fix: fix fair share algorithm implementation

[poolifier.git] / tests / pools / selection-strategies / selection-strategies.test.js

diff --git a/tests/pools/selection-strategies/selection-strategies.test.js b/tests/pools/selection-strategies/selection-strategies.test.js
index b1599a99511a18ea180dc71521fc19d3c34ba17d..392aafcf3a58a79f6744a37268b01415243a2b97 100644 (file)
--- a/tests/pools/selection-strategies/selection-strategies.test.js
+++ b/tests/pools/selection-strategies/selection-strategies.test.js
@@ -4,7 +4,7 @@ const {
   DynamicThreadPool,
   FixedThreadPool,
   FixedClusterPool
-} = require('../../../lib/index')
+} = require('../../../lib')
 
 describe('Selection strategies test suite', () => {
   const min = 0
@@ -33,63 +33,115 @@ describe('Selection strategies test suite', () => {
     await pool.destroy()
   })
 
-  it('Verify ROUND_ROBIN strategy is taken at pool creation', async () => {
-    const pool = new FixedThreadPool(
-      max,
-      './tests/worker-files/thread/testWorker.js',
-      { workerChoiceStrategy: WorkerChoiceStrategies.ROUND_ROBIN }
-    )
-    expect(pool.opts.workerChoiceStrategy).toBe(
-      WorkerChoiceStrategies.ROUND_ROBIN
-    )
-    expect(
-      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.ROUND_ROBIN
-      ).nextWorkerId
-    ).toBe(0)
-    // We need to clean up the resources after our test
-    await pool.destroy()
+  it('Verify available strategies are taken at pool creation', async () => {
+    for (const workerChoiceStrategy of Object.values(WorkerChoiceStrategies)) {
+      const pool = new FixedThreadPool(
+        max,
+        './tests/worker-files/thread/testWorker.js',
+        { workerChoiceStrategy }
+      )
+      expect(pool.opts.workerChoiceStrategy).toBe(workerChoiceStrategy)
+      expect(pool.workerChoiceStrategyContext.workerChoiceStrategy).toBe(
+        workerChoiceStrategy
+      )
+      await pool.destroy()
+    }
   })
 
-  it('Verify ROUND_ROBIN strategy can be set after pool creation', async () => {
-    const pool = new DynamicThreadPool(
-      min,
+  it('Verify available strategies can be set after pool creation', async () => {
+    for (const workerChoiceStrategy of Object.values(WorkerChoiceStrategies)) {
+      const pool = new DynamicThreadPool(
+        min,
+        max,
+        './tests/worker-files/thread/testWorker.js'
+      )
+      pool.setWorkerChoiceStrategy(workerChoiceStrategy)
+      expect(pool.opts.workerChoiceStrategy).toBe(workerChoiceStrategy)
+      expect(pool.workerChoiceStrategyContext.workerChoiceStrategy).toBe(
+        workerChoiceStrategy
+      )
+      await pool.destroy()
+    }
+  })
+
+  it('Verify available strategies default internals at pool creation', async () => {
+    const pool = new FixedThreadPool(
       max,
       './tests/worker-files/thread/testWorker.js'
     )
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.ROUND_ROBIN)
-    expect(pool.opts.workerChoiceStrategy).toBe(
-      WorkerChoiceStrategies.ROUND_ROBIN
-    )
-    // We need to clean up the resources after our test
+    for (const workerChoiceStrategy of Object.values(WorkerChoiceStrategies)) {
+      if (workerChoiceStrategy === WorkerChoiceStrategies.ROUND_ROBIN) {
+        expect(
+          pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+            workerChoiceStrategy
+          ).nextWorkerNodeId
+        ).toBe(0)
+      } else if (workerChoiceStrategy === WorkerChoiceStrategies.FAIR_SHARE) {
+        expect(
+          pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+            workerChoiceStrategy
+          ).workersVirtualTaskTimestamp
+        ).toBeInstanceOf(Array)
+        expect(
+          pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+            workerChoiceStrategy
+          ).workersVirtualTaskTimestamp.length
+        ).toBe(0)
+      } else if (
+        workerChoiceStrategy === WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
+      ) {
+        expect(
+          pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+            workerChoiceStrategy
+          ).currentWorkerNodeId
+        ).toBe(0)
+        expect(
+          pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+            workerChoiceStrategy
+          ).defaultWorkerWeight
+        ).toBeGreaterThan(0)
+        expect(
+          pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+            workerChoiceStrategy
+          ).workerVirtualTaskRunTime
+        ).toBe(0)
+      }
+    }
     await pool.destroy()
   })
 
