diff --git a/Cargo.lock b/Cargo.lock
index 4ab76f1..5608d99 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1670,6 +1670,28 @@ dependencies = [
  "url",
 ]
 
+[[package]]
+name = "serial_test"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b15f74add9a9d4a3eb2bf739c9a427d266d3895b53d992c3a7c234fec2ff1f1"
+dependencies = [
+ "lazy_static",
+ "parking_lot",
+ "serial_test_derive",
+]
+
+[[package]]
+name = "serial_test_derive"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "65f59259be9fc1bf677d06cc1456e97756004a1a5a577480f71430bd7c17ba33"
+dependencies = [
+ "proc-macro2 1.0.19",
+ "quote 1.0.7",
+ "syn 1.0.35",
+]
+
 [[package]]
 name = "shlex"
 version = "0.1.1"
@@ -1844,6 +1866,7 @@ dependencies = [
  "regex",
  "serde",
  "serde_derive",
+ "serial_test",
  "simple_logger",
  "tempdir",
  "tikv-client-common",
diff --git a/Cargo.toml b/Cargo.toml
index 58147cf..0091507 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -51,6 +51,7 @@ proptest = "0.9"
 proptest-derive = "0.1.0"
 fail = { version = "0.3", features = [ "failpoints" ] }
 simple_logger = "1.9.0"
+serial_test = "0.5.0"
 
 [patch.crates-io]
 raft-proto = { git = "https://github.com/tikv/raft-rs", rev = "e624c1d48460940a40d8aa69b5329460d9af87dd" }
diff --git a/tests/integration_tests.rs b/tests/integration_tests.rs
index 05f5f7b..9c7b412 100644
--- a/tests/integration_tests.rs
+++ b/tests/integration_tests.rs
@@ -2,12 +2,61 @@
 
 use failure::Fallible;
 use futures::prelude::*;
-use std::{collections::HashMap, env};
-use tikv_client::{Config, Key, Result, TransactionClient, Value};
+use rand::{seq::IteratorRandom, thread_rng, Rng};
+use serial_test::serial;
+use std::{
+    collections::{HashMap, HashSet},
+    convert::TryInto,
+    env,
+};
+use tikv_client::{Config, Key, RawClient, Result, Transaction, TransactionClient, Value};
+
+/// The limit of scan in each iteration in `clear_tikv`.
+const SCAN_BATCH_SIZE: u32 = 1000;
+
+// Parameters used in test
+const NUM_PEOPLE: u32 = 100;
+const NUM_TRNASFER: u32 = 100;
+
+/// Delete all entris in TiKV to leave a clean space for following tests.
+/// TiKV does not provide an elegant way to do this, so it is done by scanning and deletions.
+async fn clear_tikv() -> Fallible<()> {
+    delete_all_raw().await?;
+    delete_all_txn().await?;
+    Fallible::Ok(())
+}
+
+async fn delete_all_raw() -> Fallible<()> {
+    let config = Config::new(pd_addrs());
+    let raw_client = RawClient::new(config).await?.with_key_only(true);
+    raw_client.delete_range(vec![]..).await?;
+    Fallible::Ok(())
+}
+
+async fn delete_all_txn() -> Fallible<()> {
+    let config = Config::new(pd_addrs());
+    let txn_client = TransactionClient::new(config).await?;
+    let mut txn = txn_client.begin().await?;
+
+    loop {
+        let mut keys = txn.scan(vec![].., SCAN_BATCH_SIZE, true).await?.peekable();
+
+        if keys.peek().is_none() {
+            break;
+        }
+
+        for kv in keys {
+            txn.delete(kv.into_key()).await?;
+        }
+    }
+
+    txn.commit().await?;
+    Fallible::Ok(())
+}
 
 #[tokio::test]
 async fn get_timestamp() -> Fallible<()> {
-    const COUNT: usize = 1 << 16;
+    const COUNT: usize = 1 << 8; // use a small number to make test fast
     let config = Config::new(pd_addrs());
     let client = TransactionClient::new(config).await?;
 
@@ -25,7 +74,9 @@ async fn get_timestamp() -> Fallible<()> {
 }
 
 #[tokio::test]
+#[serial]
 async fn crud() -> Fallible<()> {
+    clear_tikv().await?;
     let config = Config::new(pd_addrs());
 
     let client = TransactionClient::new(config).await?;
@@ -100,6 +151,258 @@ async fn crud() -> Fallible<()> {
     Fallible::Ok(())
 }
 
