fix: fix task stealing related options handling at runtime
[poolifier.git] / tests / pools / abstract / abstract-pool.test.js
index 03bcce050f35a2f8907f0974ddf8c1c8c828937d..aeede25d7149a9c5918626ae9e860e7733cea4b4 100644 (file)
@@ -1,3 +1,4 @@
+const { EventEmitter } = require('node:events')
 const { expect } = require('expect')
 const sinon = require('sinon')
 const {
@@ -11,9 +12,11 @@ const {
   WorkerTypes
 } = require('../../../lib')
 const { CircularArray } = require('../../../lib/circular-array')
-const { Queue } = require('../../../lib/queue')
+const { Deque } = require('../../../lib/deque')
+const { DEFAULT_TASK_NAME } = require('../../../lib/utils')
 const { version } = require('../../../package.json')
 const { waitPoolEvents } = require('../../test-utils')
+const { WorkerNode } = require('../../../lib/pools/worker-node')
 
 describe('Abstract pool test suite', () => {
   const numberOfWorkers = 2
@@ -23,6 +26,10 @@ describe('Abstract pool test suite', () => {
     }
   }
 
+  afterEach(() => {
+    sinon.restore()
+  })
+
   it('Simulate pool creation from a non main thread/process', () => {
     expect(
       () =>
@@ -30,14 +37,26 @@ describe('Abstract pool test suite', () => {
           numberOfWorkers,
           './tests/worker-files/thread/testWorker.js',
           {
-            errorHandler: (e) => console.error(e)
+            errorHandler: e => console.error(e)
           }
         )
     ).toThrowError(
-      'Cannot start a pool from a worker with the same type as the pool'
+      new Error(
+        'Cannot start a pool from a worker with the same type as the pool'
+      )
     )
   })
 
+  it('Verify that pool statuses properties are set', async () => {
+    const pool = new FixedThreadPool(
+      numberOfWorkers,
+      './tests/worker-files/thread/testWorker.js'
+    )
+    expect(pool.starting).toBe(false)
+    expect(pool.started).toBe(true)
+    await pool.destroy()
+  })
+
   it('Verify that filePath is checked', () => {
     const expectedError = new Error(
       'Please specify a file with a worker implementation'
@@ -61,7 +80,9 @@ describe('Abstract pool test suite', () => {
 
   it('Verify that numberOfWorkers is checked', () => {
     expect(() => new FixedThreadPool()).toThrowError(
-      'Cannot instantiate a pool without specifying the number of workers'
+      new Error(
+        'Cannot instantiate a pool without specifying the number of workers'
+      )
     )
   })
 
@@ -134,22 +155,22 @@ describe('Abstract pool test suite', () => {
     )
     expect(
       () =>
-        new DynamicClusterPool(
-          1,
-          1,
-          './tests/worker-files/cluster/testWorker.js'
-        )
+        new DynamicThreadPool(0, 0, './tests/worker-files/thread/testWorker.js')
     ).toThrowError(
       new RangeError(
-        'Cannot instantiate a dynamic pool with a minimum pool size equal to the maximum pool size. Use a fixed pool instead'
+        'Cannot instantiate a dynamic pool with a maximum pool size equal to zero'
       )
     )
     expect(
       () =>
-        new DynamicThreadPool(0, 0, './tests/worker-files/thread/testWorker.js')
+        new DynamicClusterPool(
+          1,
+          1,
+          './tests/worker-files/cluster/testWorker.js'
+        )
     ).toThrowError(
       new RangeError(
-        'Cannot instantiate a dynamic pool with a maximum pool size equal to zero'
+        'Cannot instantiate a dynamic pool with a minimum pool size equal to the maximum pool size. Use a fixed pool instead'
       )
     )
   })
@@ -159,30 +180,35 @@ describe('Abstract pool test suite', () => {
       numberOfWorkers,
       './tests/worker-files/thread/testWorker.js'
     )
-    expect(pool.emitter).toBeDefined()
-    expect(pool.opts.enableEvents).toBe(true)
-    expect(pool.opts.restartWorkerOnError).toBe(true)
-    expect(pool.opts.enableTasksQueue).toBe(false)
-    expect(pool.opts.tasksQueueOptions).toBeUndefined()
-    expect(pool.opts.workerChoiceStrategy).toBe(
-      WorkerChoiceStrategies.ROUND_ROBIN
-    )
-    expect(pool.opts.workerChoiceStrategyOptions).toStrictEqual({
-      choiceRetries: 6,
-      runTime: { median: false },