   it('Verify ROUND_ROBIN strategy default tasks usage statistics requirements', async () => {
+    const workerChoiceStrategy = WorkerChoiceStrategies.ROUND_ROBIN
     let pool = new FixedThreadPool(
       max,
-      './tests/worker-files/thread/testWorker.js'
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
     )
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.ROUND_ROBIN)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().runTime
     ).toBe(false)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().avgRunTime
     ).toBe(false)
+    expect(
+      pool.workerChoiceStrategyContext.getRequiredStatistics().medRunTime
+    ).toBe(false)
     await pool.destroy()
     pool = new DynamicThreadPool(
       min,
       max,
-      './tests/worker-files/thread/testWorker.js'
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
     )
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.ROUND_ROBIN)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().runTime
     ).toBe(false)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().avgRunTime
     ).toBe(false)
+    expect(
+      pool.workerChoiceStrategyContext.getRequiredStatistics().medRunTime
+    ).toBe(false)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
@@ -100,15 +152,11 @@ describe('Selection strategies test suite', () => {
       './tests/worker-files/thread/testWorker.js',
       { workerChoiceStrategy: WorkerChoiceStrategies.ROUND_ROBIN }
     )
-    expect(pool.opts.workerChoiceStrategy).toBe(
-      WorkerChoiceStrategies.ROUND_ROBIN
-    )
     // TODO: Create a better test to cover `RoundRobinWorkerChoiceStrategy#choose`
-    const promises = []
-    for (let i = 0; i < max * 2; i++) {
-      promises.push(pool.execute())
+    const maxMultiplier = 2
+    for (let i = 0; i < max * maxMultiplier; i++) {
+      await pool.execute()
     }
-    await Promise.all(promises)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
@@ -120,40 +168,43 @@ describe('Selection strategies test suite', () => {
       './tests/worker-files/thread/testWorker.js',
       { workerChoiceStrategy: WorkerChoiceStrategies.ROUND_ROBIN }
     )
-    expect(pool.opts.workerChoiceStrategy).toBe(
-      WorkerChoiceStrategies.ROUND_ROBIN
-    )
     // TODO: Create a better test to cover `RoundRobinWorkerChoiceStrategy#choose`
-    const promises = []
-    for (let i = 0; i < max * 2; i++) {
-      promises.push(pool.execute())
+    const maxMultiplier = 2
+    for (let i = 0; i < max * maxMultiplier; i++) {
+      await pool.execute()
     }
-    await Promise.all(promises)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
 
   it('Verify ROUND_ROBIN strategy runtime behavior', async () => {
+    const workerChoiceStrategy = WorkerChoiceStrategies.ROUND_ROBIN
     let pool = new FixedClusterPool(
       max,
-      './tests/worker-files/cluster/testWorker.js'
+      './tests/worker-files/cluster/testWorker.js',
+      { workerChoiceStrategy }
     )
     let results = new Set()
     for (let i = 0; i < max; i++) {
-      results.add(pool.chooseWorker()[1].id)
+      results.add(pool.chooseWorkerNode()[1].worker.id)
     }
     expect(results.size).toBe(max)
     await pool.destroy()
-    pool = new FixedThreadPool(max, './tests/worker-files/thread/testWorker.js')
+    pool = new FixedThreadPool(
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
     results = new Set()
     for (let i = 0; i < max; i++) {
-      results.add(pool.chooseWorker()[1].threadId)
+      results.add(pool.chooseWorkerNode()[1].worker.threadId)
     }
     expect(results.size).toBe(max)
     await pool.destroy()
   })
 
