Refactor Leader class and add new test case

Makefile

@@ -5,7 +5,7 @@ lint:
 @PHONY: lint
 
 test:
-	npx jest tests/*.js
+	npx jest --detectOpenHandles tests/*.js
 @PHONY: test
 
 upgrade:

index.js

@@ -10,14 +10,14 @@ class Leader extends EventEmitter {
     this.options = {}
     this.options.ttl = Math.max(options.ttl || 0, 1000) // Lock time to live
     this.options.wait = Math.max(options.wait || 0, 100) // Time between tries to be elected
-    this.key =
-      'leader-' +
-      crypto
-        .createHash('sha1')
-        .update(options.key || 'default')
-        .digest('hex')
+    this.stopped = false // Flag to stop the leader election
 
-    this.initDatabase().then(() => this.elect())
+    const hash = crypto
+      .createHash('sha1')
+      .update(options.key || 'default')
+      .digest('hex')
+
+    this.key = `leader-${hash}`
   }
 
   initDatabase() {
@@ -56,6 +56,7 @@ class Leader extends EventEmitter {
   }
 
   elect() {
+    if (this.stopped) return
     this.db
       .collection(this.key)
       .findOneAndUpdate(
@@ -74,6 +75,7 @@ class Leader extends EventEmitter {
   }
 
   renew() {
+    if (this.stopped) return
     this.db
       .collection(this.key)
       .findOneAndUpdate(
@@ -90,6 +92,15 @@ class Leader extends EventEmitter {
         }
       })
   }
+
+  stop() {
+    this.stopped = true
+  }
+
+  start() {
+    this.stopped = false
+    this.initDatabase().then(() => this.elect())
+  }
 }
 
 module.exports = { Leader }

package.json

@@ -26,6 +26,7 @@
   },
   "homepage": "https://github.com/andrewmolyuk/mongo-leader#readme",
   "devDependencies": {
+    "@jest/globals": "^29.7.0",
     "eslint": "^8.57.0",
     "eslint-config-standard": "^17.1.0",
     "eslint-plugin-import": "^2.29.1",

tests/index.test.js

@@ -1,13 +1,22 @@
 'use strict'
 
-const assert = require('assert')
+const { describe, it, expect, afterEach } = require('@jest/globals')
 
-describe('Your Test Suite', () => {
-  it('should test something', () => {
-    // Your test code here
-  })
+const { Leader } = require('../index')
+const { mockDb } = require('./mockDb')
+
+describe('Leader', () => {
+  describe('constructor', () => {
+    it('should set default options', function () {
+      // Act
+      const leader = new Leader(mockDb)
 
-  it('should test something else', () => {
-    // Your test code here
+      // Assert
+      expect(leader.db).toBe(mockDb)
+      expect(leader.options).not.toBeNull()
+      expect(leader.options.ttl).toBe(1000)
+      expect(leader.options.wait).toBe(100)
+      expect(leader.key).toMatch(/^leader-?/)
+    })
   })
 })

tests/mockDb.js

@@ -0,0 +1,32 @@
+'use strict'
+
+const mockAdmin = {
+  command: () => Promise.resolve(),
+}
+
+const mockDb = {
+  command: () => Promise.resolve({}),
+  admin: () => mockAdmin,
+  listCollections() {
+    return {
+      hasNext() {
+        return Promise.resolve(false)
+      },
+    }
+  },
+  collection(key) {
+    return {
+      createIndex() {
+        return Promise.resolve()
+      },
+      findOneAndUpdate() {
+        return Promise.resolve()
+      },
+    }
+  },
+  createCollection() {
+    return Promise.resolve()
+  },
+}
+
+module.exports = { mockAdmin, mockDb }