diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f7ead4b..b9b2cb2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -80,7 +80,6 @@ jobs:
           - x86_64-pc-windows-gnu
           - i686-unknown-linux-gnu
           - powerpc64-unknown-linux-gnu
-          - mips64-unknown-linux-gnuabi64
           - riscv64gc-unknown-linux-gnu
     runs-on: ubuntu-latest
     steps:
diff --git a/ci/sanitizer.sh b/ci/sanitizer.sh
index 22ff3d5..0acecdc 100755
--- a/ci/sanitizer.sh
+++ b/ci/sanitizer.sh
@@ -6,11 +6,11 @@ export ASAN_OPTIONS="detect_odr_violation=0 detect_leaks=0"
 
 # Run address sanitizer with cargo-hack
 RUSTFLAGS="-Z sanitizer=address" \
-cargo hack test --lib --each-feature
+cargo hack test --lib --each-feature --include-features sync,async --exclude-no-default-features
 
 # Run leak sanitizer with cargo-hack
 RUSTFLAGS="-Z sanitizer=leak" \
-cargo hack test --lib --each-feature
+cargo hack test --lib --each-feature --include-features sync,async --exclude-no-default-features
 
 # Run thread sanitizer with cargo-hack
 RUSTFLAGS="-Z sanitizer=thread" \
diff --git a/src/policy/test.rs b/src/policy/test.rs
index b1fdf34..2206622 100644
--- a/src/policy/test.rs
+++ b/src/policy/test.rs
@@ -1,166 +1,172 @@
 use crate::metrics::Metrics;
-use crate::policy::{LFUPolicy, SampledLFU, TinyLFU};
+use crate::policy::{SampledLFU, TinyLFU};
 use std::collections::hash_map::RandomState;
-use std::sync::Arc;
+
 use std::time::Duration;
 
 static WAIT: Duration = Duration::from_millis(100);
 
-use std::thread::sleep;
+#[cfg(feature = "sync")]
+mod sync_test {
+    use super::*;
+    use crate::policy::LFUPolicy;
+    use std::sync::Arc;
+    use std::thread::sleep;
 
-#[test]
-fn test_policy() {
-    let _ = LFUPolicy::new(100, 10);
-}
+    #[test]
+    fn test_policy() {
+        let _ = LFUPolicy::new(100, 10);
+    }
 
-#[test]
-fn test_policy_metrics() {
-    let mut p = LFUPolicy::new(100, 10).unwrap();
-    p.collect_metrics(Arc::new(Metrics::new_op()));
-    assert!(p.metrics.is_op());
-    assert!(p.inner.lock().costs.metrics.is_op());
-}
+    #[test]
+    fn test_policy_metrics() {
+        let mut p = LFUPolicy::new(100, 10).unwrap();
+        p.collect_metrics(Arc::new(Metrics::new_op()));
+        assert!(p.metrics.is_op());
+        assert!(p.inner.lock().costs.metrics.is_op());
+    }
 
-#[test]
-fn test_policy_process_items() {
-    let p = LFUPolicy::new(100, 10).unwrap();
-    p.items_tx.send(vec![1, 2, 2]).unwrap();
-    sleep(WAIT);
-    let inner = p.inner.lock();
-    assert_eq!(inner.admit.estimate(2), 2);
-    assert_eq!(inner.admit.estimate(1), 1);
-    drop(inner);
-
-    p.stop_tx.send(()).unwrap();
-    sleep(WAIT);
-    assert!(p.push(vec![3, 3, 3]).is_err());
-    let inner = p.inner.lock();
-    assert_eq!(inner.admit.estimate(3), 0);
-}
+    #[test]
+    fn test_policy_process_items() {
+        let p = LFUPolicy::new(100, 10).unwrap();
+        p.items_tx.send(vec![1, 2, 2]).unwrap();
+        sleep(WAIT);
+        let inner = p.inner.lock();
+        assert_eq!(inner.admit.estimate(2), 2);
+        assert_eq!(inner.admit.estimate(1), 1);
+        drop(inner);
 