-      waitTime: { median: false },
-      elu: { median: false }
+    expect(pool.emitter).toBeInstanceOf(EventEmitter)
+    expect(pool.opts).toStrictEqual({
+      startWorkers: true,
+      enableEvents: true,
+      restartWorkerOnError: true,
+      enableTasksQueue: false,
+      workerChoiceStrategy: WorkerChoiceStrategies.ROUND_ROBIN,
+      workerChoiceStrategyOptions: {
+        retries: 6,
+        runTime: { median: false },
+        waitTime: { median: false },
+        elu: { median: false }
+      }
     })
     expect(pool.workerChoiceStrategyContext.opts).toStrictEqual({
-      choiceRetries: 6,
+      retries: 6,
       runTime: { median: false },
       waitTime: { median: false },
       elu: { median: false }
     })
-    expect(pool.opts.messageHandler).toBeUndefined()
-    expect(pool.opts.errorHandler).toBeUndefined()
-    expect(pool.opts.onlineHandler).toBeUndefined()
-    expect(pool.opts.exitHandler).toBeUndefined()
+    for (const [, workerChoiceStrategy] of pool.workerChoiceStrategyContext
+      .workerChoiceStrategies) {
+      expect(workerChoiceStrategy.opts).toStrictEqual({
+        retries: 6,
+        runTime: { median: false },
+        waitTime: { median: false },
+        elu: { median: false }
+      })
+    }
     await pool.destroy()
     const testHandler = () => console.info('test handler executed')
     pool = new FixedThreadPool(
@@ -205,31 +231,47 @@ describe('Abstract pool test suite', () => {
       }
     )
     expect(pool.emitter).toBeUndefined()
-    expect(pool.opts.enableEvents).toBe(false)
-    expect(pool.opts.restartWorkerOnError).toBe(false)
-    expect(pool.opts.enableTasksQueue).toBe(true)
-    expect(pool.opts.tasksQueueOptions).toStrictEqual({ concurrency: 2 })
-    expect(pool.opts.workerChoiceStrategy).toBe(
-      WorkerChoiceStrategies.LEAST_USED
-    )
-    expect(pool.opts.workerChoiceStrategyOptions).toStrictEqual({
-      choiceRetries: 6,
-      runTime: { median: true },
-      waitTime: { median: false },
-      elu: { median: false },
-      weights: { 0: 300, 1: 200 }
+    expect(pool.opts).toStrictEqual({
+      startWorkers: true,
+      enableEvents: false,
+      restartWorkerOnError: false,
+      enableTasksQueue: true,
+      tasksQueueOptions: {
+        concurrency: 2,
+        size: 4,
+        taskStealing: true,
+        tasksStealingOnBackPressure: true
+      },
+      workerChoiceStrategy: WorkerChoiceStrategies.LEAST_USED,
+      workerChoiceStrategyOptions: {
+        retries: 6,
+        runTime: { median: true },
+        waitTime: { median: false },
+        elu: { median: false },
+        weights: { 0: 300, 1: 200 }
+      },
+      onlineHandler: testHandler,
+      messageHandler: testHandler,
+      errorHandler: testHandler,
+      exitHandler: testHandler
     })
     expect(pool.workerChoiceStrategyContext.opts).toStrictEqual({
-      choiceRetries: 6,
+      retries: 6,
       runTime: { median: true },
       waitTime: { median: false },
       elu: { median: false },
       weights: { 0: 300, 1: 200 }
     })
-    expect(pool.opts.messageHandler).toStrictEqual(testHandler)
-    expect(pool.opts.errorHandler).toStrictEqual(testHandler)
-    expect(pool.opts.onlineHandler).toStrictEqual(testHandler)
-    expect(pool.opts.exitHandler).toStrictEqual(testHandler)
+    for (const [, workerChoiceStrategy] of pool.workerChoiceStrategyContext
+      .workerChoiceStrategies) {
+      expect(workerChoiceStrategy.opts).toStrictEqual({
+        retries: 6,
+        runTime: { median: true },
+        waitTime: { median: false },
+        elu: { median: false },
+        weights: { 0: 300, 1: 200 }
+      })
+    }
     await pool.destroy()
   })
 
@@ -246,6 +288,38 @@ describe('Abstract pool test suite', () => {
     ).toThrowError(
       new Error("Invalid worker choice strategy 'invalidStrategy'")
     )
+    expect(
+      () =>
+        new FixedThreadPool(
+          numberOfWorkers,
+          './tests/worker-files/thread/testWorker.js',
+          {
+            workerChoiceStrategyOptions: {
+              retries: 'invalidChoiceRetries'
+            }
+          }
+        )
+    ).toThrowError(
+      new TypeError(
