diff --git a/test/unit/EventAccumulator.test.ts b/test/unit/EventAccumulator.test.ts
new file mode 100644
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--- /dev/null
+++ b/test/unit/EventAccumulator.test.ts
@@ -0,0 +1,153 @@
+/* eslint-disable no-console */
+import { expect } from 'chai'
+import Countly from 'countly-sdk-nodejs'
+import Sinon from 'sinon'
+import { EventAccumulator } from '../../src/EventAccumulator.js'
+
+const sleep = async (ms: number): Promise<unknown> => await new Promise(resolve => setTimeout(resolve, ms))
+
+describe('EventAccumulator', () => {
+  it('should accumulate events', async () => {
+    Countly.add_event = Sinon.stub()
+    const accumulator = new EventAccumulator(Countly)
+    const event = {
+      key: 'test',
+      count: 1,
+      sum: 1,
+      segmentation: {}
+    }
+    // add the event twice with a 100ms delay between them, this is needed to test the duration.
+    accumulator.addEvent(event)
+    await sleep(100)
+    accumulator.addEvent(event)
+    // flush the event
+    accumulator.flush('test')
+    // check the event data
+    const { count, dur, key, sum, segmentation } = Countly.add_event.getCall(0).args[0]
+    expect(count).to.be.equal(2)
+    expect(dur).to.be.greaterThan(100)
+    expect(key).to.be.equal('test')
+    expect(sum).to.be.equal(2)
+    expect(segmentation).to.be.deep.equal({})
+    expect(Countly.add_event.callCount).to.be.equal(1)
+  })
+
+  it('should flush events after the flush interval', async () => {
+    Countly.add_event = Sinon.stub()
+    const accumulator = new EventAccumulator(Countly, 100)
+    const event = {
+      key: 'test',
+      count: 1,
+      sum: 1,
+      segmentation: {}
+    }
+    accumulator.addEvent(event)
+    // wait for the flush interval to pass
+    await sleep(150)
+    // check the event data
+    const { count, dur, key, sum, segmentation } = Countly.add_event.getCall(0).args[0]
+    expect(count).to.be.equal(1)
+    expect(dur).to.be.greaterThanOrEqual(100)
+    expect(key).to.be.equal('test')
+    expect(sum).to.be.equal(1)
+    expect(segmentation).to.be.deep.equal({})
+    expect(Countly.add_event.callCount).to.be.equal(1)
+  })
+
+  it('should flush events when flush=true', async () => {
+    Countly.add_event = Sinon.stub()
+    const accumulator = new EventAccumulator(Countly, 1000)
+    const event = {
+      key: 'test',
+      count: 1,
+      sum: 1,
+      segmentation: {}
+    }
+    // add the event twice with a 100ms delay between them, this is needed to test the duration.
+    accumulator.addEvent(event)
+    await sleep(100)
+    accumulator.addEvent(event, true)
+    // check the event data
+    const { count, dur, key, sum, segmentation } = Countly.add_event.getCall(0).args[0]
+    expect(count).to.be.equal(2)
+    expect(dur).to.be.greaterThanOrEqual(100)
+    expect(key).to.be.equal('test')
+    expect(sum).to.be.equal(2)
+    expect(segmentation).to.be.deep.equal({})
+    expect(Countly.add_event.callCount).to.be.equal(1)
+  })
+
+  it('should accumulate segments', async () => {
+    Countly.add_event = Sinon.stub()
+    const accumulator = new EventAccumulator(Countly, 1000)
+    const event1 = {
+      key: 'test',
+      count: 1,
+      sum: 1,
+      segmentation: {
+        foo: 'bar'
+      }
+    }
+    const event2 = {
+      key: 'test',
+      count: 1,
+      sum: 1,
+      segmentation: {
+        bar: 'baz'
+      }
+    }
+    // add the event twice with a 100ms delay between them, this is needed to test the duration.
+    accumulator.addEvent(event1)
+    await sleep(100)
+    accumulator.addEvent(event2, true)
+    // check the event data
+    const { count, dur, key, sum, segmentation } = Countly.add_event.getCall(0).args[0]
+    expect(count).to.be.equal(2)
+    expect(dur).to.be.greaterThanOrEqual(100)
+    expect(key).to.be.equal('test')
+    expect(sum).to.be.equal(2)
+    expect(segmentation).to.be.deep.equal({
+      foo: 'bar',
+      bar: 'baz'
+    })
+    expect(Countly.add_event.callCount).to.be.equal(1)
+  })
+
+  it('should accumulate different types of events', async () => {
+    Countly.add_event = Sinon.stub()
+    const accumulator = new EventAccumulator(Countly, 100)
+    const event1 = {
+      key: 'test1',
+      count: 1,
+      sum: 1,
+      segmentation: {
+        foo: 'bar'
+      }
+    }
+    const event2 = {
+      key: 'test2',
+      count: 1,
+      sum: 1,
+      segmentation: {
+        bar: 'baz'
+      }
+    }
+    accumulator.addEvent(event1)
+    // adding the second event after 50ms so that the first event is flushed first
+    await sleep(50)
+    accumulator.addEvent(event2)
+    // wait for the flush interval to pass
+    await sleep(150)
+    // check the event data
+    const calls = [['test1', { foo: 'bar' }], ['test2', { bar: 'baz' }]]
+    calls.forEach(([testKey, segment], idx) => {
+      const { count, dur, key, sum, segmentation } = Countly.add_event.getCall(idx).args[0]
+      expect(count).to.be.equal(1)
+      expect(dur).to.be.greaterThanOrEqual(100)
+      expect(key).to.be.equal(testKey)
+      expect(sum).to.be.equal(1)
+      expect(segmentation).to.be.deep.equals(segment)
+    })
+    expect(Countly.add_event.callCount).to.be.equal(2)
+  })
+})