+/// bank transfer mainly tests raw put and get
+#[tokio::test]
+#[serial]
+async fn raw_bank_transfer() -> Fallible<()> {
+    clear_tikv().await?;
+    let config = Config::new(pd_addrs());
+    let client = RawClient::new(config).await?;
+    let mut rng = thread_rng();
+
+    let people = gen_u32_keys(NUM_PEOPLE, &mut rng);
+    let mut sum: u32 = 0;
+    for person in &people {
+        let init = rng.gen::<u8>() as u32;
+        sum += init as u32;
+        client
+            .put(person.clone(), init.to_be_bytes().to_vec())
+            .await?;
+    }
+
+    // transfer
+    for _ in 0..NUM_TRNASFER {
+        let chosen_people = people.iter().choose_multiple(&mut rng, 2);
+        let alice = chosen_people[0];
+        let mut alice_balance = get_u32(&client, alice.clone()).await?;
+        let bob = chosen_people[1];
+        let mut bob_balance = get_u32(&client, bob.clone()).await?;
+        let transfer = rng.gen_range(0, alice_balance);
+        alice_balance -= transfer;
+        bob_balance += transfer;
+        client
+            .put(alice.clone(), alice_balance.to_be_bytes().to_vec())
+            .await?;
+        client
+            .put(bob.clone(), bob_balance.to_be_bytes().to_vec())
+            .await?;
+    }
+
+    // check
+    let mut new_sum = 0;
+    for person in &people {
+        new_sum += get_u32(&client, person.clone()).await?;
+    }
+    assert_eq!(sum, new_sum);
+    Fallible::Ok(())
+}
+
+#[tokio::test]
+#[serial]
+async fn txn_bank_transfer() -> Fallible<()> {
+    clear_tikv().await?;
+    let config = Config::new(pd_addrs());
+    let client = TransactionClient::new(config).await?;
+    let mut rng = thread_rng();
+
+    let people = gen_u32_keys(NUM_PEOPLE, &mut rng);
+    let mut txn = client.begin().await?;
+    let mut sum: u32 = 0;
+    for person in &people {
+        let init = rng.gen::<u8>() as u32;
+        sum += init as u32;
+        txn.set(person.clone(), init.to_be_bytes().to_vec()).await?;
+    }
+    txn.commit().await?;
+
+    // transfer
+    for _ in 0..NUM_TRNASFER {
+        let mut txn = client.begin().await?;
+        let chosen_people = people.iter().choose_multiple(&mut rng, 2);
+        let alice = chosen_people[0];
+        let mut alice_balance = get_txn_u32(&txn, alice.clone()).await?;
+        let bob = chosen_people[1];
+        let mut bob_balance = get_txn_u32(&txn, bob.clone()).await?;
+        let transfer = rng.gen_range(0, alice_balance);
+        alice_balance -= transfer;
+        bob_balance += transfer;
+        txn.set(alice.clone(), alice_balance.to_be_bytes().to_vec())
+            .await?;
+        txn.set(bob.clone(), bob_balance.to_be_bytes().to_vec())
+            .await?;
+        txn.commit().await?;
+    }
+
+    // check
+    let mut new_sum = 0;
+    let mut txn = client.begin().await?;
+    for person in people.iter() {
+        new_sum += get_txn_u32(&txn, person.clone()).await?;
+    }
+    assert_eq!(sum, new_sum);
+    txn.commit().await?;
+    Fallible::Ok(())
+}
+
+#[tokio::test]
+#[serial]
+async fn raw() -> Fallible<()> {
+    clear_tikv().await?;
+    let config = Config::new(pd_addrs());
+    let client = RawClient::new(config).await?;
+
+    // empty; get non-existent key
+    let res = client.get("k1".to_owned()).await;
+    assert_eq!(res?, None);
+
+    // empty; put then batch_get
+    client.put("k1".to_owned(), "v1".to_owned()).await?;
+    client.put("k2".to_owned(), "v2".to_owned()).await?;
+
+    let res = client
+        .batch_get(vec!["k1".to_owned(), "k2".to_owned(), "k3".to_owned()])
+        .await?;
+    assert_eq!(res.len(), 2);
+    assert_eq!(res[0].1, "v1".as_bytes());
+    assert_eq!(res[1].1, "v2".as_bytes());
+
+    // k1,k2; batch_put then batch_get
+    let _ = client
+        .batch_put(vec![
+            ("k3".to_owned(), "v3".to_owned()),
+            ("k4".to_owned(), "v4".to_owned()),
+        ])
+        .await?;
+
+    let res = client
+        .batch_get(vec!["k4".to_owned(), "k3".to_owned()])