+        'Invalid worker choice strategy options: retries must be an integer'
+      )
+    )
+    expect(
+      () =>
+        new FixedThreadPool(
+          numberOfWorkers,
+          './tests/worker-files/thread/testWorker.js',
+          {
+            workerChoiceStrategyOptions: {
+              retries: -1
+            }
+          }
+        )
+    ).toThrowError(
+      new RangeError(
+        "Invalid worker choice strategy options: retries '-1' must be greater or equal than zero"
+      )
+    )
     expect(
       () =>
         new FixedThreadPool(
@@ -274,6 +348,19 @@ describe('Abstract pool test suite', () => {
         "Invalid worker choice strategy options: invalid measurement 'invalidMeasurement'"
       )
     )
+    expect(
+      () =>
+        new FixedThreadPool(
+          numberOfWorkers,
+          './tests/worker-files/thread/testWorker.js',
+          {
+            enableTasksQueue: true,
+            tasksQueueOptions: 'invalidTasksQueueOptions'
+          }
+        )
+    ).toThrowError(
+      new TypeError('Invalid tasks queue options: must be a plain object')
+    )
     expect(
       () =>
         new FixedThreadPool(
@@ -285,8 +372,8 @@ describe('Abstract pool test suite', () => {
           }
         )
     ).toThrowError(
-      new TypeError(
-        'Invalid worker tasks concurrency: 0 is a negative integer or zero'
+      new RangeError(
+        'Invalid worker node tasks concurrency: 0 is a negative integer or zero'
       )
     )
     expect(
@@ -296,11 +383,13 @@ describe('Abstract pool test suite', () => {
           './tests/worker-files/thread/testWorker.js',
           {
             enableTasksQueue: true,
-            tasksQueueOptions: 'invalidTasksQueueOptions'
+            tasksQueueOptions: { concurrency: -1 }
           }
         )
     ).toThrowError(
-      new TypeError('Invalid tasks queue options: must be a plain object')
+      new RangeError(
+        'Invalid worker node tasks concurrency: -1 is a negative integer or zero'
+      )
     )
     expect(
       () =>
@@ -313,7 +402,50 @@ describe('Abstract pool test suite', () => {
           }
         )
     ).toThrowError(
-      new TypeError('Invalid worker tasks concurrency: must be an integer')
+      new TypeError('Invalid worker node tasks concurrency: must be an integer')
+    )
+    expect(
+      () =>
+        new FixedThreadPool(
+          numberOfWorkers,
+          './tests/worker-files/thread/testWorker.js',
+          {
+            enableTasksQueue: true,
+            tasksQueueOptions: { size: 0 }
+          }
+        )
+    ).toThrowError(
+      new RangeError(
+        'Invalid worker node tasks queue size: 0 is a negative integer or zero'
+      )
+    )
+    expect(
+      () =>
+        new FixedThreadPool(
+          numberOfWorkers,
+          './tests/worker-files/thread/testWorker.js',
+          {
+            enableTasksQueue: true,
+            tasksQueueOptions: { size: -1 }
+          }
+        )
+    ).toThrowError(
+      new RangeError(
+        'Invalid worker node tasks queue size: -1 is a negative integer or zero'
+      )
+    )
+    expect(
+      () =>
+        new FixedThreadPool(
+          numberOfWorkers,
+          './tests/worker-files/thread/testWorker.js',
+          {
+            enableTasksQueue: true,
+            tasksQueueOptions: { size: 0.2 }
+          }
+        )
+    ).toThrowError(
+      new TypeError('Invalid worker node tasks queue size: must be an integer')
     )
   })
 
@@ -324,13 +456,13 @@ describe('Abstract pool test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.FAIR_SHARE }
     )
     expect(pool.opts.workerChoiceStrategyOptions).toStrictEqual({
-      choiceRetries: 6,
+      retries: 6,
       runTime: { median: false },
       waitTime: { median: false },
       elu: { median: false }
     })
     expect(pool.workerChoiceStrategyContext.opts).toStrictEqual({
-      choiceRetries: 6,
+      retries: 6,
       runTime: { median: false },
       waitTime: { median: false },
       elu: { median: false }
@@ -338,7 +470,7 @@ describe('Abstract pool test suite', () => {
     for (const [, workerChoiceStrategy] of pool.workerChoiceStrategyContext
