test: improve coverage for fair share strategy

[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 94263ab49da7eb191206b399fc00876dd5115fd7..6b5dfdb567e5e220b63afafed22b91702dc699b9 100644 (file)
--- a/tests/pools/selection-strategies/selection-strategies.test.js
+++ b/tests/pools/selection-strategies/selection-strategies.test.js
@@ -1,9 +1,10 @@
 const { expect } = require('expect')
 const {
-  WorkerChoiceStrategies,
+  DynamicClusterPool,
   DynamicThreadPool,
+  FixedClusterPool,
   FixedThreadPool,
-  FixedClusterPool
+  WorkerChoiceStrategies
 } = require('../../../lib')
 const { CircularArray } = require('../../../lib/circular-array')
 
@@ -15,10 +16,14 @@ describe('Selection strategies test suite', () => {
     expect(WorkerChoiceStrategies.ROUND_ROBIN).toBe('ROUND_ROBIN')
     expect(WorkerChoiceStrategies.LEAST_USED).toBe('LEAST_USED')
     expect(WorkerChoiceStrategies.LEAST_BUSY).toBe('LEAST_BUSY')
+    expect(WorkerChoiceStrategies.LEAST_ELU).toBe('LEAST_ELU')
     expect(WorkerChoiceStrategies.FAIR_SHARE).toBe('FAIR_SHARE')
     expect(WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN).toBe(
       'WEIGHTED_ROUND_ROBIN'
     )
+    expect(WorkerChoiceStrategies.INTERLEAVED_WEIGHTED_ROUND_ROBIN).toBe(
+      'INTERLEAVED_WEIGHTED_ROUND_ROBIN'
+    )
   })
 
   it('Verify ROUND_ROBIN strategy is the default at pool creation', async () => {
@@ -61,6 +66,43 @@ describe('Selection strategies test suite', () => {
       expect(pool.workerChoiceStrategyContext.workerChoiceStrategy).toBe(
         workerChoiceStrategy
       )
+      expect(pool.opts.workerChoiceStrategyOptions).toStrictEqual({
+        retries: 6,
+        runTime: { median: false },
+        waitTime: { median: false },
+        elu: { median: false }
+      })
+      expect(pool.workerChoiceStrategyContext.opts).toStrictEqual({
+        retries: 6,
+        runTime: { median: false },
+        waitTime: { median: false },
+        elu: { median: false }
+      })
+      await pool.destroy()
+    }
+    for (const workerChoiceStrategy of Object.values(WorkerChoiceStrategies)) {
+      const pool = new DynamicClusterPool(
+        min,
+        max,
+        './tests/worker-files/cluster/testWorker.js'
+      )
+      pool.setWorkerChoiceStrategy(workerChoiceStrategy, { retries: 3 })
+      expect(pool.opts.workerChoiceStrategy).toBe(workerChoiceStrategy)
+      expect(pool.workerChoiceStrategyContext.workerChoiceStrategy).toBe(
+        workerChoiceStrategy
+      )
+      expect(pool.opts.workerChoiceStrategyOptions).toStrictEqual({
+        retries: 3,
+        runTime: { median: false },
+        waitTime: { median: false },
+        elu: { median: false }
+      })
+      expect(pool.workerChoiceStrategyContext.opts).toStrictEqual({
+        retries: 3,
+        runTime: { median: false },
+        waitTime: { median: false },
+        elu: { median: false }
+      })
       await pool.destroy()
     }
   })
@@ -75,7 +117,7 @@ describe('Selection strategies test suite', () => {
         expect(
           pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
             workerChoiceStrategy
-          ).nextWorkerNodeId
+          ).nextWorkerNodeKey
         ).toBe(0)
       } else if (workerChoiceStrategy === WorkerChoiceStrategies.FAIR_SHARE) {
         expect(
@@ -94,7 +136,7 @@ describe('Selection strategies test suite', () => {
         expect(
           pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
             workerChoiceStrategy
-          ).currentWorkerNodeId
+          ).nextWorkerNodeKey
         ).toBe(0)
         expect(
           pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
@@ -111,7 +153,33 @@ describe('Selection strategies test suite', () => {
     await pool.destroy()
   })
 
-  it('Verify ROUND_ROBIN strategy default tasks usage statistics requirements', async () => {
+  it('Verify ROUND_ROBIN strategy default policy', async () => {
+    const workerChoiceStrategy = WorkerChoiceStrategies.ROUND_ROBIN
+    let pool = new FixedThreadPool(
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
+    expect(pool.workerChoiceStrategyContext.getStrategyPolicy()).toStrictEqual({
+      dynamicWorkerUsage: false,
+      dynamicWorkerReady: true
+    })
+    await pool.destroy()
+    pool = new DynamicThreadPool(
+      min,
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
+    expect(pool.workerChoiceStrategyContext.getStrategyPolicy()).toStrictEqual({
+      dynamicWorkerUsage: false,
+      dynamicWorkerReady: true
+    })
+    // We need to clean up the resources after our test
+    await pool.destroy()
+  })
+
+  it('Verify ROUND_ROBIN strategy default tasks statistics requirements', async () => {
     const workerChoiceStrategy = WorkerChoiceStrategies.ROUND_ROBIN
     let pool = new FixedThreadPool(
       max,
@@ -119,14 +187,23 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy }
     )
     expect(
-      pool.workerChoiceStrategyContext.getRequiredStatistics()
+      pool.workerChoiceStrategyContext.getTaskStatisticsRequirements()
     ).toStrictEqual({
-      runTime: false,
-      avgRunTime: false,
-      medRunTime: false,
-      waitTime: false,
-      avgWaitTime: false,
-      medWaitTime: false
+      runTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      waitTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      elu: {
+        aggregate: false,
+        average: false,
+        median: false
+      }
     })
     await pool.destroy()
     pool = new DynamicThreadPool(
@@ -136,14 +213,23 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy }
     )
     expect(
-      pool.workerChoiceStrategyContext.getRequiredStatistics()
+      pool.workerChoiceStrategyContext.getTaskStatisticsRequirements()
     ).toStrictEqual({
-      runTime: false,
-      avgRunTime: false,
-      medRunTime: false,
-      waitTime: false,
-      avgWaitTime: false,
-      medWaitTime: false
+      runTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      waitTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      elu: {
+        aggregate: false,
+        average: false,
+        median: false
+      }
     })
     // We need to clean up the resources after our test
     await pool.destroy()
@@ -156,10 +242,43 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.ROUND_ROBIN }
     )
     // TODO: Create a better test to cover `RoundRobinWorkerChoiceStrategy#choose`
+    const promises = new Set()
     const maxMultiplier = 2
     for (let i = 0; i < max * maxMultiplier; i++) {
-      await pool.execute()
+      promises.add(pool.execute())
     }
+    await Promise.all(promises)
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.usage).toStrictEqual({
+        tasks: {
+          executed: maxMultiplier,
+          executing: 0,
+          queued: 0,
+          maxQueued: 0,
+          stolen: 0,
+          failed: 0
+        },
+        runTime: {
+          history: expect.any(CircularArray)
+        },
+        waitTime: {
+          history: expect.any(CircularArray)
+        },
+        elu: {
+          idle: {