   it('Verify ROUND_ROBIN strategy internals are resets after setting it', async () => {
+    const workerChoiceStrategy = WorkerChoiceStrategies.ROUND_ROBIN
     let pool = new FixedThreadPool(
       max,
       './tests/worker-files/thread/testWorker.js',
@@ -161,14 +212,14 @@ describe('Selection strategies test suite', () => {
     )
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.ROUND_ROBIN
-      ).nextWorkerId
+        workerChoiceStrategy
+      ).nextWorkerNodeId
     ).toBeDefined()
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.ROUND_ROBIN)
+    pool.setWorkerChoiceStrategy(workerChoiceStrategy)
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.ROUND_ROBIN
-      ).nextWorkerId
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).nextWorkerNodeId
     ).toBe(0)
     await pool.destroy()
     pool = new DynamicThreadPool(
@@ -179,70 +230,51 @@ describe('Selection strategies test suite', () => {
     )
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.ROUND_ROBIN
-      ).nextWorkerId
+        workerChoiceStrategy
+      ).nextWorkerNodeId
     ).toBeDefined()
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.ROUND_ROBIN)
+    pool.setWorkerChoiceStrategy(workerChoiceStrategy)
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.ROUND_ROBIN
-      ).nextWorkerId
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).nextWorkerNodeId
     ).toBe(0)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
 
-  it('Verify LESS_USED strategy is taken at pool creation', async () => {
-    const pool = new FixedThreadPool(
-      max,
-      './tests/worker-files/thread/testWorker.js',
-      { workerChoiceStrategy: WorkerChoiceStrategies.LESS_USED }
-    )
-    expect(pool.opts.workerChoiceStrategy).toBe(
-      WorkerChoiceStrategies.LESS_USED
-    )
-    // We need to clean up the resources after our test
-    await pool.destroy()
-  })
-
-  it('Verify LESS_USED strategy can be set after pool creation', async () => {
-    const pool = new FixedThreadPool(
-      max,
-      './tests/worker-files/thread/testWorker.js'
-    )
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.LESS_USED)
-    expect(pool.opts.workerChoiceStrategy).toBe(
-      WorkerChoiceStrategies.LESS_USED
-    )
-    // We need to clean up the resources after our test
-    await pool.destroy()
-  })
-
   it('Verify LESS_USED strategy default tasks usage statistics requirements', async () => {
+    const workerChoiceStrategy = WorkerChoiceStrategies.LESS_USED
     let pool = new FixedThreadPool(
       max,
-      './tests/worker-files/thread/testWorker.js'
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
     )
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.LESS_USED)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().runTime
     ).toBe(false)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().avgRunTime
     ).toBe(false)
+    expect(
+      pool.workerChoiceStrategyContext.getRequiredStatistics().medRunTime
+    ).toBe(false)
     await pool.destroy()
     pool = new DynamicThreadPool(
       min,
       max,
-      './tests/worker-files/thread/testWorker.js'
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
     )
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.LESS_USED)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().runTime
     ).toBe(false)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().avgRunTime
     ).toBe(false)
+    expect(
+      pool.workerChoiceStrategyContext.getRequiredStatistics().medRunTime
+    ).toBe(false)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
@@ -254,11 +286,10 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.LESS_USED }
     )
     // TODO: Create a better test to cover `LessUsedWorkerChoiceStrategy#choose`
-    const promises = []
-    for (let i = 0; i < max * 2; i++) {
-      promises.push(pool.execute())
+    const maxMultiplier = 2
+    for (let i = 0; i < max * maxMultiplier; i++) {
+      await pool.execute()
     }
-    await Promise.all(promises)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
@@ -271,66 +302,46 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.LESS_USED }
     )
     // TODO: Create a better test to cover `LessUsedWorkerChoiceStrategy#choose`
-    const promises = []
-    for (let i = 0; i < max * 2; i++) {
-      promises.push(pool.execute())
+    const maxMultiplier = 2
+    for (let i = 0; i < max * maxMultiplier; i++) {
+      await pool.execute()
     }
-    await Promise.all(promises)
-    // We need to clean up the resources after our test
-    await pool.destroy()
-  })
-
-  it('Verify LESS_BUSY strategy is taken at pool creation', async () => {
-    const pool = new FixedThreadPool(
-      max,
-      './tests/worker-files/thread/testWorker.js',
-      { workerChoiceStrategy: WorkerChoiceStrategies.LESS_BUSY }
-    )
-    expect(pool.opts.workerChoiceStrategy).toBe(
-      WorkerChoiceStrategies.LESS_BUSY
-    )
-    // We need to clean up the resources after our test
-    await pool.destroy()
-  })
-
-  it('Verify LESS_BUSY strategy can be set after pool creation', async () => {
-    const pool = new FixedThreadPool(
-      max,
-      './tests/worker-files/thread/testWorker.js'
-    )
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.LESS_BUSY)
-    expect(pool.opts.workerChoiceStrategy).toBe(
-      WorkerChoiceStrategies.LESS_BUSY
-    )
     // We need to clean up the resources after our test
     await pool.destroy()
   })
 