       .workerChoiceStrategies) {
       expect(workerChoiceStrategy.opts).toStrictEqual({
-        choiceRetries: 6,
+        retries: 6,
         runTime: { median: false },
         waitTime: { median: false },
         elu: { median: false }
@@ -368,13 +500,13 @@ describe('Abstract pool test suite', () => {
       elu: { median: true }
     })
     expect(pool.opts.workerChoiceStrategyOptions).toStrictEqual({
-      choiceRetries: 6,
+      retries: 6,
       runTime: { median: true },
       waitTime: { median: false },
       elu: { median: true }
     })
     expect(pool.workerChoiceStrategyContext.opts).toStrictEqual({
-      choiceRetries: 6,
+      retries: 6,
       runTime: { median: true },
       waitTime: { median: false },
       elu: { median: true }
@@ -382,7 +514,7 @@ describe('Abstract pool test suite', () => {
     for (const [, workerChoiceStrategy] of pool.workerChoiceStrategyContext
       .workerChoiceStrategies) {
       expect(workerChoiceStrategy.opts).toStrictEqual({
-        choiceRetries: 6,
+        retries: 6,
         runTime: { median: true },
         waitTime: { median: false },
         elu: { median: true }
@@ -412,13 +544,13 @@ describe('Abstract pool test suite', () => {
       elu: { median: false }
     })
     expect(pool.opts.workerChoiceStrategyOptions).toStrictEqual({
-      choiceRetries: 6,
+      retries: 6,
       runTime: { median: false },
       waitTime: { median: false },
       elu: { median: false }
     })
     expect(pool.workerChoiceStrategyContext.opts).toStrictEqual({
-      choiceRetries: 6,
+      retries: 6,
       runTime: { median: false },
       waitTime: { median: false },
       elu: { median: false }
@@ -426,7 +558,7 @@ describe('Abstract pool test suite', () => {
     for (const [, workerChoiceStrategy] of pool.workerChoiceStrategyContext
       .workerChoiceStrategies) {
       expect(workerChoiceStrategy.opts).toStrictEqual({
-        choiceRetries: 6,
+        retries: 6,
         runTime: { median: false },
         waitTime: { median: false },
         elu: { median: false }
@@ -458,6 +590,22 @@ describe('Abstract pool test suite', () => {
         'Invalid worker choice strategy options: must be a plain object'
       )
     )
+    expect(() =>
+      pool.setWorkerChoiceStrategyOptions({
+        retries: 'invalidChoiceRetries'
+      })
+    ).toThrowError(
+      new TypeError(
+        'Invalid worker choice strategy options: retries must be an integer'
+      )
+    )
+    expect(() =>
+      pool.setWorkerChoiceStrategyOptions({ retries: -1 })
+    ).toThrowError(
+      new RangeError(
+        "Invalid worker choice strategy options: retries '-1' must be greater or equal than zero"
+      )
+    )
     expect(() =>
       pool.setWorkerChoiceStrategyOptions({ weights: {} })
     ).toThrowError(
@@ -482,15 +630,41 @@ describe('Abstract pool test suite', () => {
     )
     expect(pool.opts.enableTasksQueue).toBe(false)
     expect(pool.opts.tasksQueueOptions).toBeUndefined()
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.onEmptyQueue).toBeUndefined()
+      expect(workerNode.onBackPressure).toBeUndefined()
+    }
     pool.enableTasksQueue(true)
     expect(pool.opts.enableTasksQueue).toBe(true)
-    expect(pool.opts.tasksQueueOptions).toStrictEqual({ concurrency: 1 })
+    expect(pool.opts.tasksQueueOptions).toStrictEqual({
+      concurrency: 1,
+      size: 4,
+      taskStealing: true,
+      tasksStealingOnBackPressure: true
+    })
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.onEmptyQueue).toBeInstanceOf(Function)
+      expect(workerNode.onBackPressure).toBeInstanceOf(Function)
+    }
     pool.enableTasksQueue(true, { concurrency: 2 })
     expect(pool.opts.enableTasksQueue).toBe(true)
-    expect(pool.opts.tasksQueueOptions).toStrictEqual({ concurrency: 2 })
+    expect(pool.opts.tasksQueueOptions).toStrictEqual({
+      concurrency: 2,
+      size: 4,
+      taskStealing: true,
+      tasksStealingOnBackPressure: true
+    })
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.onEmptyQueue).toBeInstanceOf(Function)
+      expect(workerNode.onBackPressure).toBeInstanceOf(Function)
+    }