+            history: expect.any(CircularArray)
+          },
+          active: {
+            history: expect.any(CircularArray)
+          }
+        }
+      })
+    }
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        WorkerChoiceStrategies.ROUND_ROBIN
+      ).nextWorkerNodeKey
+    ).toBe(0)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
@@ -172,10 +291,47 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.ROUND_ROBIN }
     )
     // TODO: Create a better test to cover `RoundRobinWorkerChoiceStrategy#choose`
+    const promises = new Set()
     const maxMultiplier = 2
     for (let i = 0; i < max * maxMultiplier; i++) {
-      await pool.execute()
+      promises.add(pool.execute())
+    }
+    await Promise.all(promises)
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.usage).toStrictEqual({
+        tasks: {
+          executed: expect.any(Number),
+          executing: 0,
+          queued: 0,
+          maxQueued: 0,
+          stolen: 0,
+          failed: 0
+        },
+        runTime: {
+          history: expect.any(CircularArray)
+        },
+        waitTime: {
+          history: expect.any(CircularArray)
+        },
+        elu: {
+          idle: {
+            history: expect.any(CircularArray)
+          },
+          active: {
+            history: expect.any(CircularArray)
+          }
+        }
+      })
+      expect(workerNode.usage.tasks.executed).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeLessThanOrEqual(
+        max * maxMultiplier
+      )
     }
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        WorkerChoiceStrategies.ROUND_ROBIN
+      ).nextWorkerNodeKey
+    ).toBe(0)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
@@ -216,13 +372,13 @@ describe('Selection strategies test suite', () => {
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
         workerChoiceStrategy
-      ).nextWorkerNodeId
+      ).nextWorkerNodeKey
     ).toBeDefined()
     pool.setWorkerChoiceStrategy(workerChoiceStrategy)
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
         pool.workerChoiceStrategyContext.workerChoiceStrategy
-      ).nextWorkerNodeId
+      ).nextWorkerNodeKey
     ).toBe(0)
     await pool.destroy()
     pool = new DynamicThreadPool(
@@ -234,19 +390,45 @@ describe('Selection strategies test suite', () => {
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
         workerChoiceStrategy
-      ).nextWorkerNodeId
+      ).nextWorkerNodeKey
     ).toBeDefined()
     pool.setWorkerChoiceStrategy(workerChoiceStrategy)
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
         pool.workerChoiceStrategyContext.workerChoiceStrategy
-      ).nextWorkerNodeId
+      ).nextWorkerNodeKey
     ).toBe(0)
     // We need to clean up the resources after our test
     await pool.destroy()
   })
 
-  it('Verify LEAST_USED strategy default tasks usage statistics requirements', async () => {
+  it('Verify LEAST_USED strategy default policy', async () => {
+    const workerChoiceStrategy = WorkerChoiceStrategies.LEAST_USED
+    let pool = new FixedThreadPool(
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
+    expect(pool.workerChoiceStrategyContext.getStrategyPolicy()).toStrictEqual({
+      dynamicWorkerUsage: false,
+      dynamicWorkerReady: true
+    })
+    await pool.destroy()
+    pool = new DynamicThreadPool(
+      min,
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
+    expect(pool.workerChoiceStrategyContext.getStrategyPolicy()).toStrictEqual({
+      dynamicWorkerUsage: false,
+      dynamicWorkerReady: true
+    })
+    // We need to clean up the resources after our test
+    await pool.destroy()
+  })
+
+  it('Verify LEAST_USED strategy default tasks statistics requirements', async () => {
     const workerChoiceStrategy = WorkerChoiceStrategies.LEAST_USED
     let pool = new FixedThreadPool(
       max,
@@ -254,14 +436,23 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy }
     )
     expect(
-      pool.workerChoiceStrategyContext.getRequiredStatistics()
+      pool.workerChoiceStrategyContext.getTaskStatisticsRequirements()
     ).toStrictEqual({
-      runTime: false,
-      avgRunTime: false,
-      medRunTime: false,
-      waitTime: false,
-      avgWaitTime: false,
-      medWaitTime: false
+      runTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      waitTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      elu: {
+        aggregate: false,
+        average: false,
+        median: false
+      }
     })
     await pool.destroy()
     pool = new DynamicThreadPool(
@@ -271,14 +462,23 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy }
     )
     expect(
-      pool.workerChoiceStrategyContext.getRequiredStatistics()
+      pool.workerChoiceStrategyContext.getTaskStatisticsRequirements()
     ).toStrictEqual({
-      runTime: false,
-      avgRunTime: false,
-      medRunTime: false,
-      waitTime: false,
-      avgWaitTime: false,
-      medWaitTime: false
+      runTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      waitTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      elu: {
+        aggregate: false,
+        average: false,
+        median: false
+      }
     })
     // We need to clean up the resources after our test
     await pool.destroy()
@@ -291,9 +491,41 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.LEAST_USED }
     )
     // TODO: Create a better test to cover `LeastUsedWorkerChoiceStrategy#choose`
+    const promises = new Set()
     const maxMultiplier = 2
     for (let i = 0; i < max * maxMultiplier; i++) {
-      await pool.execute()
+      promises.add(pool.execute())
+    }
+    await Promise.all(promises)
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.usage).toStrictEqual({
+        tasks: {
+          executed: expect.any(Number),
+          executing: 0,
+          queued: 0,
+          maxQueued: 0,
+          stolen: 0,
+          failed: 0
+        },
+        runTime: {
+          history: expect.any(CircularArray)
+        },
+        waitTime: {
+          history: expect.any(CircularArray)
+        },
+        elu: {
+          idle: {
+            history: expect.any(CircularArray)
+          },
+          active: {
+            history: expect.any(CircularArray)
+          }
+        }
+      })
+      expect(workerNode.usage.tasks.executed).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeLessThanOrEqual(
+        max * maxMultiplier
+      )
     }
     // We need to clean up the resources after our test
     await pool.destroy()
@@ -307,15 +539,73 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.LEAST_USED }
     )
     // TODO: Create a better test to cover `LeastUsedWorkerChoiceStrategy#choose`
+    const promises = new Set()
     const maxMultiplier = 2
     for (let i = 0; i < max * maxMultiplier; i++) {
-      await pool.execute()
+      promises.add(pool.execute())
+    }
+    await Promise.all(promises)
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.usage).toStrictEqual({
+        tasks: {
+          executed: expect.any(Number),
+          executing: 0,
+          queued: 0,