   it('Verify LESS_BUSY strategy default tasks usage statistics requirements', async () => {
+    const workerChoiceStrategy = WorkerChoiceStrategies.LESS_BUSY
     let pool = new FixedThreadPool(
       max,
-      './tests/worker-files/thread/testWorker.js'
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
     )
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.LESS_BUSY)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().runTime
     ).toBe(true)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().avgRunTime
     ).toBe(false)
+    expect(
+      pool.workerChoiceStrategyContext.getRequiredStatistics().medRunTime
+    ).toBe(false)
     await pool.destroy()
     pool = new DynamicThreadPool(
       min,
       max,
-      './tests/worker-files/thread/testWorker.js'
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
     )
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.LESS_BUSY)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().runTime
     ).toBe(true)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().avgRunTime
     ).toBe(false)
+    expect(
+      pool.workerChoiceStrategyContext.getRequiredStatistics().medRunTime
+    ).toBe(false)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
@@ -342,11 +353,10 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.LESS_BUSY }
     )
     // TODO: Create a better test to cover `LessBusyWorkerChoiceStrategy#choose`
-    const promises = []
-    for (let i = 0; i < max * 2; i++) {
-      promises.push(pool.execute())
+    const maxMultiplier = 2
+    for (let i = 0; i < max * maxMultiplier; i++) {
+      await pool.execute()
     }
-    await Promise.all(promises)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
@@ -359,80 +369,46 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.LESS_BUSY }
     )
     // TODO: Create a better test to cover `LessBusyWorkerChoiceStrategy#choose`
-    const promises = []
-    for (let i = 0; i < max * 2; i++) {
-      promises.push(pool.execute())
-    }
-    await Promise.all(promises)
-    // We need to clean up the resources after our test
-    await pool.destroy()
-  })
-
-  it('Verify FAIR_SHARE strategy is taken at pool creation', async () => {
-    const pool = new FixedThreadPool(
-      max,
-      './tests/worker-files/thread/testWorker.js',
-      { workerChoiceStrategy: WorkerChoiceStrategies.FAIR_SHARE }
-    )
-    expect(pool.opts.workerChoiceStrategy).toBe(
-      WorkerChoiceStrategies.FAIR_SHARE
-    )
-    for (const workerKey of pool.workerChoiceStrategyContext.workerChoiceStrategies
-      .get(WorkerChoiceStrategies.FAIR_SHARE)
-      .workerLastVirtualTaskTimestamp.keys()) {
-      expect(
-        pool.workerChoiceStrategyContext.workerChoiceStrategies
-          .get(WorkerChoiceStrategies.FAIR_SHARE)
-          .workerLastVirtualTaskTimestamp.get(workerKey).start
-      ).toBe(0)
-      expect(
-        pool.workerChoiceStrategyContext.workerChoiceStrategies
-          .get(WorkerChoiceStrategies.FAIR_SHARE)
-          .workerLastVirtualTaskTimestamp.get(workerKey).end
-      ).toBe(0)
+    const maxMultiplier = 2
+    for (let i = 0; i < max * maxMultiplier; i++) {
+      await pool.execute()
     }
     // We need to clean up the resources after our test
     await pool.destroy()
   })
 