     pool.enableTasksQueue(false)
     expect(pool.opts.enableTasksQueue).toBe(false)
     expect(pool.opts.tasksQueueOptions).toBeUndefined()
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.onEmptyQueue).toBeUndefined()
+      expect(workerNode.onBackPressure).toBeUndefined()
+    }
     await pool.destroy()
   })
 
@@ -500,26 +674,76 @@ describe('Abstract pool test suite', () => {
       './tests/worker-files/thread/testWorker.js',
       { enableTasksQueue: true }
     )
-    expect(pool.opts.tasksQueueOptions).toStrictEqual({ concurrency: 1 })
-    pool.setTasksQueueOptions({ concurrency: 2 })
-    expect(pool.opts.tasksQueueOptions).toStrictEqual({ concurrency: 2 })
+    expect(pool.opts.tasksQueueOptions).toStrictEqual({
+      concurrency: 1,
+      size: 4,
+      taskStealing: true,
+      tasksStealingOnBackPressure: true
+    })
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.onEmptyQueue).toBeInstanceOf(Function)
+      expect(workerNode.onBackPressure).toBeInstanceOf(Function)
+    }
+    pool.setTasksQueueOptions({
+      concurrency: 2,
+      taskStealing: false,
+      tasksStealingOnBackPressure: false
+    })
+    expect(pool.opts.tasksQueueOptions).toStrictEqual({
+      concurrency: 2,
+      size: 4,
+      taskStealing: false,
+      tasksStealingOnBackPressure: false
+    })
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.onEmptyQueue).toBeUndefined()
+      expect(workerNode.onBackPressure).toBeUndefined()
+    }
+    pool.setTasksQueueOptions({
+      concurrency: 1,
+      taskStealing: true,
+      tasksStealingOnBackPressure: true
+    })
+    expect(pool.opts.tasksQueueOptions).toStrictEqual({
+      concurrency: 1,
+      size: 4,
+      taskStealing: true,
+      tasksStealingOnBackPressure: true
+    })
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.onEmptyQueue).toBeInstanceOf(Function)
+      expect(workerNode.onBackPressure).toBeInstanceOf(Function)
+    }
     expect(() =>
       pool.setTasksQueueOptions('invalidTasksQueueOptions')
     ).toThrowError(
       new TypeError('Invalid tasks queue options: must be a plain object')
     )
     expect(() => pool.setTasksQueueOptions({ concurrency: 0 })).toThrowError(
-      new Error(
-        'Invalid worker tasks concurrency: 0 is a negative integer or zero'
+      new RangeError(
+        'Invalid worker node tasks concurrency: 0 is a negative integer or zero'
       )
     )
     expect(() => pool.setTasksQueueOptions({ concurrency: -1 })).toThrowError(
-      new Error(
-        'Invalid worker tasks concurrency: -1 is a negative integer or zero'
+      new RangeError(
+        'Invalid worker node tasks concurrency: -1 is a negative integer or zero'
       )
     )
     expect(() => pool.setTasksQueueOptions({ concurrency: 0.2 })).toThrowError(
-      new TypeError('Invalid worker tasks concurrency: must be an integer')
+      new TypeError('Invalid worker node tasks concurrency: must be an integer')
+    )
+    expect(() => pool.setTasksQueueOptions({ size: 0 })).toThrowError(
+      new RangeError(
+        'Invalid worker node tasks queue size: 0 is a negative integer or zero'
+      )
+    )
+    expect(() => pool.setTasksQueueOptions({ size: -1 })).toThrowError(
+      new RangeError(
+        'Invalid worker node tasks queue size: -1 is a negative integer or zero'
+      )
+    )
+    expect(() => pool.setTasksQueueOptions({ size: 0.2 })).toThrowError(
+      new TypeError('Invalid worker node tasks queue size: must be an integer')
     )
     await pool.destroy()
   })
@@ -533,6 +757,7 @@ describe('Abstract pool test suite', () => {
       version,
       type: PoolTypes.fixed,
       worker: WorkerTypes.thread,
+      started: true,
       ready: true,
       strategy: WorkerChoiceStrategies.ROUND_ROBIN,
       minSize: numberOfWorkers,
@@ -554,6 +779,7 @@ describe('Abstract pool test suite', () => {
       version,
       type: PoolTypes.dynamic,
       worker: WorkerTypes.cluster,
+      started: true,
       ready: true,
       strategy: WorkerChoiceStrategies.ROUND_ROBIN,
       minSize: Math.floor(numberOfWorkers / 2),
@@ -574,26 +800,28 @@ describe('Abstract pool test suite', () => {