+          maxQueued: 0,
+          stolen: 0,
+          failed: 0
+        },
+        runTime: {
+          history: expect.any(CircularArray)
+        },
+        waitTime: {
+          history: expect.any(CircularArray)
+        },
+        elu: {
+          idle: {
+            history: expect.any(CircularArray)
+          },
+          active: {
+            history: expect.any(CircularArray)
+          }
+        }
+      })
+      expect(workerNode.usage.tasks.executed).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeLessThanOrEqual(
+        max * maxMultiplier
+      )
     }
     // We need to clean up the resources after our test
     await pool.destroy()
   })
 
-  it('Verify LEAST_BUSY strategy default tasks usage statistics requirements', async () => {
+  it('Verify LEAST_BUSY strategy default policy', async () => {
+    const workerChoiceStrategy = WorkerChoiceStrategies.LEAST_BUSY
+    let pool = new FixedThreadPool(
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
+    expect(pool.workerChoiceStrategyContext.getStrategyPolicy()).toStrictEqual({
+      dynamicWorkerUsage: false,
+      dynamicWorkerReady: true
+    })
+    await pool.destroy()
+    pool = new DynamicThreadPool(
+      min,
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
+    expect(pool.workerChoiceStrategyContext.getStrategyPolicy()).toStrictEqual({
+      dynamicWorkerUsage: false,
+      dynamicWorkerReady: true
+    })
+    // We need to clean up the resources after our test
+    await pool.destroy()
+  })
+
+  it('Verify LEAST_BUSY strategy default tasks statistics requirements', async () => {
     const workerChoiceStrategy = WorkerChoiceStrategies.LEAST_BUSY
     let pool = new FixedThreadPool(
       max,
@@ -323,14 +613,23 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy }
     )
     expect(
-      pool.workerChoiceStrategyContext.getRequiredStatistics()
+      pool.workerChoiceStrategyContext.getTaskStatisticsRequirements()
     ).toStrictEqual({
-      runTime: true,
-      avgRunTime: false,
-      medRunTime: false,
-      waitTime: false,
-      avgWaitTime: false,
-      medWaitTime: false
+      runTime: {
+        aggregate: true,
+        average: false,
+        median: false
+      },
+      waitTime: {
+        aggregate: true,
+        average: false,
+        median: false
+      },
+      elu: {
+        aggregate: false,
+        average: false,
+        median: false
+      }
     })
     await pool.destroy()
     pool = new DynamicThreadPool(
@@ -340,14 +639,23 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy }
     )
     expect(
-      pool.workerChoiceStrategyContext.getRequiredStatistics()
+      pool.workerChoiceStrategyContext.getTaskStatisticsRequirements()
     ).toStrictEqual({
-      runTime: true,
-      avgRunTime: false,
-      medRunTime: false,
-      waitTime: false,
-      avgWaitTime: false,
-      medWaitTime: false
+      runTime: {
+        aggregate: true,
+        average: false,
+        median: false
+      },
+      waitTime: {
+        aggregate: true,
+        average: false,
+        median: false
+      },
+      elu: {
+        aggregate: false,
+        average: false,
+        median: false
+      }
     })
     // We need to clean up the resources after our test
     await pool.destroy()
@@ -360,9 +668,51 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.LEAST_BUSY }
     )
     // TODO: Create a better test to cover `LeastBusyWorkerChoiceStrategy#choose`
+    const promises = new Set()
     const maxMultiplier = 2
     for (let i = 0; i < max * maxMultiplier; i++) {
-      await pool.execute()
+      promises.add(pool.execute())
+    }
+    await Promise.all(promises)
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.usage).toMatchObject({
+        tasks: {
+          executed: expect.any(Number),
+          executing: 0,
+          queued: 0,
+          maxQueued: 0,
+          stolen: 0,
+          failed: 0
+        },
+        runTime: {
+          history: expect.any(CircularArray)
+        },
+        waitTime: {
+          history: expect.any(CircularArray)
+        },
+        elu: {
+          idle: {
+            history: expect.any(CircularArray)
+          },
+          active: {
+            history: expect.any(CircularArray)
+          }
+        }
+      })
+      expect(workerNode.usage.tasks.executed).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeLessThanOrEqual(
+        max * maxMultiplier
+      )
+      if (workerNode.usage.runTime.aggregate == null) {
+        expect(workerNode.usage.runTime.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.runTime.aggregate).toBeGreaterThan(0)
+      }
+      if (workerNode.usage.waitTime.aggregate == null) {
+        expect(workerNode.usage.waitTime.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.waitTime.aggregate).toBeGreaterThan(0)
+      }
     }
     // We need to clean up the resources after our test
     await pool.destroy()
@@ -376,15 +726,292 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.LEAST_BUSY }
     )
     // TODO: Create a better test to cover `LeastBusyWorkerChoiceStrategy#choose`
+    const promises = new Set()
     const maxMultiplier = 2
     for (let i = 0; i < max * maxMultiplier; i++) {
-      await pool.execute()
+      promises.add(pool.execute())
+    }
+    await Promise.all(promises)
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.usage).toMatchObject({
+        tasks: {
+          executed: expect.any(Number),
+          executing: 0,
+          queued: 0,
+          maxQueued: 0,
+          stolen: 0,
+          failed: 0
+        },
+        runTime: {
+          history: expect.any(CircularArray)
+        },
+        waitTime: {
+          history: expect.any(CircularArray)
+        },
+        elu: {
+          idle: {
+            history: expect.any(CircularArray)
+          },
+          active: {
+            history: expect.any(CircularArray)
+          }
+        }
+      })
+      expect(workerNode.usage.tasks.executed).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeLessThanOrEqual(
+        max * maxMultiplier
+      )
+      if (workerNode.usage.runTime.aggregate == null) {
+        expect(workerNode.usage.runTime.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.runTime.aggregate).toBeGreaterThan(0)
+      }
+      if (workerNode.usage.waitTime.aggregate == null) {
+        expect(workerNode.usage.waitTime.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.waitTime.aggregate).toBeGreaterThan(0)
+      }
     }
     // We need to clean up the resources after our test
     await pool.destroy()
   })
 
-  it('Verify FAIR_SHARE strategy default tasks usage statistics requirements', async () => {
+  it('Verify LEAST_ELU strategy default policy', async () => {
+    const workerChoiceStrategy = WorkerChoiceStrategies.LEAST_ELU
+    let pool = new FixedThreadPool(
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
+    expect(pool.workerChoiceStrategyContext.getStrategyPolicy()).toStrictEqual({
+      dynamicWorkerUsage: false,
+      dynamicWorkerReady: true
+    })