-  it('Verify FAIR_SHARE strategy can be set after pool creation', async () => {
-    const pool = new FixedThreadPool(
-      max,
-      './tests/worker-files/thread/testWorker.js'
-    )
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.FAIR_SHARE)
-    expect(pool.opts.workerChoiceStrategy).toBe(
-      WorkerChoiceStrategies.FAIR_SHARE
-    )
-    // We need to clean up the resources after our test
-    await pool.destroy()
-  })
-
   it('Verify FAIR_SHARE strategy default tasks usage statistics requirements', async () => {
+    const workerChoiceStrategy = WorkerChoiceStrategies.FAIR_SHARE
     let pool = new FixedThreadPool(
       max,
-      './tests/worker-files/thread/testWorker.js'
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
     )
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.FAIR_SHARE)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().runTime
     ).toBe(true)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().avgRunTime
     ).toBe(true)
+    expect(
+      pool.workerChoiceStrategyContext.getRequiredStatistics().medRunTime
+    ).toBe(false)
     await pool.destroy()
     pool = new DynamicThreadPool(
       min,
       max,
-      './tests/worker-files/thread/testWorker.js'
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
     )
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.FAIR_SHARE)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().runTime
     ).toBe(true)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().avgRunTime
     ).toBe(true)
+    expect(
+      pool.workerChoiceStrategyContext.getRequiredStatistics().medRunTime
+    ).toBe(false)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
@@ -444,16 +420,21 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.FAIR_SHARE }
     )
     // TODO: Create a better test to cover `FairShareChoiceStrategy#choose`
-    const promises = []
-    for (let i = 0; i < max * 2; i++) {
-      promises.push(pool.execute())
+    const maxMultiplier = 2
+    for (let i = 0; i < max * maxMultiplier; i++) {
+      await pool.execute()
+    }
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.tasksUsage.avgRunTime).toBeDefined()
+      expect(workerNode.tasksUsage.avgRunTime).toBeGreaterThanOrEqual(0)
+      expect(workerNode.tasksUsage.medRunTime).toBeDefined()
+      expect(workerNode.tasksUsage.medRunTime).toBe(0)
     }
-    await Promise.all(promises)
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.FAIR_SHARE
-      ).workerLastVirtualTaskTimestamp.size
-    ).toBe(pool.workers.length)
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).workersVirtualTaskTimestamp.length
+    ).toBe(pool.workerNodes.length)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
@@ -466,153 +447,163 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.FAIR_SHARE }
     )
     // TODO: Create a better test to cover `FairShareChoiceStrategy#choose`
-    const promises = []
     const maxMultiplier = 2
     for (let i = 0; i < max * maxMultiplier; i++) {
-      promises.push(pool.execute())
+      await pool.execute()
     }
-    await Promise.all(promises)
-    // if (process.platform !== 'win32') {
-    //   expect(
-    //     pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-    //       WorkerChoiceStrategies.FAIR_SHARE
-    //     ).workerLastVirtualTaskTimestamp.size
-    //   ).toBe(pool.workers.length)
-    // }
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.tasksUsage.avgRunTime).toBeDefined()
+      expect(workerNode.tasksUsage.avgRunTime).toBeGreaterThanOrEqual(0)
+      expect(workerNode.tasksUsage.medRunTime).toBeDefined()
+      expect(workerNode.tasksUsage.medRunTime).toBe(0)
+    }
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).workersVirtualTaskTimestamp.length
+    ).toBe(pool.workerNodes.length)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
 
