diff --git a/contracts/main.fc b/contracts/main.fc
index bbe70ee..40ceb53 100644
--- a/contracts/main.fc
+++ b/contracts/main.fc
@@ -21,7 +21,7 @@
 
 ;; message binary format is defined as TL-B in companion .tlb file
 
-() op_withdraw(int withdraw_amount, slice owner_address);
+() op_withdraw(int withdraw_amount, slice owner_address) impure;
 
 () recv_internal(int msg_value, cell in_msg, slice in_msg_body) impure {
   ;; parse incoming internal message
@@ -48,6 +48,7 @@
 
   if (op == op::deposit()) {
     ;; empty since ton received (msg_value) is added automatically to contract balance
+    ;; ~dump msg_value; ;; an example of debug output, requires running contract in debug mode
     return ();
   }
   
@@ -68,7 +69,7 @@
   throw(error::unknown_op());
 }
 
-() op_withdraw(int withdraw_amount, slice owner_address) {
+() op_withdraw(int withdraw_amount, slice owner_address) impure {
   var [balance, _] = get_balance();
   throw_unless(error::insufficient_balance(), balance >= withdraw_amount);
   int return_value = min(withdraw_amount, balance - const::min_tons_for_storage());
diff --git a/contracts/main.ts b/contracts/main.ts
index 4d63119..c1eac59 100644
--- a/contracts/main.ts
+++ b/contracts/main.ts
@@ -1,3 +1,4 @@
+import BN from "bn.js";
 import { Cell, beginCell, Address } from "ton";
 
 // encode contract storage according to save_data() contract method
@@ -11,6 +12,14 @@ export function increment(): Cell {
   return beginCell().storeUint(0x37491f2f, 32).storeUint(0, 64).endCell();
 }
 
+export function deposit(): Cell {
+  return beginCell().storeUint(0x47d54391, 32).storeUint(0, 64).endCell();
+}
+
+export function withdraw(params: { withdrawAmount: BN }): Cell {
+  return beginCell().storeUint(0x41836980, 32).storeUint(0, 64).storeCoins(params.withdrawAmount).endCell();
+}
+
 export function transferOwnership(params: { newOwnerAddress: Address }): Cell {
   return beginCell().storeUint(0x2da38aaf, 32).storeUint(0, 64).storeAddress(params.newOwnerAddress).endCell();
 }
diff --git a/test/deposit.spec.ts b/test/deposit.spec.ts
new file mode 100644
index 0000000..b682c08
--- /dev/null
+++ b/test/deposit.spec.ts
@@ -0,0 +1,84 @@
+import chai, { expect } from "chai";
+import chaiBN from "chai-bn";
+import BN from "bn.js";
+chai.use(chaiBN(BN));
+
+import * as fs from "fs";
+import { Cell, toNano } from "ton";
+import { SmartContract } from "ton-contract-executor";
+import * as main from "../contracts/main";
+import { internalMessage, randomAddress, setBalance } from "./helpers";
+
+describe("Deposit and withdraw tests", () => {
+  let contract: SmartContract;
+
+  beforeEach(async () => {
+    contract = await SmartContract.fromCell(
+      Cell.fromBoc(fs.readFileSync("build/main.cell"))[0], // code cell from build output
+      main.data({
+        ownerAddress: randomAddress("owner"),
+        counter: 17,
+      })
+    );
+  });
+
+  it("should get balance", async () => {
+    setBalance(contract, toNano(37));
+    const call = await contract.invokeGetMethod("balance", []);
+    expect(call.result[0]).to.be.bignumber.equal(toNano(37));
+  });
+
+  it("should allow the owner to withdraw when balance is high", async () => {
+    setBalance(contract, toNano(37));
+    const send = await contract.sendInternalMessage(
+      internalMessage({
+        from: randomAddress("owner"),
+        body: main.withdraw({ withdrawAmount: toNano(20) }),
+      })
+    );
+    expect(send.type).to.equal("success");
+    expect(send.actionList).to.have.lengthOf(1);
+    const resultMessage = (send.actionList[0] as any)?.message?.info;
+    expect(resultMessage?.dest?.equals(randomAddress("owner"))).to.equal(true);
+    expect(resultMessage?.value?.coins).to.be.bignumber.equal(toNano(20));
+  });
+
+  it("should prevent others from withdrawing when balance is high", async () => {
+    setBalance(contract, toNano(37));
+    const send = await contract.sendInternalMessage(
+      internalMessage({
+        from: randomAddress("notowner"),
+        body: main.withdraw({ withdrawAmount: toNano(20) }),
+      })
+    );
+    expect(send.type).to.equal("failed");
+    expect(send.exit_code).to.equal(102); // access_denied in contracts/imports/constants.fc
+  });
+
+  it("should prevent the owner to withdraw when balance is low", async () => {
+    setBalance(contract, toNano(10));
+    const send = await contract.sendInternalMessage(
+      internalMessage({
+        from: randomAddress("owner"),
+        body: main.withdraw({ withdrawAmount: toNano(20) }),
+      })
+    );
+    expect(send.type).to.equal("failed");
+    expect(send.exit_code).to.equal(103); // insufficient_balance in contracts/imports/constants.fc
+  });
+
+  it("should leave enough balance for rent", async () => {
+    setBalance(contract, toNano(20));
+    const send = await contract.sendInternalMessage(
+      internalMessage({
+        from: randomAddress("owner"),
+        body: main.withdraw({ withdrawAmount: toNano(20) }),
+      })
+    );
+    expect(send.type).to.equal("success");
+    expect(send.actionList).to.have.lengthOf(1);
+    const resultMessage = (send.actionList[0] as any)?.message?.info;
+    expect(resultMessage?.dest?.equals(randomAddress("owner"))).to.equal(true);
+    expect(resultMessage?.value?.coins).to.be.bignumber.equal(toNano(20).sub(toNano(0.01))); // min_tons_for_storage in contracts/imports/constants.fc
+  });
+});
diff --git a/test/helpers.ts b/test/helpers.ts
index 6f58397..d57397f 100644
--- a/test/helpers.ts
+++ b/test/helpers.ts
@@ -1,5 +1,6 @@
 import BN from "bn.js";
 import { Address, Cell, CellMessage, InternalMessage, CommonMessageInfo } from "ton";
+import { SmartContract } from "ton-contract-executor";
 import Prando from "prando";
 
 export const zeroAddress = new Address(0, Buffer.alloc(32, 0));
@@ -23,3 +24,10 @@ export function internalMessage(params: { from?: Address; to?: Address; value?:
     body: new CommonMessageInfo({ body: message }),
   });
 }
+
+// temp fix until ton-contract-executor remembers c7 value between calls
+export function setBalance(contract: SmartContract, balance: BN) {
+  contract.setC7Config({
+    balance: balance.toNumber(),
+  });
+}