+    await pool.destroy()
+    pool = new DynamicThreadPool(
+      min,
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
+    expect(pool.workerChoiceStrategyContext.getStrategyPolicy()).toStrictEqual({
+      dynamicWorkerUsage: false,
+      dynamicWorkerReady: true
+    })
+    // We need to clean up the resources after our test
+    await pool.destroy()
+  })
+
+  it('Verify LEAST_ELU strategy default tasks statistics requirements', async () => {
+    const workerChoiceStrategy = WorkerChoiceStrategies.LEAST_ELU
+    let pool = new FixedThreadPool(
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
+    expect(
+      pool.workerChoiceStrategyContext.getTaskStatisticsRequirements()
+    ).toStrictEqual({
+      runTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      waitTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      elu: {
+        aggregate: true,
+        average: false,
+        median: false
+      }
+    })
+    await pool.destroy()
+    pool = new DynamicThreadPool(
+      min,
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
+    expect(
+      pool.workerChoiceStrategyContext.getTaskStatisticsRequirements()
+    ).toStrictEqual({
+      runTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      waitTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      elu: {
+        aggregate: true,
+        average: false,
+        median: false
+      }
+    })
+    // We need to clean up the resources after our test
+    await pool.destroy()
+  })
+
+  it('Verify LEAST_ELU strategy can be run in a fixed pool', async () => {
+    const pool = new FixedThreadPool(
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy: WorkerChoiceStrategies.LEAST_ELU }
+    )
+    // TODO: Create a better test to cover `LeastEluWorkerChoiceStrategy#choose`
+    const promises = new Set()
+    const maxMultiplier = 2
+    for (let i = 0; i < max * maxMultiplier; i++) {
+      promises.add(pool.execute())
+    }
+    await Promise.all(promises)
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.usage).toMatchObject({
+        tasks: {
+          executed: expect.any(Number),
+          executing: 0,
+          queued: 0,
+          maxQueued: 0,
+          stolen: 0,
+          failed: 0
+        },
+        runTime: {
+          history: expect.any(CircularArray)
+        },
+        waitTime: {
+          history: expect.any(CircularArray)
+        },
+        elu: {
+          idle: {
+            history: expect.any(CircularArray)
+          },
+          active: {
+            history: expect.any(CircularArray)
+          }
+        }
+      })
+      expect(workerNode.usage.tasks.executed).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeLessThanOrEqual(
+        max * maxMultiplier
+      )
+      if (workerNode.usage.elu.active.aggregate == null) {
+        expect(workerNode.usage.elu.active.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.elu.active.aggregate).toBeGreaterThan(0)
+      }
+      if (workerNode.usage.elu.idle.aggregate == null) {
+        expect(workerNode.usage.elu.idle.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.elu.idle.aggregate).toBeGreaterThanOrEqual(0)
+      }
+      if (workerNode.usage.elu.utilization == null) {
+        expect(workerNode.usage.elu.utilization).toBeUndefined()
+      } else {
+        expect(workerNode.usage.elu.utilization).toBeGreaterThanOrEqual(0)
+        expect(workerNode.usage.elu.utilization).toBeLessThanOrEqual(1)
+      }
+    }
+    // We need to clean up the resources after our test
+    await pool.destroy()
+  })
+
+  it('Verify LEAST_ELU strategy can be run in a dynamic pool', async () => {
+    const pool = new DynamicThreadPool(
+      min,
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy: WorkerChoiceStrategies.LEAST_ELU }
+    )
+    // TODO: Create a better test to cover `LeastEluWorkerChoiceStrategy#choose`
+    const promises = new Set()
+    const maxMultiplier = 2
+    for (let i = 0; i < max * maxMultiplier; i++) {
+      promises.add(pool.execute())
+    }
+    await Promise.all(promises)
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.usage).toMatchObject({
+        tasks: {
+          executed: expect.any(Number),
+          executing: 0,
+          queued: 0,
+          maxQueued: 0,
+          stolen: 0,
+          failed: 0
+        },
+        runTime: {
+          history: expect.any(CircularArray)
+        },
+        waitTime: {
+          history: expect.any(CircularArray)
+        },
+        elu: {
+          idle: {
+            history: expect.any(CircularArray)
+          },
+          active: {
+            history: expect.any(CircularArray)
+          }
+        }
+      })
+      expect(workerNode.usage.tasks.executed).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeLessThanOrEqual(
+        max * maxMultiplier
+      )
+      if (workerNode.usage.elu.active.aggregate == null) {
+        expect(workerNode.usage.elu.active.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.elu.active.aggregate).toBeGreaterThan(0)
+      }
+      if (workerNode.usage.elu.idle.aggregate == null) {
+        expect(workerNode.usage.elu.idle.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.elu.idle.aggregate).toBeGreaterThanOrEqual(0)
+      }
+      if (workerNode.usage.elu.utilization == null) {
+        expect(workerNode.usage.elu.utilization).toBeUndefined()
+      } else {
+        expect(workerNode.usage.elu.utilization).toBeGreaterThanOrEqual(0)
+        expect(workerNode.usage.elu.utilization).toBeLessThanOrEqual(1)
+      }
+    }
+    // We need to clean up the resources after our test
+    await pool.destroy()
+  })
+
+  it('Verify FAIR_SHARE strategy default policy', async () => {
+    const workerChoiceStrategy = WorkerChoiceStrategies.FAIR_SHARE
+    let pool = new FixedThreadPool(
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
+    expect(pool.workerChoiceStrategyContext.getStrategyPolicy()).toStrictEqual({
+      dynamicWorkerUsage: false,
+      dynamicWorkerReady: true
+    })
+    await pool.destroy()
+    pool = new DynamicThreadPool(
+      min,
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
+    expect(pool.workerChoiceStrategyContext.getStrategyPolicy()).toStrictEqual({
+      dynamicWorkerUsage: false,
+      dynamicWorkerReady: true
+    })
+    // We need to clean up the resources after our test
+    await pool.destroy()
+  })
+
+  it('Verify FAIR_SHARE strategy default tasks statistics requirements', async () => {
     const workerChoiceStrategy = WorkerChoiceStrategies.FAIR_SHARE
     let pool = new FixedThreadPool(
       max,
@@ -392,14 +1019,23 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy }
     )
     expect(
-      pool.workerChoiceStrategyContext.getRequiredStatistics()
+      pool.workerChoiceStrategyContext.getTaskStatisticsRequirements()
     ).toStrictEqual({
-      runTime: true,
-      avgRunTime: true,
-      medRunTime: false,
-      waitTime: false,
-      avgWaitTime: false,
-      medWaitTime: false
+      runTime: {
+        aggregate: true,
+        average: true,
+        median: false