-  it('Verify FAIR_SHARE strategy internals are resets after setting it', async () => {
-    let pool = new FixedThreadPool(
-      max,
-      './tests/worker-files/thread/testWorker.js'
-    )
-    expect(
-      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.FAIR_SHARE
-      ).workerLastVirtualTaskTimestamp
-    ).toBeDefined()
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.FAIR_SHARE)
-    for (const workerKey of pool.workerChoiceStrategyContext.workerChoiceStrategies
-      .get(WorkerChoiceStrategies.FAIR_SHARE)
-      .workerLastVirtualTaskTimestamp.keys()) {
-      expect(
-        pool.workerChoiceStrategyContext.workerChoiceStrategies
-          .get(WorkerChoiceStrategies.FAIR_SHARE)
-          .workerLastVirtualTaskTimestamp.get(workerKey).start
-      ).toBe(0)
-      expect(
-        pool.workerChoiceStrategyContext.workerChoiceStrategies
-          .get(WorkerChoiceStrategies.FAIR_SHARE)
-          .workerLastVirtualTaskTimestamp.get(workerKey).end
-      ).toBe(0)
-    }
-    await pool.destroy()
-    pool = new DynamicThreadPool(
+  it('Verify FAIR_SHARE strategy can be run in a dynamic pool with median run time statistic', async () => {
+    const pool = new DynamicThreadPool(
       min,
       max,
-      './tests/worker-files/thread/testWorker.js'
+      './tests/worker-files/thread/testWorker.js',
+      {
+        workerChoiceStrategy: WorkerChoiceStrategies.FAIR_SHARE,
+        workerChoiceStrategyOptions: {
+          medRunTime: true
+        }
+      }
     )
+    // TODO: Create a better test to cover `FairShareChoiceStrategy#choose`
+    const maxMultiplier = 2
+    for (let i = 0; i < max * maxMultiplier; i++) {
+      await pool.execute()
+    }
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.tasksUsage.avgRunTime).toBeDefined()
+      expect(workerNode.tasksUsage.avgRunTime).toBe(0)
+      expect(workerNode.tasksUsage.medRunTime).toBeDefined()
+      expect(workerNode.tasksUsage.medRunTime).toBeGreaterThanOrEqual(0)
+    }
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.FAIR_SHARE
-      ).workerLastVirtualTaskTimestamp
-    ).toBeDefined()
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.FAIR_SHARE)
-    for (const workerKey of pool.workerChoiceStrategyContext.workerChoiceStrategies
-      .get(WorkerChoiceStrategies.FAIR_SHARE)
-      .workerLastVirtualTaskTimestamp.keys()) {
-      expect(
-        pool.workerChoiceStrategyContext.workerChoiceStrategies
-          .get(WorkerChoiceStrategies.FAIR_SHARE)
-          .workerLastVirtualTaskTimestamp.get(workerKey).start
-      ).toBe(0)
-      expect(
-        pool.workerChoiceStrategyContext.workerChoiceStrategies
-          .get(WorkerChoiceStrategies.FAIR_SHARE)
-          .workerLastVirtualTaskTimestamp.get(workerKey).end
-      ).toBe(0)
-    }
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).workersVirtualTaskTimestamp.length
+    ).toBe(pool.workerNodes.length)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
 
-  it('Verify WEIGHTED_ROUND_ROBIN strategy is taken at pool creation', async () => {
-    const pool = new FixedThreadPool(
+  it('Verify FAIR_SHARE strategy internals are resets after setting it', async () => {
+    const workerChoiceStrategy = WorkerChoiceStrategies.FAIR_SHARE
+    let pool = new FixedThreadPool(
       max,
-      './tests/worker-files/thread/testWorker.js',
-      { workerChoiceStrategy: WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN }
-    )
-    expect(pool.opts.workerChoiceStrategy).toBe(
-      WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
+      './tests/worker-files/thread/testWorker.js'
     )
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
-      ).currentWorkerId
+        workerChoiceStrategy
+      ).workersVirtualTaskTimestamp
+    ).toBeInstanceOf(Array)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).workersVirtualTaskTimestamp.length
     ).toBe(0)
+    pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+      workerChoiceStrategy
+    ).workersVirtualTaskTimestamp[0] = 0
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
-      ).defaultWorkerWeight
-    ).toBeGreaterThan(0)
-    for (const workerKey of pool.workerChoiceStrategyContext.workerChoiceStrategies
-      .get(WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN)
-      .workersTaskRunTime.keys()) {
-      expect(
-        pool.workerChoiceStrategyContext.workerChoiceStrategies
-          .get(WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN)
-          .workersTaskRunTime.get(workerKey).weight
-      ).toBeGreaterThan(0)
-      expect(
-        pool.workerChoiceStrategyContext.workerChoiceStrategies
-          .get(WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN)
-          .workersTaskRunTime.get(workerKey).runTime
-      ).toBe(0)
-    }
-    // We need to clean up the resources after our test
+        workerChoiceStrategy
+      ).workersVirtualTaskTimestamp.length
+    ).toBe(1)
+    pool.setWorkerChoiceStrategy(workerChoiceStrategy)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).workersVirtualTaskTimestamp
+    ).toBeInstanceOf(Array)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).workersVirtualTaskTimestamp.length
+    ).toBe(0)
     await pool.destroy()
-  })
-
-  it('Verify WEIGHTED_ROUND_ROBIN strategy can be set after pool creation', async () => {
-    const pool = new FixedThreadPool(
+    pool = new DynamicThreadPool(
+      min,
       max,
       './tests/worker-files/thread/testWorker.js'
     )
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN)
-    expect(pool.opts.workerChoiceStrategy).toBe(
-      WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
-    )
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).workersVirtualTaskTimestamp
+    ).toBeInstanceOf(Array)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).workersVirtualTaskTimestamp.length
+    ).toBe(0)
+    pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+      workerChoiceStrategy
+    ).workersVirtualTaskTimestamp[0] = 0
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).workersVirtualTaskTimestamp.length
+    ).toBe(1)
+    pool.setWorkerChoiceStrategy(workerChoiceStrategy)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).workersVirtualTaskTimestamp
+    ).toBeInstanceOf(Array)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).workersVirtualTaskTimestamp.length
+    ).toBe(0)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
 