-#[test]
-fn test_policy_push() {
-    let p = LFUPolicy::new(100, 10).unwrap();
-    assert!(p.push(vec![]).unwrap());
-
-    let mut keep_count = 0;
-    (0..10).for_each(|_| {
-        if p.push(vec![1, 2, 3, 4, 5]).unwrap() {
-            keep_count += 1;
-        }
-    });
+        p.stop_tx.send(()).unwrap();
+        sleep(WAIT);
+        assert!(p.push(vec![3, 3, 3]).is_err());
+        let inner = p.inner.lock();
+        assert_eq!(inner.admit.estimate(3), 0);
+    }
 
-    assert_ne!(0, keep_count);
-}
+    #[test]
+    fn test_policy_push() {
+        let p = LFUPolicy::new(100, 10).unwrap();
+        assert!(p.push(vec![]).unwrap());
 
-#[test]
-fn test_policy_add() {
-    let p = LFUPolicy::new(1000, 100).unwrap();
-    let (victims, added) = p.add(1, 101);
-    assert!(victims.is_none());
-    assert!(!added);
-
-    let mut inner = p.inner.lock();
-    inner.costs.increment(1, 1);
-    inner.admit.increment(1);
-    inner.admit.increment(2);
-    inner.admit.increment(3);
-    drop(inner);
-
-    let (victims, added) = p.add(1, 1);
-    assert!(victims.is_none());
-    assert!(!added);
-
-    let (victims, added) = p.add(2, 20);
-    assert!(victims.is_none());
-    assert!(added);
-
-    let (victims, added) = p.add(3, 90);
-    assert!(victims.is_some());
-    assert!(added);
-
-    let (victims, added) = p.add(4, 20);
-    assert!(victims.is_some());
-    assert!(!added);
-}
+        let mut keep_count = 0;
+        (0..10).for_each(|_| {
+            if p.push(vec![1, 2, 3, 4, 5]).unwrap() {
+                keep_count += 1;
+            }
+        });
 
-#[test]
-fn test_policy_has() {
-    let p = LFUPolicy::new(100, 10).unwrap();
-    p.add(1, 1);
-    assert!(p.contains(&1));
-    assert!(!p.contains(&2));
-}
+        assert_ne!(0, keep_count);
+    }
 
-#[test]
-fn test_policy_del() {
-    let p = LFUPolicy::new(100, 10).unwrap();
-    p.add(1, 1);
-    p.remove(&1);
-    p.remove(&2);
-    assert!(!p.contains(&1));
-    assert!(!p.contains(&2));
-}
+    #[test]
+    fn test_policy_add() {
+        let p = LFUPolicy::new(1000, 100).unwrap();
+        let (victims, added) = p.add(1, 101);
+        assert!(victims.is_none());
+        assert!(!added);
 
-#[test]
-fn test_policy_cap() {
-    let p = LFUPolicy::new(100, 10).unwrap();
-    p.add(1, 1);
-    assert_eq!(p.cap(), 9);
-}
+        let mut inner = p.inner.lock();
+        inner.costs.increment(1, 1);
+        inner.admit.increment(1);
+        inner.admit.increment(2);
+        inner.admit.increment(3);
+        drop(inner);
 
-#[test]
-fn test_policy_update() {
-    let p = LFUPolicy::new(100, 10).unwrap();
-    p.add(1, 1);
-    p.update(&1, 2);
-    let inner = p.inner.lock();
-    assert_eq!(inner.costs.key_costs.get(&1).unwrap(), &2);
-}
+        let (victims, added) = p.add(1, 1);
+        assert!(victims.is_none());
+        assert!(!added);
 
-#[test]
-fn test_policy_cost() {
-    let p = LFUPolicy::new(100, 10).unwrap();
-    p.add(1, 2);
-    assert_eq!(p.cost(&1), 2);
-    assert_eq!(p.cost(&2), -1);
-}
+        let (victims, added) = p.add(2, 20);
+        assert!(victims.is_none());
+        assert!(added);
 