+      },
+      waitTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      elu: {
+        aggregate: true,
+        average: true,
+        median: false
+      }
     })
     await pool.destroy()
     pool = new DynamicThreadPool(
@@ -409,14 +1045,23 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy }
     )
     expect(
-      pool.workerChoiceStrategyContext.getRequiredStatistics()
+      pool.workerChoiceStrategyContext.getTaskStatisticsRequirements()
     ).toStrictEqual({
-      runTime: true,
-      avgRunTime: true,
-      medRunTime: false,
-      waitTime: false,
-      avgWaitTime: false,
-      medWaitTime: false
+      runTime: {
+        aggregate: true,
+        average: true,
+        median: false
+      },
+      waitTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      elu: {
+        aggregate: true,
+        average: true,
+        median: false
+      }
     })
     // We need to clean up the resources after our test
     await pool.destroy()
@@ -429,25 +1074,67 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.FAIR_SHARE }
     )
     // TODO: Create a better test to cover `FairShareChoiceStrategy#choose`
+    const promises = new Set()
     const maxMultiplier = 2
     for (let i = 0; i < max * maxMultiplier; i++) {
-      await pool.execute()
+      promises.add(pool.execute())
     }
+    await Promise.all(promises)
     for (const workerNode of pool.workerNodes) {
-      expect(workerNode.tasksUsage).toStrictEqual({
-        run: maxMultiplier,
-        running: 0,
-        runTime: expect.any(Number),
-        runTimeHistory: expect.any(CircularArray),
-        avgRunTime: expect.any(Number),
-        medRunTime: 0,
-        waitTime: 0,
-        waitTimeHistory: expect.any(CircularArray),
-        avgWaitTime: 0,
-        medWaitTime: 0,
-        error: 0
+      expect(workerNode.usage).toMatchObject({
+        tasks: {
+          executed: expect.any(Number),
+          executing: 0,
+          queued: 0,
+          maxQueued: 0,
+          stolen: 0,
+          failed: 0
+        },
+        runTime: {
+          history: expect.any(CircularArray)
+        },
+        waitTime: {
+          history: expect.any(CircularArray)
+        },
+        elu: {
+          idle: {
+            history: expect.any(CircularArray)
+          },
+          active: {
+            history: expect.any(CircularArray)
+          }
+        }
       })
-      expect(workerNode.tasksUsage.avgRunTime).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeLessThanOrEqual(
+        max * maxMultiplier
+      )
+      if (workerNode.usage.runTime.aggregate == null) {
+        expect(workerNode.usage.runTime.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.runTime.aggregate).toBeGreaterThan(0)
+      }
+      if (workerNode.usage.runTime.average == null) {
+        expect(workerNode.usage.runTime.average).toBeUndefined()
+      } else {
+        expect(workerNode.usage.runTime.average).toBeGreaterThan(0)
+      }
+      if (workerNode.usage.elu.active.aggregate == null) {
+        expect(workerNode.usage.elu.active.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.elu.active.aggregate).toBeGreaterThan(0)
+      }
+      if (workerNode.usage.elu.idle.aggregate == null) {
+        expect(workerNode.usage.elu.idle.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.elu.idle.aggregate).toBeGreaterThanOrEqual(0)
+      }
+      if (workerNode.usage.elu.utilization == null) {
+        expect(workerNode.usage.elu.utilization).toBeUndefined()
+      } else {
+        expect(workerNode.usage.elu.utilization).toBeGreaterThanOrEqual(0)
+        expect(workerNode.usage.elu.utilization).toBeLessThanOrEqual(1)
+      }
     }
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
@@ -466,25 +1153,67 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.FAIR_SHARE }
     )
     // TODO: Create a better test to cover `FairShareChoiceStrategy#choose`
+    const promises = new Set()
     const maxMultiplier = 2
     for (let i = 0; i < max * maxMultiplier; i++) {
-      await pool.execute()
+      promises.add(pool.execute())
     }
+    await Promise.all(promises)
     for (const workerNode of pool.workerNodes) {
-      expect(workerNode.tasksUsage).toStrictEqual({
-        run: max * maxMultiplier,
-        running: 0,
-        runTime: expect.any(Number),
-        runTimeHistory: expect.any(CircularArray),
-        avgRunTime: expect.any(Number),
-        medRunTime: 0,
-        waitTime: 0,
-        waitTimeHistory: expect.any(CircularArray),
-        avgWaitTime: 0,
-        medWaitTime: 0,
-        error: 0
+      expect(workerNode.usage).toMatchObject({
+        tasks: {
+          executed: expect.any(Number),
+          executing: 0,
+          queued: 0,
+          maxQueued: 0,
+          stolen: 0,
+          failed: 0
+        },
+        runTime: {
+          history: expect.any(CircularArray)
+        },
+        waitTime: {
+          history: expect.any(CircularArray)
+        },
+        elu: {
+          idle: {
+            history: expect.any(CircularArray)
+          },
+          active: {
+            history: expect.any(CircularArray)
+          }
+        }
       })
-      expect(workerNode.tasksUsage.avgRunTime).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeLessThanOrEqual(
+        max * maxMultiplier
+      )
+      if (workerNode.usage.runTime.aggregate == null) {
+        expect(workerNode.usage.runTime.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.runTime.aggregate).toBeGreaterThan(0)
+      }
+      if (workerNode.usage.runTime.average == null) {
+        expect(workerNode.usage.runTime.average).toBeUndefined()
+      } else {
+        expect(workerNode.usage.runTime.average).toBeGreaterThan(0)
+      }
+      if (workerNode.usage.elu.active.aggregate == null) {
+        expect(workerNode.usage.elu.active.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.elu.active.aggregate).toBeGreaterThan(0)
+      }
+      if (workerNode.usage.elu.idle.aggregate == null) {
+        expect(workerNode.usage.elu.idle.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.elu.idle.aggregate).toBeGreaterThanOrEqual(0)
+      }
+      if (workerNode.usage.elu.utilization == null) {
+        expect(workerNode.usage.elu.utilization).toBeUndefined()
+      } else {
+        expect(workerNode.usage.elu.utilization).toBeGreaterThanOrEqual(0)
+        expect(workerNode.usage.elu.utilization).toBeLessThanOrEqual(1)
+      }
     }
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
@@ -503,30 +1232,72 @@ describe('Selection strategies test suite', () => {
       {
         workerChoiceStrategy: WorkerChoiceStrategies.FAIR_SHARE,
         workerChoiceStrategyOptions: {
-          medRunTime: true
+          runTime: { median: true }
         }
       }
     )
     // TODO: Create a better test to cover `FairShareChoiceStrategy#choose`
+    const promises = new Set()
     const maxMultiplier = 2
     for (let i = 0; i < max * maxMultiplier; i++) {
-      await pool.execute()
+      promises.add(pool.execute())
     }
+    await Promise.all(promises)