+        .await?;
+    assert_eq!(res[0].1, "v4".as_bytes());
+    assert_eq!(res[1].1, "v3".as_bytes());
+
+    // k1,k2,k3,k4; delete then get
+    let res = client.delete("k3".to_owned()).await;
+    assert!(res.is_ok());
+
+    let res = client.get("k3".to_owned()).await?;
+    assert_eq!(res, None);
+
+    // k1,k2,k4; batch_delete then batch_get
+    let res = client
+        .batch_delete(vec![
+            "k1".to_owned(),
+            "k2".to_owned(),
+            "k3".to_owned(),
+            "k4".to_owned(),
+        ])
+        .await;
+    assert!(res.is_ok());
+
+    let res = client
+        .batch_get(vec![
+            "k1".to_owned(),
+            "k2".to_owned(),
+            "k3".to_owned(),
+            "k4".to_owned(),
+        ])
+        .await?;
+    assert_eq!(res.len(), 0);
+
+    // empty; batch_put then scan
+    let _ = client
+        .batch_put(vec![
+            ("k3".to_owned(), "v3".to_owned()),
+            ("k5".to_owned(), "v5".to_owned()),
+            ("k1".to_owned(), "v1".to_owned()),
+            ("k2".to_owned(), "v2".to_owned()),
+            ("k4".to_owned(), "v4".to_owned()),
+        ])
+        .await?;
+
+    let res = client.scan("k2".to_owned()..="k5".to_owned(), 5).await?;
+    assert_eq!(res.len(), 4);
+    assert_eq!(res[0].1, "v2".as_bytes());
+    assert_eq!(res[1].1, "v3".as_bytes());
+    assert_eq!(res[2].1, "v4".as_bytes());
+    assert_eq!(res[3].1, "v5".as_bytes());
+
+    let res = client.scan("k2".to_owned().."k5".to_owned(), 2).await?;
+    assert_eq!(res.len(), 2);
+    assert_eq!(res[0].1, "v2".as_bytes());
+    assert_eq!(res[1].1, "v3".as_bytes());
+
+    let res = client.scan("k1".to_owned().., 20).await?;
+    assert_eq!(res.len(), 5);
+    assert_eq!(res[0].1, "v1".as_bytes());
+    assert_eq!(res[1].1, "v2".as_bytes());
+    assert_eq!(res[2].1, "v3".as_bytes());
+    assert_eq!(res[3].1, "v4".as_bytes());
+    assert_eq!(res[4].1, "v5".as_bytes());
+
+    let res = client
+        .batch_scan(
+            vec![
+                "".to_owned().."k1".to_owned(),
+                "k1".to_owned().."k2".to_owned(),
+                "k2".to_owned().."k3".to_owned(),
+                "k3".to_owned().."k4".to_owned(),
+                "k4".to_owned().."k5".to_owned(),
+            ],
+            2,
+        )
+        .await?;
+    assert_eq!(res.len(), 4);
+
+    let res = client
+        .batch_scan(
+            vec![
+                "".to_owned()..="k3".to_owned(),
+                "k2".to_owned()..="k5".to_owned(),
+            ],
+            4,
+        )
+        .await?;
+    assert_eq!(res.len(), 7);
+    assert_eq!(res[0].1, "v1".as_bytes());
+    assert_eq!(res[1].1, "v2".as_bytes());
+    assert_eq!(res[2].1, "v3".as_bytes());
+    assert_eq!(res[3].1, "v2".as_bytes());
+    assert_eq!(res[4].1, "v3".as_bytes());
+    assert_eq!(res[5].1, "v4".as_bytes());
+    assert_eq!(res[6].1, "v5".as_bytes());
+
+    Fallible::Ok(())
+}
+
+// helper function
+async fn get_u32(client: &RawClient, key: Vec<u8>) -> Fallible<u32> {
+    let x = client.get(key).await?.unwrap();
+    let boxed_slice = x.into_boxed_slice();
+    let array: Box<[u8; 4]> = boxed_slice
+        .try_into()
+        .expect("Value should not exceed u32 (4 * u8)");
+    Fallible::Ok(u32::from_be_bytes(*array))
+}
+
+// helper function
+async fn get_txn_u32(txn: &Transaction, key: Vec<u8>) -> Fallible<u32> {
+    let x = txn.get(key).await?.unwrap();
+    let boxed_slice = x.into_boxed_slice();
+    let array: Box<[u8; 4]> = boxed_slice
+        .try_into()
+        .expect("Value should not exceed u32 (4 * u8)");
+    Fallible::Ok(u32::from_be_bytes(*array))
+}
+
+// helper function
+fn gen_u32_keys(num: u32, rng: &mut impl Rng) -> HashSet<Vec<u8>> {
+    let mut set = HashSet::new();
+    for _ in 0..num {
+        set.insert(rng.gen::<u32>().to_be_bytes().to_vec());
+    }
+    set
+}
+
 const ENV_PD_ADDRS: &str = "PD_ADDRS";
 
 fn pd_addrs() -> Vec<String> {