diff --git a/src/region_cache.rs b/src/region_cache.rs
index a9eb4531..df224d92 100644
--- a/src/region_cache.rs
+++ b/src/region_cache.rs
@@ -497,11 +497,15 @@ mod test {
     async fn test_get_region_by_key() -> Result<()> {
         let retry_client = Arc::new(MockRetryClient::default());
         let cache = RegionCache::new(retry_client.clone());
+        let leader = Some(metapb::Peer {
+            store_id: 1,
+            ..Default::default()
+        });
 
-        let region1 = region(1, vec![], vec![10]);
-        let region2 = region(2, vec![10], vec![20]);
+        let region1 = region_with_leader(1, vec![], vec![10], leader.clone());
+        let region2 = region_with_leader(2, vec![10], vec![20], leader.clone());
         let region3 = region(3, vec![30], vec![40]);
-        let region4 = region(4, vec![50], vec![]);
+        let region4 = region_with_leader(4, vec![50], vec![], leader.clone());
         cache.add_region(region1.clone()).await;
         cache.add_region(region2.clone()).await;
         cache.add_region(region3.clone()).await;
@@ -521,6 +525,8 @@ mod test {
         );
         assert!(cache.get_region_by_key(&vec![20].into()).await.is_err());
         assert!(cache.get_region_by_key(&vec![25].into()).await.is_err());
+        // region3 in cache has no leader, the cache is invalid.
+        assert!(cache.get_region_by_key(&vec![35].into()).await.is_err());
         assert_eq!(cache.get_region_by_key(&vec![60].into()).await?, region4);
         Ok(())
     }
@@ -557,6 +563,26 @@ mod test {
         region
     }
 
+    fn region_with_leader(
+        id: RegionId,
+        start_key: Vec<u8>,
+        end_key: Vec<u8>,
+        leader: Option<metapb::Peer>,
+    ) -> RegionWithLeader {
+        let mut region = RegionWithLeader::default();
+        region.region.id = id;
+        region.region.start_key = start_key;
+        region.region.end_key = end_key;
+        region.region.region_epoch = Some(RegionEpoch {
+            conf_ver: 0,
+            version: 0,
+        });
+        // We don't care about other fields here
+
+        region.leader = leader;
+        region
+    }
+
     #[test]
     fn test_is_valid_tikv_store() {
         let mut store = metapb::Store::default();