-#[test]
-fn test_policy_clear() {
-    let p = LFUPolicy::new(100, 10).unwrap();
-    p.add(1, 1);
-    p.add(2, 2);
-    p.add(3, 3);
-    p.clear();
-
-    assert_eq!(p.cap(), 10);
-    assert!(!p.contains(&2));
-    assert!(!p.contains(&2));
-    assert!(!p.contains(&3));
-}
+        let (victims, added) = p.add(3, 90);
+        assert!(victims.is_some());
+        assert!(added);
 
-#[test]
-fn test_policy_close() {
-    let p = LFUPolicy::new(100, 10).unwrap();
-    p.add(1, 1);
-    let _ = p.close();
-    sleep(WAIT);
-    assert!(p.items_tx.send(vec![1]).is_err())
-}
+        let (victims, added) = p.add(4, 20);
+        assert!(victims.is_some());
+        assert!(!added);
+    }
 
-#[test]
-fn test_policy_push_after_close() {
-    let p = LFUPolicy::new(100, 10).unwrap();
-    let _ = p.close();
-    assert!(!p.push(vec![1, 2]).unwrap());
-}
+    #[test]
+    fn test_policy_has() {
+        let p = LFUPolicy::new(100, 10).unwrap();
+        p.add(1, 1);
+        assert!(p.contains(&1));
+        assert!(!p.contains(&2));
+    }
 
-#[test]
-fn test_policy_add_after_close() {
-    let p = LFUPolicy::new(100, 10).unwrap();
-    let _ = p.close();
-    p.add(1, 1);
+    #[test]
+    fn test_policy_del() {
+        let p = LFUPolicy::new(100, 10).unwrap();
+        p.add(1, 1);
+        p.remove(&1);
+        p.remove(&2);
+        assert!(!p.contains(&1));
+        assert!(!p.contains(&2));
+    }
+
+    #[test]
+    fn test_policy_cap() {
+        let p = LFUPolicy::new(100, 10).unwrap();
+        p.add(1, 1);
+        assert_eq!(p.cap(), 9);
+    }
+
+    #[test]
+    fn test_policy_update() {
+        let p = LFUPolicy::new(100, 10).unwrap();
+        p.add(1, 1);
+        p.update(&1, 2);
+        let inner = p.inner.lock();
+        assert_eq!(inner.costs.key_costs.get(&1).unwrap(), &2);
+    }
+
+    #[test]
+    fn test_policy_cost() {
+        let p = LFUPolicy::new(100, 10).unwrap();
+        p.add(1, 2);
+        assert_eq!(p.cost(&1), 2);
+        assert_eq!(p.cost(&2), -1);
+    }
+
+    #[test]
+    fn test_policy_clear() {
+        let p = LFUPolicy::new(100, 10).unwrap();
+        p.add(1, 1);
+        p.add(2, 2);
+        p.add(3, 3);
+        p.clear();
+
+        assert_eq!(p.cap(), 10);
+        assert!(!p.contains(&2));
+        assert!(!p.contains(&2));
+        assert!(!p.contains(&3));
+    }
+
+    #[test]
+    fn test_policy_close() {
+        let p = LFUPolicy::new(100, 10).unwrap();
+        p.add(1, 1);
+        let _ = p.close();
+        sleep(WAIT);
+        assert!(p.items_tx.send(vec![1]).is_err())
+    }
+
+    #[test]
+    fn test_policy_push_after_close() {
+        let p = LFUPolicy::new(100, 10).unwrap();
+        let _ = p.close();
+        assert!(!p.push(vec![1, 2]).unwrap());
+    }
+
+    #[test]
+    fn test_policy_add_after_close() {
+        let p = LFUPolicy::new(100, 10).unwrap();
+        let _ = p.close();
+        p.add(1, 1);
+    }
 }
 
 #[cfg(feature = "async")]