();
 }
diff --git a/maitake-sync/src/semaphore/tests.rs b/maitake-sync/src/semaphore/tests.rs
index 0cc68dc7..4381dbed 100644
--- a/maitake-sync/src/semaphore/tests.rs
+++ b/maitake-sync/src/semaphore/tests.rs
@@ -1,19 +1,28 @@
 use super::*;
-use crate::util;
+use crate::util::test::{assert_future, assert_send_sync, NopRawMutex};
 
 #[test]
 fn semaphore_is_send_and_sync() {
-    util::test::assert_send_sync::<Semaphore>();
+    assert_send_sync::<Semaphore>();
 }
 
 #[test]
 fn permit_is_send_and_sync() {
-    util::test::assert_send_sync::<Permit<'_>>();
+    assert_send_sync::<Permit<'_>>();
 }
 
 #[test]
 fn acquire_is_send_and_sync() {
-    util::test::assert_send_sync::<crate::semaphore::Acquire<'_>>();
+    assert_send_sync::<crate::semaphore::Acquire<'_>>();
+}
+
+#[test]
+fn acquire_is_future() {
+    // Semaphore with `DefaultRawMutex`
+    assert_future::<Acquire<'_>>();
+
+    // Semaphore with overridden `ScopedRawMutex`
+    assert_future::<Acquire<'_, NopRawMutex>>();
 }
 
 #[cfg(feature = "alloc")]
@@ -22,12 +31,18 @@ mod owned {
 
     #[test]
     fn owned_permit_is_send_and_sync() {
-        util::test::assert_send_sync::<OwnedPermit>();
+        assert_send_sync::<OwnedPermit>();
     }
 
     #[test]
     fn acquire_owned_is_send_and_sync() {
-        util::test::assert_send_sync::<AcquireOwned>();
+        assert_send_sync::<AcquireOwned>();
+    }
+
+    #[test]
+    fn acquire_owned_is_future() {
+        assert_future::<AcquireOwned>();
+        assert_future::<AcquireOwned<NopRawMutex>>();
     }
 }
 