   it('Verify WEIGHTED_ROUND_ROBIN strategy default tasks usage statistics requirements', async () => {
+    const workerChoiceStrategy = WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
     let pool = new FixedThreadPool(
       max,
-      './tests/worker-files/thread/testWorker.js'
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
     )
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().runTime
     ).toBe(true)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().avgRunTime
     ).toBe(true)
+    expect(
+      pool.workerChoiceStrategyContext.getRequiredStatistics().medRunTime
+    ).toBe(false)
     await pool.destroy()
     pool = new DynamicThreadPool(
       min,
       max,
-      './tests/worker-files/thread/testWorker.js'
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
     )
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().runTime
     ).toBe(true)
     expect(
       pool.workerChoiceStrategyContext.getRequiredStatistics().avgRunTime
     ).toBe(true)
+    expect(
+      pool.workerChoiceStrategyContext.getRequiredStatistics().medRunTime
+    ).toBe(false)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
@@ -624,16 +615,26 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN }
     )
     // TODO: Create a better test to cover `WeightedRoundRobinWorkerChoiceStrategy#choose`
-    const promises = []
-    for (let i = 0; i < max * 2; i++) {
-      promises.push(pool.execute())
+    const maxMultiplier = 2
+    for (let i = 0; i < max * maxMultiplier; i++) {
+      await pool.execute()
     }
-    await Promise.all(promises)
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.tasksUsage.avgRunTime).toBeDefined()
+      expect(workerNode.tasksUsage.avgRunTime).toBeGreaterThanOrEqual(0)
+      expect(workerNode.tasksUsage.medRunTime).toBeDefined()
+      expect(workerNode.tasksUsage.medRunTime).toBe(0)
+    }
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).defaultWorkerWeight
+    ).toBeGreaterThan(0)
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
-      ).workersTaskRunTime.size
-    ).toBe(pool.workers.length)
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).workerVirtualTaskRunTime
+    ).toBeGreaterThanOrEqual(0)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
@@ -646,66 +647,104 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN }
     )
     // TODO: Create a better test to cover `WeightedRoundRobinWorkerChoiceStrategy#choose`
-    const promises = []
-    const maxMultiplier =
+    const maxMultiplier = 2
+    for (let i = 0; i < max * maxMultiplier; i++) {
+      await pool.execute()
+    }
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.tasksUsage.avgRunTime).toBeDefined()
+      expect(workerNode.tasksUsage.avgRunTime).toBeGreaterThanOrEqual(0)
+      expect(workerNode.tasksUsage.medRunTime).toBeDefined()
+      expect(workerNode.tasksUsage.medRunTime).toBe(0)
+    }
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).defaultWorkerWeight
+    ).toBeGreaterThan(0)
+    expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
-      ).defaultWorkerWeight * 50
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).workerVirtualTaskRunTime
+    ).toBeGreaterThanOrEqual(0)
+    // We need to clean up the resources after our test
+    await pool.destroy()
+  })
+
+  it('Verify WEIGHTED_ROUND_ROBIN strategy can be run in a dynamic pool with median run time statistic', async () => {
+    const pool = new DynamicThreadPool(
+      min,
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      {
+        workerChoiceStrategy: WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN,
+        workerChoiceStrategyOptions: {
+          medRunTime: true
+        }
+      }
+    )
+    // TODO: Create a better test to cover `WeightedRoundRobinWorkerChoiceStrategy#choose`
+    const maxMultiplier = 2
     for (let i = 0; i < max * maxMultiplier; i++) {
-      promises.push(pool.execute())
+      await pool.execute()
     }
-    await Promise.all(promises)
-    if (process.platform !== 'win32') {
-      expect(
-        pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-          WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
-        ).workersTaskRunTime.size
-      ).toBe(pool.workers.length)
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.tasksUsage.avgRunTime).toBeDefined()
+      expect(workerNode.tasksUsage.avgRunTime).toBe(0)
+      expect(workerNode.tasksUsage.medRunTime).toBeDefined()
+      expect(workerNode.tasksUsage.medRunTime).toBeGreaterThanOrEqual(0)
     }
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).defaultWorkerWeight
+    ).toBeGreaterThan(0)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).workerVirtualTaskRunTime
+    ).toBeGreaterThanOrEqual(0)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
 
