diff --git a/.gitignore b/.gitignore
index 10886dc0..c5077bd0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -30,3 +30,4 @@ coverage
 data
 redis.conf
 dump.rdb
+.envrc
diff --git a/package.json b/package.json
index d2f3e897..5aac9560 100644
--- a/package.json
+++ b/package.json
@@ -35,6 +35,7 @@
     "@fastify/sensible": "^5.5.0",
     "@fastify/swagger": "^8.14.0",
     "@fastify/swagger-ui": "^3.0.0",
+    "@nervosnetwork/ckb-sdk-utils": "^0.109.1",
     "@rgbpp-sdk/btc": "0.0.0-snap-20240321073744",
     "@rgbpp-sdk/ckb": "0.0.0-snap-20240321073744",
     "@sentry/node": "^7.102.1",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 44d0911a..fe7089b5 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -41,6 +41,9 @@ dependencies:
   '@fastify/swagger-ui':
     specifier: ^3.0.0
     version: 3.0.0
+  '@nervosnetwork/ckb-sdk-utils':
+    specifier: ^0.109.1
+    version: 0.109.1
   '@rgbpp-sdk/btc':
     specifier: 0.0.0-snap-20240321073744
     version: 0.0.0-snap-20240321073744
diff --git a/src/services/unlocker.ts b/src/services/unlocker.ts
index 5c00b5db..41f877dd 100644
--- a/src/services/unlocker.ts
+++ b/src/services/unlocker.ts
@@ -41,7 +41,7 @@ export default class Unlocker implements IUnlocker {
   /**
    * Get next batch of BTC time lock cells
    */
-  private async getNextBatchLockCell() {
+  public async getNextBatchLockCell() {
     const collect = this.collector.collect();
     const cells: IndexerCell[] = [];
 
diff --git a/test/services/unlocker.test.ts b/test/services/unlocker.test.ts
new file mode 100644
index 00000000..bef15347
--- /dev/null
+++ b/test/services/unlocker.test.ts
@@ -0,0 +1,94 @@
+/* eslint-disable @typescript-eslint/ban-ts-comment */
+import container from '../../src/container';
+import { describe, test, beforeEach, vi, expect, afterEach } from 'vitest';
+import Unlocker from '../../src/services/unlocker';
+import { Cell } from '@ckb-lumos/lumos';
+import { BTCTimeLock, genBtcTimeLockScript } from '@rgbpp-sdk/ckb';
+
+describe('Unlocker', () => {
+  let unlocker: Unlocker;
+
+  beforeEach(async () => {
+    const cradle = container.cradle;
+    // TODO: mock env.TRANSACTION_SPV_SERVICE_URL
+    unlocker = new Unlocker(cradle);
+  });
+
+  afterEach(() => {
+    vi.unstubAllEnvs();
+  });
+
+  function mockBtcTimeLockCell() {
+    vi.spyOn(BTCTimeLock, 'unpack').mockReturnValue({
+      after: 6,
+      btcTxid: '0x12345',
+      lockScript: {} as unknown as CKBComponents.Script,
+    });
+    vi.spyOn(unlocker['collector'], 'collect').mockImplementation(async function* () {
+      const toLock: CKBComponents.Script = {
+        args: '0xc0a45d9d7c024adcc8076c18b3f07c08de7c42120cdb7e6cbc05a28266b15b5f',
+        codeHash: '0x28e83a1277d48add8e72fadaa9248559e1b632bab2bd60b27955ebc4c03800a5',
+        hashType: 'data',
+      };
+      yield {
+        blockNumber: '0x123',
+        outPoint: {
+          txHash: '0x',
+          index: '0x0',
+        },
+        cellOutput: {
+          lock: genBtcTimeLockScript(toLock, false),
+          capacity: '0x123',
+        },
+        data: '0x',
+      } as Cell;
+      yield {
+        blockNumber: '0x456',
+        outPoint: {
+          txHash: '0x',
+          index: '0x0',
+        },
+        cellOutput: {
+          lock: genBtcTimeLockScript(toLock, false),
+          capacity: '0x456',
+        },
+        data: '0x',
+      } as Cell;
+    });
+  }
+
+  test('getNextBatchLockCell: should skip unconfirmed btc tx', async () => {
+    // @ts-expect-error
+    vi.spyOn(unlocker['cradle'].bitcoind, 'getBlockchainInfo').mockResolvedValue({ blocks: 100 });
+    // @ts-expect-error
+    vi.spyOn(unlocker['cradle'].bitcoind, 'getTransaction').mockResolvedValue({ blockheight: 95 });
+    mockBtcTimeLockCell();
+
+    const cells = await unlocker.getNextBatchLockCell();
+    expect(cells).toHaveLength(0);
+  });
+
+  test('getNextBatchLockCell: should return cells when btc tx is confirmed', async () => {
+    // @ts-expect-error
+    vi.spyOn(unlocker['cradle'].bitcoind, 'getBlockchainInfo').mockResolvedValue({ blocks: 101 });
+    // @ts-expect-error
+    vi.spyOn(unlocker['cradle'].bitcoind, 'getTransaction').mockResolvedValue({ blockheight: 95 });
+    mockBtcTimeLockCell();
+
+    const cells = await unlocker.getNextBatchLockCell();
+    expect(cells).toHaveLength(2);
+  });
+
+  test('getNextBatchLockCell: should break when cells reach batch size', async () => {
+    unlocker['cradle'].env.UNLOCKER_CELL_BATCH_SIZE = 1;
+
+    // @ts-expect-error
+    vi.spyOn(unlocker['cradle'].bitcoind, 'getBlockchainInfo').mockResolvedValue({ blocks: 101 });
+    // @ts-expect-error
+    vi.spyOn(unlocker['cradle'].bitcoind, 'getTransaction').mockResolvedValue({ blockheight: 95 });
+    mockBtcTimeLockCell();
+
+    const cells = await unlocker.getNextBatchLockCell();
+    expect(cells).toHaveLength(1);
+  });
+});