     for (const workerNode of pool.workerNodes) {
-      expect(workerNode.tasksUsage).toStrictEqual({
-        run: max * maxMultiplier,
-        running: 0,
-        runTime: expect.any(Number),
-        runTimeHistory: expect.any(CircularArray),
-        avgRunTime: 0,
-        medRunTime: expect.any(Number),
-        waitTime: 0,
-        waitTimeHistory: expect.any(CircularArray),
-        avgWaitTime: 0,
-        medWaitTime: 0,
-        error: 0
+      expect(workerNode.usage).toMatchObject({
+        tasks: {
+          executed: expect.any(Number),
+          executing: 0,
+          queued: 0,
+          maxQueued: 0,
+          stolen: 0,
+          failed: 0
+        },
+        runTime: {
+          history: expect.any(CircularArray)
+        },
+        waitTime: {
+          history: expect.any(CircularArray)
+        },
+        elu: {
+          idle: {
+            history: expect.any(CircularArray)
+          },
+          active: {
+            history: expect.any(CircularArray)
+          }
+        }
       })
-      expect(workerNode.tasksUsage.medRunTime).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeLessThanOrEqual(
+        max * maxMultiplier
+      )
+      if (workerNode.usage.runTime.aggregate == null) {
+        expect(workerNode.usage.runTime.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.runTime.aggregate).toBeGreaterThan(0)
+      }
+      if (workerNode.usage.runTime.median == null) {
+        expect(workerNode.usage.runTime.median).toBeUndefined()
+      } else {
+        expect(workerNode.usage.runTime.median).toBeGreaterThan(0)
+      }
+      if (workerNode.usage.elu.active.aggregate == null) {
+        expect(workerNode.usage.elu.active.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.elu.active.aggregate).toBeGreaterThan(0)
+      }
+      if (workerNode.usage.elu.idle.aggregate == null) {
+        expect(workerNode.usage.elu.idle.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.elu.idle.aggregate).toBeGreaterThanOrEqual(0)
+      }
+      if (workerNode.usage.elu.utilization == null) {
+        expect(workerNode.usage.elu.utilization).toBeUndefined()
+      } else {
+        expect(workerNode.usage.elu.utilization).toBeGreaterThanOrEqual(0)
+        expect(workerNode.usage.elu.utilization).toBeLessThanOrEqual(1)
+      }
     }
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
@@ -611,7 +1382,33 @@ describe('Selection strategies test suite', () => {
     await pool.destroy()
   })
 
-  it('Verify WEIGHTED_ROUND_ROBIN strategy default tasks usage statistics requirements', async () => {
+  it('Verify WEIGHTED_ROUND_ROBIN strategy default policy', async () => {
+    const workerChoiceStrategy = WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
+    let pool = new FixedThreadPool(
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
+    expect(pool.workerChoiceStrategyContext.getStrategyPolicy()).toStrictEqual({
+      dynamicWorkerUsage: false,
+      dynamicWorkerReady: true
+    })
+    await pool.destroy()
+    pool = new DynamicThreadPool(
+      min,
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
+    expect(pool.workerChoiceStrategyContext.getStrategyPolicy()).toStrictEqual({
+      dynamicWorkerUsage: false,
+      dynamicWorkerReady: true
+    })
+    // We need to clean up the resources after our test
+    await pool.destroy()
+  })
+
+  it('Verify WEIGHTED_ROUND_ROBIN strategy default tasks statistics requirements', async () => {
     const workerChoiceStrategy = WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN
     let pool = new FixedThreadPool(
       max,
@@ -619,14 +1416,23 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy }
     )
     expect(
-      pool.workerChoiceStrategyContext.getRequiredStatistics()
+      pool.workerChoiceStrategyContext.getTaskStatisticsRequirements()
     ).toStrictEqual({
-      runTime: true,
-      avgRunTime: true,
-      medRunTime: false,
-      waitTime: false,
-      avgWaitTime: false,
-      medWaitTime: false
+      runTime: {
+        aggregate: true,
+        average: true,
+        median: false
+      },
+      waitTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      elu: {
+        aggregate: false,
+        average: false,
+        median: false
+      }
     })
     await pool.destroy()
     pool = new DynamicThreadPool(
@@ -636,14 +1442,23 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy }
     )
     expect(
-      pool.workerChoiceStrategyContext.getRequiredStatistics()
+      pool.workerChoiceStrategyContext.getTaskStatisticsRequirements()
     ).toStrictEqual({
-      runTime: true,
-      avgRunTime: true,
-      medRunTime: false,
-      waitTime: false,
-      avgWaitTime: false,
-      medWaitTime: false
+      runTime: {
+        aggregate: true,
+        average: true,
+        median: false
+      },
+      waitTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      elu: {
+        aggregate: false,
+        average: false,
+        median: false
+      }
     })
     // We need to clean up the resources after our test
     await pool.destroy()
@@ -656,27 +1471,51 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN }
     )
     // TODO: Create a better test to cover `WeightedRoundRobinWorkerChoiceStrategy#choose`
+    const promises = new Set()
     const maxMultiplier = 2
     for (let i = 0; i < max * maxMultiplier; i++) {
-      await pool.execute()
+      promises.add(pool.execute())
     }
+    await Promise.all(promises)
     for (const workerNode of pool.workerNodes) {
-      expect(workerNode.tasksUsage).toStrictEqual({
-        // FIXME: it should be:
-        // run: max * maxMultiplier,
-        run: expect.any(Number),
-        running: 0,
-        runTime: expect.any(Number),
-        runTimeHistory: expect.any(CircularArray),
-        avgRunTime: expect.any(Number),
-        medRunTime: 0,
-        waitTime: 0,
-        waitTimeHistory: expect.any(CircularArray),
-        avgWaitTime: 0,
-        medWaitTime: 0,
-        error: 0
+      expect(workerNode.usage).toStrictEqual({
+        tasks: {
+          executed: expect.any(Number),
+          executing: 0,
+          queued: 0,
+          maxQueued: 0,
+          stolen: 0,
+          failed: 0
+        },
+        runTime: expect.objectContaining({
+          history: expect.any(CircularArray)
+        }),
+        waitTime: {
+          history: expect.any(CircularArray)
+        },
+        elu: {
+          idle: {
+            history: expect.any(CircularArray)
+          },
+          active: {
+            history: expect.any(CircularArray)
+          }
+        }
       })
-      expect(workerNode.tasksUsage.avgRunTime).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeLessThanOrEqual(
+        max * maxMultiplier
+      )
+      if (workerNode.usage.runTime.aggregate == null) {
+        expect(workerNode.usage.runTime.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.runTime.aggregate).toBeGreaterThan(0)
+      }
+      if (workerNode.usage.runTime.average == null) {
+        expect(workerNode.usage.runTime.average).toBeUndefined()