   it('Verify WEIGHTED_ROUND_ROBIN strategy internals are resets after setting it', async () => {
+    const workerChoiceStrategy = WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
     let pool = new FixedThreadPool(
       max,
       './tests/worker-files/thread/testWorker.js'
     )
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
-      ).currentWorkerId
+        workerChoiceStrategy
+      ).currentWorkerNodeId
     ).toBeDefined()
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
+        workerChoiceStrategy
       ).defaultWorkerWeight
     ).toBeDefined()
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
-      ).workersTaskRunTime
+        workerChoiceStrategy
+      ).workerVirtualTaskRunTime
     ).toBeDefined()
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN)
+    pool.setWorkerChoiceStrategy(workerChoiceStrategy)
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
-      ).currentWorkerId
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).currentWorkerNodeId
     ).toBe(0)
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
       ).defaultWorkerWeight
     ).toBeGreaterThan(0)
-    for (const workerKey of pool.workerChoiceStrategyContext.workerChoiceStrategies
-      .get(WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN)
-      .workersTaskRunTime.keys()) {
-      expect(
-        pool.workerChoiceStrategyContext.workerChoiceStrategies
-          .get(WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN)
-          .workersTaskRunTime.get(workerKey).runTime
-      ).toBe(0)
-    }
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).workerVirtualTaskRunTime
+    ).toBe(0)
     await pool.destroy()
     pool = new DynamicThreadPool(
       min,
@@ -714,44 +753,40 @@ describe('Selection strategies test suite', () => {
     )
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
-      ).currentWorkerId
+        workerChoiceStrategy
+      ).currentWorkerNodeId
     ).toBeDefined()
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
+        workerChoiceStrategy
       ).defaultWorkerWeight
     ).toBeDefined()
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
-      ).workersTaskRunTime
+        workerChoiceStrategy
+      ).workerVirtualTaskRunTime
     ).toBeDefined()
-    pool.setWorkerChoiceStrategy(WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN)
+    pool.setWorkerChoiceStrategy(workerChoiceStrategy)
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
-      ).currentWorkerId
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).currentWorkerNodeId
     ).toBe(0)
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
-        WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
       ).defaultWorkerWeight
     ).toBeGreaterThan(0)
-    for (const workerKey of pool.workerChoiceStrategyContext.workerChoiceStrategies
-      .get(WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN)
-      .workersTaskRunTime.keys()) {
-      expect(
-        pool.workerChoiceStrategyContext.workerChoiceStrategies
-          .get(WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN)
-          .workersTaskRunTime.get(workerKey).runTime
-      ).toBe(0)
-    }
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).workerVirtualTaskRunTime
+    ).toBe(0)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
 
-  it('Verify unknown strategies throw error', () => {
+  it('Verify unknown strategy throw error', () => {
     expect(
       () =>
         new DynamicThreadPool(
@@ -760,8 +795,6 @@ describe('Selection strategies test suite', () => {
           './tests/worker-files/thread/testWorker.js',
           { workerChoiceStrategy: 'UNKNOWN_STRATEGY' }
         )
-    ).toThrowError(
-      new Error("Invalid worker choice strategy 'UNKNOWN_STRATEGY'")
-    )
+    ).toThrowError("Invalid worker choice strategy 'UNKNOWN_STRATEGY'")
   })
 })