diff --git a/maitake-sync/src/util.rs b/maitake-sync/src/util.rs
index 0e4b5a08..6fb5dba6 100644
--- a/maitake-sync/src/util.rs
+++ b/maitake-sync/src/util.rs
@@ -263,4 +263,27 @@ pub(crate) mod test {
     #[allow(dead_code)]
     pub(crate) fn assert_sync<T: Sync>() {}
     pub(crate) fn assert_send_sync<T: Send + Sync>() {}
+
+    pub(crate) fn assert_future<F: core::future::Future>() {}
+
+    pub(crate) struct NopRawMutex;
+
+    unsafe impl mutex_traits::RawMutex for NopRawMutex {
+        type GuardMarker = ();
+        fn lock(&self) {
+            unimplemented!("don't actually try to lock this thing")
+        }
+
+        fn is_locked(&self) -> bool {
+            unimplemented!("don't actually try to lock this thing")
+        }
+
+        fn try_lock(&self) -> bool {
+            unimplemented!("don't actually try to lock this thing")
+        }
+
+        unsafe fn unlock(&self) {
+            unimplemented!("don't actually try to lock this thing")
+        }
+    }
 }
diff --git a/maitake-sync/src/wait_map/tests.rs b/maitake-sync/src/wait_map/tests.rs
index f4165fad..73f0957f 100644
--- a/maitake-sync/src/wait_map/tests.rs
+++ b/maitake-sync/src/wait_map/tests.rs
@@ -1,5 +1,24 @@
 use super::*;
+use crate::util::test::{assert_future, NopRawMutex};
 #[cfg(all(not(loom), feature = "alloc"))]
 mod alloc_tests;
 #[cfg(any(loom, feature = "alloc"))]
 mod loom;
+
+#[test]
+fn wait_future_is_future() {
+    // WaitMap with default mutex.
+    assert_future::<Wait<'_, i32, i32>>();
+
+    // WaitMap with overridden `ScopedRawMutex`.
+    assert_future::<Wait<'_, i32, i32, NopRawMutex>>();
+}
+
+#[test]
+fn subscribe_future_is_future() {
+    // WaitMap with default mutex.
+    assert_future::<Subscribe<'_, '_, i32, i32>>();
+
+    // WaitMap with overridden `ScopedRawMutex`.
+    assert_future::<Subscribe<'_, '_, i32, i32, NopRawMutex>>();
+}
diff --git a/maitake-sync/src/wait_map/tests/alloc_tests.rs b/maitake-sync/src/wait_map/tests/alloc_tests.rs
index 9d6b6988..d225cc0b 100644
--- a/maitake-sync/src/wait_map/tests/alloc_tests.rs
+++ b/maitake-sync/src/wait_map/tests/alloc_tests.rs
@@ -1,5 +1,6 @@
 use super::super::*;
 use crate::loom::sync::Arc;
+use crate::util::test::{assert_future, NopRawMutex};
 use core::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
 use futures::{future::poll_fn, pin_mut, select_biased, FutureExt};
 use tokio_test::{assert_pending, assert_ready, assert_ready_err, task};
@@ -402,3 +403,12 @@ fn drop_wake_bailed() {
     assert_eq!(KEY_DROPS.load(Ordering::Relaxed), TASKS);
     assert_eq!(VAL_DROPS.load(Ordering::Relaxed), TASKS);
 }
+
+#[test]
+fn wait_owned_future_is_future() {
+    // WaitMap with default mutex.
+    assert_future::<WaitOwned<i32, i32>>();
+
+    // WaitMap with overridden `ScopedRawMutex`.
+    assert_future::<WaitOwned<i32, i32, NopRawMutex>>();
+}
diff --git a/maitake-sync/src/wait_queue/tests.rs b/maitake-sync/src/wait_queue/tests.rs
index 52843ef5..cfed9e2d 100644
--- a/maitake-sync/src/wait_queue/tests.rs
+++ b/maitake-sync/src/wait_queue/tests.rs
@@ -1,8 +1,16 @@
-#[cfg(any(loom, feature = "alloc"))]
 use super::*;
+use crate::util::test::{assert_future, NopRawMutex};
 
 #[cfg(all(not(loom), feature = "alloc"))]
 mod alloc_tests;
 
 #[cfg(any(loom, feature = "alloc"))]
 mod loom;
+
+#[test]
+fn wait_future_is_future() {
+    // WaitQueue with default raw mutex
+    assert_future::<Wait<'_>>();
+    // WaitQueue with overridden raw mutex
+    assert_future::<Wait<'_, NopRawMutex>>();
+}
diff --git a/maitake-sync/src/wait_queue/tests/alloc_tests.rs b/maitake-sync/src/wait_queue/tests/alloc_tests.rs
index 802f575c..80326851 100644
--- a/maitake-sync/src/wait_queue/tests/alloc_tests.rs
+++ b/maitake-sync/src/wait_queue/tests/alloc_tests.rs
@@ -1,5 +1,6 @@
 use super::*;
 use crate::loom::sync::Arc;
+use crate::util::test::{assert_future, NopRawMutex};
 use core::sync::atomic::{AtomicUsize, Ordering};
 use tokio_test::{assert_pending, assert_ready, assert_ready_ok, task};
 
@@ -169,3 +170,12 @@ fn subscribe_consumes_wakeup() {
     let mut future2 = task::spawn(q.wait());
     future2.enter(|_, f| assert_pending!(f.subscribe()));
 }
+
+#[test]
+fn wait_owned_future_is_future() {
+    // WaitQueue with default raw mutex
+    assert_future::<WaitOwned>();
+
+    // WaitQueue with overridden raw mutex
+    assert_future::<WaitOwned<NopRawMutex>>();
+}