+      } else {
+        expect(workerNode.usage.runTime.average).toBeGreaterThan(0)
+      }
     }
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
@@ -700,25 +1539,51 @@ describe('Selection strategies test suite', () => {
       { workerChoiceStrategy: WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN }
     )
     // TODO: Create a better test to cover `WeightedRoundRobinWorkerChoiceStrategy#choose`
+    const promises = new Set()
     const maxMultiplier = 2
     for (let i = 0; i < max * maxMultiplier; i++) {
-      await pool.execute()
+      promises.add(pool.execute())
     }
+    await Promise.all(promises)
     for (const workerNode of pool.workerNodes) {
-      expect(workerNode.tasksUsage).toStrictEqual({
-        run: max * maxMultiplier,
-        running: 0,
-        runTime: expect.any(Number),
-        runTimeHistory: expect.any(CircularArray),
-        avgRunTime: expect.any(Number),
-        medRunTime: 0,
-        waitTime: 0,
-        waitTimeHistory: expect.any(CircularArray),
-        avgWaitTime: 0,
-        medWaitTime: 0,
-        error: 0
+      expect(workerNode.usage).toStrictEqual({
+        tasks: {
+          executed: expect.any(Number),
+          executing: 0,
+          queued: 0,
+          maxQueued: 0,
+          stolen: 0,
+          failed: 0
+        },
+        runTime: expect.objectContaining({
+          history: expect.any(CircularArray)
+        }),
+        waitTime: {
+          history: expect.any(CircularArray)
+        },
+        elu: {
+          idle: {
+            history: expect.any(CircularArray)
+          },
+          active: {
+            history: expect.any(CircularArray)
+          }
+        }
       })
-      expect(workerNode.tasksUsage.avgRunTime).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeLessThanOrEqual(
+        max * maxMultiplier
+      )
+      if (workerNode.usage.runTime.aggregate == null) {
+        expect(workerNode.usage.runTime.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.runTime.aggregate).toBeGreaterThan(0)
+      }
+      if (workerNode.usage.runTime.average == null) {
+        expect(workerNode.usage.runTime.average).toBeUndefined()
+      } else {
+        expect(workerNode.usage.runTime.average).toBeGreaterThan(0)
+      }
     }
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
@@ -742,30 +1607,56 @@ describe('Selection strategies test suite', () => {
       {
         workerChoiceStrategy: WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN,
         workerChoiceStrategyOptions: {
-          medRunTime: true
+          runTime: { median: true }
         }
       }
     )
     // TODO: Create a better test to cover `WeightedRoundRobinWorkerChoiceStrategy#choose`
+    const promises = new Set()
     const maxMultiplier = 2
     for (let i = 0; i < max * maxMultiplier; i++) {
-      await pool.execute()
+      promises.add(pool.execute())
     }
+    await Promise.all(promises)
     for (const workerNode of pool.workerNodes) {
-      expect(workerNode.tasksUsage).toStrictEqual({
-        run: max * maxMultiplier,
-        running: 0,
-        runTime: expect.any(Number),
-        runTimeHistory: expect.any(CircularArray),
-        avgRunTime: 0,
-        medRunTime: expect.any(Number),
-        waitTime: 0,
-        waitTimeHistory: expect.any(CircularArray),
-        avgWaitTime: 0,
-        medWaitTime: 0,
-        error: 0
+      expect(workerNode.usage).toStrictEqual({
+        tasks: {
+          executed: expect.any(Number),
+          executing: 0,
+          queued: 0,
+          maxQueued: 0,
+          stolen: 0,
+          failed: 0
+        },
+        runTime: expect.objectContaining({
+          history: expect.any(CircularArray)
+        }),
+        waitTime: {
+          history: expect.any(CircularArray)
+        },
+        elu: {
+          idle: {
+            history: expect.any(CircularArray)
+          },
+          active: {
+            history: expect.any(CircularArray)
+          }
+        }
       })
-      expect(workerNode.tasksUsage.medRunTime).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeLessThanOrEqual(
+        max * maxMultiplier
+      )
+      if (workerNode.usage.runTime.aggregate == null) {
+        expect(workerNode.usage.runTime.aggregate).toBeUndefined()
+      } else {
+        expect(workerNode.usage.runTime.aggregate).toBeGreaterThan(0)
+      }
+      if (workerNode.usage.runTime.median == null) {
+        expect(workerNode.usage.runTime.median).toBeUndefined()
+      } else {
+        expect(workerNode.usage.runTime.median).toBeGreaterThan(0)
+      }
     }
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
@@ -790,7 +1681,7 @@ describe('Selection strategies test suite', () => {
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
         workerChoiceStrategy
-      ).currentWorkerNodeId
+      ).nextWorkerNodeKey
     ).toBeDefined()
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
@@ -806,7 +1697,7 @@ describe('Selection strategies test suite', () => {
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
         pool.workerChoiceStrategyContext.workerChoiceStrategy
-      ).currentWorkerNodeId
+      ).nextWorkerNodeKey
     ).toBe(0)
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
@@ -827,7 +1718,7 @@ describe('Selection strategies test suite', () => {
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
         workerChoiceStrategy
-      ).currentWorkerNodeId
+      ).nextWorkerNodeKey
     ).toBeDefined()
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
@@ -843,7 +1734,7 @@ describe('Selection strategies test suite', () => {
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
         pool.workerChoiceStrategyContext.workerChoiceStrategy
-      ).currentWorkerNodeId
+      ).nextWorkerNodeKey
     ).toBe(0)
     expect(
       pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
@@ -859,6 +1750,337 @@ describe('Selection strategies test suite', () => {
     await pool.destroy()
   })
 
+  it('Verify INTERLEAVED_WEIGHTED_ROUND_ROBIN strategy default policy', async () => {
+    const workerChoiceStrategy =
+      WorkerChoiceStrategies.INTERLEAVED_WEIGHTED_ROUND_ROBIN
+    let pool = new FixedThreadPool(
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
+    expect(pool.workerChoiceStrategyContext.getStrategyPolicy()).toStrictEqual({
+      dynamicWorkerUsage: false,
+      dynamicWorkerReady: true
+    })
+    await pool.destroy()
+    pool = new DynamicThreadPool(
+      min,
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
+    expect(pool.workerChoiceStrategyContext.getStrategyPolicy()).toStrictEqual({
+      dynamicWorkerUsage: false,
+      dynamicWorkerReady: true
+    })
+    // We need to clean up the resources after our test
+    await pool.destroy()
+  })
+
+  it('Verify INTERLEAVED_WEIGHTED_ROUND_ROBIN strategy default tasks statistics requirements', async () => {
+    const workerChoiceStrategy =
+      WorkerChoiceStrategies.INTERLEAVED_WEIGHTED_ROUND_ROBIN
+    let pool = new FixedThreadPool(
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