       './tests/worker-files/cluster/testWorker.js'
     )
     for (const workerNode of pool.workerNodes) {
+      expect(workerNode).toBeInstanceOf(WorkerNode)
       expect(workerNode.usage).toStrictEqual({
         tasks: {
           executed: 0,
           executing: 0,
           queued: 0,
           maxQueued: 0,
+          stolen: 0,
           failed: 0
         },
         runTime: {
-          history: expect.any(CircularArray)
+          history: new CircularArray()
         },
         waitTime: {
-          history: expect.any(CircularArray)
+          history: new CircularArray()
         },
         elu: {
           idle: {
-            history: expect.any(CircularArray)
+            history: new CircularArray()
           },
           active: {
-            history: expect.any(CircularArray)
+            history: new CircularArray()
           }
         }
       })
@@ -607,8 +835,8 @@ describe('Abstract pool test suite', () => {
       './tests/worker-files/cluster/testWorker.js'
     )
     for (const workerNode of pool.workerNodes) {
-      expect(workerNode.tasksQueue).toBeDefined()
-      expect(workerNode.tasksQueue).toBeInstanceOf(Queue)
+      expect(workerNode).toBeInstanceOf(WorkerNode)
+      expect(workerNode.tasksQueue).toBeInstanceOf(Deque)
       expect(workerNode.tasksQueue.size).toBe(0)
       expect(workerNode.tasksQueue.maxSize).toBe(0)
     }
@@ -619,11 +847,12 @@ describe('Abstract pool test suite', () => {
       './tests/worker-files/thread/testWorker.js'
     )
     for (const workerNode of pool.workerNodes) {
-      expect(workerNode.tasksQueue).toBeDefined()
-      expect(workerNode.tasksQueue).toBeInstanceOf(Queue)
+      expect(workerNode).toBeInstanceOf(WorkerNode)
+      expect(workerNode.tasksQueue).toBeInstanceOf(Deque)
       expect(workerNode.tasksQueue.size).toBe(0)
       expect(workerNode.tasksQueue.maxSize).toBe(0)
     }
+    await pool.destroy()
   })
 
   it('Verify that pool worker info are initialized', async () => {
@@ -632,6 +861,7 @@ describe('Abstract pool test suite', () => {
       './tests/worker-files/cluster/testWorker.js'
     )
     for (const workerNode of pool.workerNodes) {
+      expect(workerNode).toBeInstanceOf(WorkerNode)
       expect(workerNode.info).toStrictEqual({
         id: expect.any(Number),
         type: WorkerTypes.cluster,
@@ -646,6 +876,7 @@ describe('Abstract pool test suite', () => {
       './tests/worker-files/thread/testWorker.js'
     )
     for (const workerNode of pool.workerNodes) {
+      expect(workerNode).toBeInstanceOf(WorkerNode)
       expect(workerNode.info).toStrictEqual({
         id: expect.any(Number),
         type: WorkerTypes.thread,
@@ -653,6 +884,54 @@ describe('Abstract pool test suite', () => {
         ready: true
       })
     }
+    await pool.destroy()
+  })
+
+  it('Verify that pool can be started after initialization', async () => {
+    const pool = new FixedClusterPool(
+      numberOfWorkers,
+      './tests/worker-files/cluster/testWorker.js',
+      {
+        startWorkers: false
+      }
+    )
+    expect(pool.info.started).toBe(false)
+    expect(pool.info.ready).toBe(false)
+    expect(pool.workerNodes).toStrictEqual([])
+    await expect(pool.execute()).rejects.toThrowError(
+      new Error('Cannot execute a task on not started pool')
+    )
+    pool.start()
+    expect(pool.info.started).toBe(true)
+    expect(pool.info.ready).toBe(true)
+    expect(pool.workerNodes.length).toBe(numberOfWorkers)
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode).toBeInstanceOf(WorkerNode)
+    }
+    await pool.destroy()
+  })
+
+  it('Verify that pool execute() arguments are checked', async () => {
+    const pool = new FixedClusterPool(
+      numberOfWorkers,
+      './tests/worker-files/cluster/testWorker.js'
+    )
+    await expect(pool.execute(undefined, 0)).rejects.toThrowError(
+      new TypeError('name argument must be a string')
+    )
+    await expect(pool.execute(undefined, '')).rejects.toThrowError(
+      new TypeError('name argument must not be an empty string')
+    )
+    await expect(pool.execute(undefined, undefined, {})).rejects.toThrowError(
+      new TypeError('transferList argument must be an array')
