diff --git a/staging/vhost-device-sound/src/audio_backends.rs b/staging/vhost-device-sound/src/audio_backends.rs
index 1592285..05c0048 100644
--- a/staging/vhost-device-sound/src/audio_backends.rs
+++ b/staging/vhost-device-sound/src/audio_backends.rs
@@ -41,6 +41,9 @@ pub trait AudioBackend {
     fn stop(&self, _stream_id: u32) -> Result<()> {
         Ok(())
     }
+
+    #[cfg(test)]
+    fn as_any(&self) -> &dyn std::any::Any;
 }
 
 pub fn alloc_audio_backend(
@@ -56,3 +59,35 @@ pub fn alloc_audio_backend(
         BackendType::Alsa => Ok(Box::new(AlsaBackend::new(streams))),
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use std::any::TypeId;
+
+    use super::*;
+
+    #[test]
+    fn test_alloc_audio_backend() {
+        crate::init_logger();
+        {
+            let v = BackendType::Null;
+            let value = alloc_audio_backend(v, Default::default()).unwrap();
+            assert_eq!(TypeId::of::<NullBackend>(), value.as_any().type_id());
+        }
+        #[cfg(feature = "pw-backend")]
+        {
+            use pipewire::{test_utils::PipewireTestHarness, *};
+
+            let _test_harness = PipewireTestHarness::new();
+            let v = BackendType::Pipewire;
+            let value = alloc_audio_backend(v, Default::default()).unwrap();
+            assert_eq!(TypeId::of::<PwBackend>(), value.as_any().type_id());
+        }
+        #[cfg(feature = "alsa-backend")]
+        {
+            let v = BackendType::Alsa;
+            let value = alloc_audio_backend(v, Default::default()).unwrap();
+            assert_eq!(TypeId::of::<AlsaBackend>(), value.as_any().type_id());
+        }
+    }
+}
diff --git a/staging/vhost-device-sound/src/audio_backends/alsa.rs b/staging/vhost-device-sound/src/audio_backends/alsa.rs
index 410972e..8b779ed 100644
--- a/staging/vhost-device-sound/src/audio_backends/alsa.rs
+++ b/staging/vhost-device-sound/src/audio_backends/alsa.rs
@@ -718,4 +718,9 @@ impl AudioBackend for AlsaBackend {
         std::mem::take(&mut streams[stream_id as usize].buffers);
         Ok(())
     }
+
+    #[cfg(test)]
+    fn as_any(&self) -> &dyn std::any::Any {
+        self
+    }
 }
diff --git a/staging/vhost-device-sound/src/audio_backends/null.rs b/staging/vhost-device-sound/src/audio_backends/null.rs
index 3101e9b..05175f9 100644
--- a/staging/vhost-device-sound/src/audio_backends/null.rs
+++ b/staging/vhost-device-sound/src/audio_backends/null.rs
@@ -26,6 +26,11 @@ impl AudioBackend for NullBackend {
         log::trace!("NullBackend read stream_id {}", _id);
         Ok(())
     }
+
+    #[cfg(test)]
+    fn as_any(&self) -> &dyn std::any::Any {
+        self
+    }
 }
 
 #[cfg(test)]
diff --git a/staging/vhost-device-sound/src/audio_backends/pipewire.rs b/staging/vhost-device-sound/src/audio_backends/pipewire.rs
index 4528689..3cabbd2 100644
--- a/staging/vhost-device-sound/src/audio_backends/pipewire.rs
+++ b/staging/vhost-device-sound/src/audio_backends/pipewire.rs
@@ -562,12 +562,17 @@ impl AudioBackend for PwBackend {
         lock_guard.unlock();
         Ok(())
     }
+
+    #[cfg(test)]
+    fn as_any(&self) -> &dyn std::any::Any {
+        self
+    }
 }
 
 #[cfg(test)]
 /// Utilities for building a temporary Dbus session and a pipewire instance for
 /// testing.
-mod test_utils;
+pub mod test_utils;
 
 #[cfg(test)]
 mod tests {