+    expect(
+      pool.workerChoiceStrategyContext.getTaskStatisticsRequirements()
+    ).toStrictEqual({
+      runTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      waitTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      elu: {
+        aggregate: false,
+        average: false,
+        median: false
+      }
+    })
+    await pool.destroy()
+    pool = new DynamicThreadPool(
+      min,
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      { workerChoiceStrategy }
+    )
+    expect(
+      pool.workerChoiceStrategyContext.getTaskStatisticsRequirements()
+    ).toStrictEqual({
+      runTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      waitTime: {
+        aggregate: false,
+        average: false,
+        median: false
+      },
+      elu: {
+        aggregate: false,
+        average: false,
+        median: false
+      }
+    })
+    // We need to clean up the resources after our test
+    await pool.destroy()
+  })
+
+  it('Verify INTERLEAVED_WEIGHTED_ROUND_ROBIN strategy can be run in a fixed pool', async () => {
+    const pool = new FixedThreadPool(
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      {
+        workerChoiceStrategy:
+          WorkerChoiceStrategies.INTERLEAVED_WEIGHTED_ROUND_ROBIN
+      }
+    )
+    // TODO: Create a better test to cover `InterleavedWeightedRoundRobinWorkerChoiceStrategy#choose`
+    const promises = new Set()
+    const maxMultiplier = 2
+    for (let i = 0; i < max * maxMultiplier; i++) {
+      promises.add(pool.execute())
+    }
+    await Promise.all(promises)
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.usage).toStrictEqual({
+        tasks: {
+          executed: maxMultiplier,
+          executing: 0,
+          queued: 0,
+          maxQueued: 0,
+          stolen: 0,
+          failed: 0
+        },
+        runTime: {
+          history: expect.any(CircularArray)
+        },
+        waitTime: {
+          history: expect.any(CircularArray)
+        },
+        elu: {
+          idle: {
+            history: expect.any(CircularArray)
+          },
+          active: {
+            history: expect.any(CircularArray)
+          }
+        }
+      })
+    }
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).defaultWorkerWeight
+    ).toBeGreaterThan(0)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).roundId
+    ).toBe(0)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).nextWorkerNodeKey
+    ).toBe(0)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).roundWeights
+    ).toStrictEqual([
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).defaultWorkerWeight
+    ])
+    // We need to clean up the resources after our test
+    await pool.destroy()
+  })
+
+  it('Verify INTERLEAVED_WEIGHTED_ROUND_ROBIN strategy can be run in a dynamic pool', async () => {
+    const pool = new DynamicThreadPool(
+      min,
+      max,
+      './tests/worker-files/thread/testWorker.js',
+      {
+        workerChoiceStrategy:
+          WorkerChoiceStrategies.INTERLEAVED_WEIGHTED_ROUND_ROBIN
+      }
+    )
+    // TODO: Create a better test to cover `InterleavedWeightedRoundRobinWorkerChoiceStrategy#choose`
+    const promises = new Set()
+    const maxMultiplier = 2
+    for (let i = 0; i < max * maxMultiplier; i++) {
+      promises.add(pool.execute())
+    }
+    await Promise.all(promises)
+    for (const workerNode of pool.workerNodes) {
+      expect(workerNode.usage).toStrictEqual({
+        tasks: {
+          executed: expect.any(Number),
+          executing: 0,
+          queued: 0,
+          maxQueued: 0,
+          stolen: 0,
+          failed: 0
+        },
+        runTime: {
+          history: expect.any(CircularArray)
+        },
+        waitTime: {
+          history: expect.any(CircularArray)
+        },
+        elu: {
+          idle: {
+            history: expect.any(CircularArray)
+          },
+          active: {
+            history: expect.any(CircularArray)
+          }
+        }
+      })
+      expect(workerNode.usage.tasks.executed).toBeGreaterThanOrEqual(0)
+      expect(workerNode.usage.tasks.executed).toBeLessThanOrEqual(
+        max * maxMultiplier
+      )
+    }
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).defaultWorkerWeight
+    ).toBeGreaterThan(0)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).roundId
+    ).toBe(0)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).nextWorkerNodeKey
+    ).toBe(0)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).roundWeights
+    ).toStrictEqual([
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).defaultWorkerWeight
+    ])
+    // We need to clean up the resources after our test
+    await pool.destroy()
+  })
+
+  it('Verify INTERLEAVED_WEIGHTED_ROUND_ROBIN strategy internals are resets after setting it', async () => {
+    const workerChoiceStrategy =
+      WorkerChoiceStrategies.INTERLEAVED_WEIGHTED_ROUND_ROBIN
+    let pool = new FixedThreadPool(
+      max,
+      './tests/worker-files/thread/testWorker.js'
+    )
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).roundId
+    ).toBeDefined()
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).nextWorkerNodeKey
+    ).toBeDefined()
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).defaultWorkerWeight
+    ).toBeDefined()
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).roundWeights
+    ).toBeDefined()
+    pool.setWorkerChoiceStrategy(workerChoiceStrategy)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).roundId
+    ).toBe(0)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).nextWorkerNodeKey
+    ).toBe(0)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).defaultWorkerWeight
+    ).toBeGreaterThan(0)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).roundWeights
+    ).toStrictEqual([
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).defaultWorkerWeight
+    ])
+    await pool.destroy()
+    pool = new DynamicThreadPool(
+      min,
+      max,
+      './tests/worker-files/thread/testWorker.js'
+    )
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).roundId
+    ).toBeDefined()
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).nextWorkerNodeKey
+    ).toBeDefined()
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).defaultWorkerWeight
+    ).toBeDefined()
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).roundWeights
+    ).toBeDefined()
+    pool.setWorkerChoiceStrategy(workerChoiceStrategy)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).nextWorkerNodeKey
+    ).toBe(0)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).defaultWorkerWeight
+    ).toBeGreaterThan(0)
+    expect(
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        workerChoiceStrategy
+      ).roundWeights
+    ).toStrictEqual([
+      pool.workerChoiceStrategyContext.workerChoiceStrategies.get(
+        pool.workerChoiceStrategyContext.workerChoiceStrategy
+      ).defaultWorkerWeight
+    ])
+    // We need to clean up the resources after our test
+    await pool.destroy()
+  })
+
   it('Verify unknown strategy throw error', () => {
     expect(
       () =>