+    )
+    await expect(pool.execute(undefined, 'unknown')).rejects.toBe(
+      "Task function 'unknown' not found"
+    )
+    await pool.destroy()
+    await expect(pool.execute()).rejects.toThrowError(
+      new Error('Cannot execute a task on not started pool')
+    )
   })
 
   it('Verify that pool worker tasks usage are computed', async () => {
@@ -672,6 +951,7 @@ describe('Abstract pool test suite', () => {
           executing: maxMultiplier,
           queued: 0,
           maxQueued: 0,
+          stolen: 0,
           failed: 0
         },
         runTime: {
@@ -698,6 +978,7 @@ describe('Abstract pool test suite', () => {
           executing: 0,
           queued: 0,
           maxQueued: 0,
+          stolen: 0,
           failed: 0
         },
         runTime: {
@@ -738,6 +1019,7 @@ describe('Abstract pool test suite', () => {
           executing: 0,
           queued: 0,
           maxQueued: 0,
+          stolen: 0,
           failed: 0
         },
         runTime: {
@@ -756,7 +1038,9 @@ describe('Abstract pool test suite', () => {
         }
       })
       expect(workerNode.usage.tasks.executed).toBeGreaterThan(0)
-      expect(workerNode.usage.tasks.executed).toBeLessThanOrEqual(maxMultiplier)
+      expect(workerNode.usage.tasks.executed).toBeLessThanOrEqual(
+        numberOfWorkers * maxMultiplier
+      )
       expect(workerNode.usage.runTime.history.length).toBe(0)
       expect(workerNode.usage.waitTime.history.length).toBe(0)
       expect(workerNode.usage.elu.idle.history.length).toBe(0)
@@ -770,6 +1054,7 @@ describe('Abstract pool test suite', () => {
           executing: 0,
           queued: 0,
           maxQueued: 0,
+          stolen: 0,
           failed: 0
         },
         runTime: {
@@ -803,7 +1088,7 @@ describe('Abstract pool test suite', () => {
     )
     let poolInfo
     let poolReady = 0
-    pool.emitter.on(PoolEvents.ready, (info) => {
+    pool.emitter.on(PoolEvents.ready, info => {
       ++poolReady
       poolInfo = info
     })
@@ -813,6 +1098,7 @@ describe('Abstract pool test suite', () => {
       version,
       type: PoolTypes.dynamic,
       worker: WorkerTypes.cluster,
+      started: true,
       ready: true,
       strategy: WorkerChoiceStrategies.ROUND_ROBIN,
       minSize: expect.any(Number),
@@ -835,7 +1121,7 @@ describe('Abstract pool test suite', () => {
     const promises = new Set()
     let poolBusy = 0
     let poolInfo
-    pool.emitter.on(PoolEvents.busy, (info) => {
+    pool.emitter.on(PoolEvents.busy, info => {
       ++poolBusy
       poolInfo = info
     })
@@ -850,7 +1136,8 @@ describe('Abstract pool test suite', () => {
       version,
       type: PoolTypes.fixed,
       worker: WorkerTypes.thread,
-      ready: expect.any(Boolean),
+      started: true,
+      ready: true,
       strategy: WorkerChoiceStrategies.ROUND_ROBIN,
       minSize: expect.any(Number),
       maxSize: expect.any(Number),
@@ -873,7 +1160,7 @@ describe('Abstract pool test suite', () => {
     const promises = new Set()
     let poolFull = 0
     let poolInfo
-    pool.emitter.on(PoolEvents.full, (info) => {
+    pool.emitter.on(PoolEvents.full, info => {
       ++poolFull
       poolInfo = info
     })
@@ -886,7 +1173,8 @@ describe('Abstract pool test suite', () => {
       version,
       type: PoolTypes.dynamic,
       worker: WorkerTypes.thread,
-      ready: expect.any(Boolean),
+      started: true,
+      ready: true,
       strategy: WorkerChoiceStrategies.ROUND_ROBIN,
       minSize: expect.any(Number),
       maxSize: expect.any(Number),
@@ -900,7 +1188,7 @@ describe('Abstract pool test suite', () => {
     await pool.destroy()
   })
 
-  it.skip("Verify that pool event emitter 'backPressure' event can register a callback", async () => {
+  it("Verify that pool event emitter 'backPressure' event can register a callback", async () => {
     const pool = new FixedThreadPool(
       numberOfWorkers,
       './tests/worker-files/thread/testWorker.js',
@@ -908,32 +1196,25 @@ describe('Abstract pool test suite', () => {
         enableTasksQueue: true
       }
     )
-    for (const workerNode of pool.workerNodes) {
-      workerNode.hasBackPressure = sinon
-        .stub()
-        .onFirstCall()
-        .returns(true)
-        .returns(false)
-    }
+    sinon.stub(pool, 'hasBackPressure').returns(true)
     const promises = new Set()
     let poolBackPressure = 0
     let poolInfo
-    pool.emitter.on(PoolEvents.backPressure, (info) => {
+    pool.emitter.on(PoolEvents.backPressure, info => {
       ++poolBackPressure
       poolInfo = info
     })
-    for (let i = 0; i < numberOfWorkers * 2; i++) {
+    for (let i = 0; i < numberOfWorkers + 1; i++) {
       promises.add(pool.execute())
     }
-    // console.log(pool.info.backPressure)
     await Promise.all(promises)
-    // console.log(pool.info.backPressure)
     expect(poolBackPressure).toBe(1)
     expect(poolInfo).toStrictEqual({
       version,
-      type: PoolTypes.dynamic,
+      type: PoolTypes.fixed,
       worker: WorkerTypes.thread,
-      ready: expect.any(Boolean),
+      started: true,
+      ready: true,
       strategy: WorkerChoiceStrategies.ROUND_ROBIN,
       minSize: expect.any(Number),
       maxSize: expect.any(Number),
@@ -942,8 +1223,13 @@ describe('Abstract pool test suite', () => {
       busyWorkerNodes: expect.any(Number),
       executedTasks: expect.any(Number),
       executingTasks: expect.any(Number),
+      maxQueuedTasks: expect.any(Number),
+      queuedTasks: expect.any(Number),
+      backPressure: true,
+      stolenTasks: expect.any(Number),
       failedTasks: expect.any(Number)
     })
+    expect(pool.hasBackPressure.called).toBe(true)
     await pool.destroy()
   })
 
@@ -955,7 +1241,7 @@ describe('Abstract pool test suite', () => {
     )
     await waitPoolEvents(dynamicThreadPool, PoolEvents.ready, 1)
     expect(dynamicThreadPool.listTaskFunctions()).toStrictEqual([
-      'default',
+      DEFAULT_TASK_NAME,
       'jsonIntegerSerialization',
       'factorial',
       'fibonacci'
@@ -966,11 +1252,13 @@ describe('Abstract pool test suite', () => {
     )
     await waitPoolEvents(fixedClusterPool, PoolEvents.ready, 1)
     expect(fixedClusterPool.listTaskFunctions()).toStrictEqual([
-      'default',
+      DEFAULT_TASK_NAME,
       'jsonIntegerSerialization',
       'factorial',
       'fibonacci'
     ])
+    await dynamicThreadPool.destroy()
+    await fixedClusterPool.destroy()
   })
 
   it('Verify that multiple task functions worker is working', async () => {
@@ -992,7 +1280,7 @@ describe('Abstract pool test suite', () => {
     expect(pool.info.executedTasks).toBe(4)
     for (const workerNode of pool.workerNodes) {
       expect(workerNode.info.taskFunctions).toStrictEqual([
-        'default',
+        DEFAULT_TASK_NAME,
         'jsonIntegerSerialization',
         'factorial',
         'fibonacci'
@@ -1002,9 +1290,10 @@ describe('Abstract pool test suite', () => {
         expect(workerNode.getTaskFunctionWorkerUsage(name)).toStrictEqual({
           tasks: {
             executed: expect.any(Number),
-            executing: expect.any(Number),
+            executing: 0,
             failed: 0,
-            queued: 0
+            queued: 0,
+            stolen: 0
           },
           runTime: {
             history: expect.any(CircularArray)
@@ -1022,9 +1311,31 @@ describe('Abstract pool test suite', () => {
           }
         })
         expect(
-          workerNode.getTaskFunctionWorkerUsage(name).tasks.executing
-        ).toBeGreaterThanOrEqual(0)
+          workerNode.getTaskFunctionWorkerUsage(name).tasks.executed
+        ).toBeGreaterThan(0)
       }
+      expect(
+        workerNode.getTaskFunctionWorkerUsage(DEFAULT_TASK_NAME)
+      ).toStrictEqual(
+        workerNode.getTaskFunctionWorkerUsage(workerNode.info.taskFunctions[1])
+      )
     }
+    await pool.destroy()
+  })
+
+  it('Verify sendKillMessageToWorker()', async () => {
+    const pool = new DynamicClusterPool(
+      Math.floor(numberOfWorkers / 2),
+      numberOfWorkers,
+      './tests/worker-files/cluster/testWorker.js'
+    )
+    const workerNodeKey = 0
+    await expect(
+      pool.sendKillMessageToWorker(
+        workerNodeKey,
+        pool.workerNodes[workerNodeKey].info.id
+      )
+    ).resolves.toBeUndefined()
+    await pool.destroy()
   })
 })