diff --git a/src/fixed-queue.ts b/src/fixed-queue.ts
index 2bc2a4af..30053b0c 100644
--- a/src/fixed-queue.ts
+++ b/src/fixed-queue.ts
@@ -63,28 +63,25 @@ class FixedCircularBuffer {
   top: number
   list: Array<Task | undefined>
   next: FixedCircularBuffer | null
-  _size: number
 
   constructor () {
     this.bottom = 0;
     this.top = 0;
     this.list = new Array(kSize);
     this.next = null;
-    this._size = 0;
   }
 
   isEmpty () {
-    return this.top === this.bottom && this._size === 0;
+    return this.top === this.bottom;
   }
 
   isFull () {
-    return this.top === this.bottom && this._size === kSize;
+    return ((this.top + 1) & kMask) === this.bottom;
   }
 
   push (data:Task) {
     this.list[this.top] = data;
     this.top = (this.top + 1) & kMask;
-    this._size++;
   }
 
   shift () {
@@ -92,7 +89,6 @@ class FixedCircularBuffer {
     if (nextItem === undefined) { return null; }
     this.list[this.bottom] = undefined;
     this.bottom = (this.bottom + 1) & kMask;
-    this._size--;
     return nextItem;
   }
 
@@ -114,7 +110,6 @@ class FixedCircularBuffer {
       curr = next;
     }
     this.top = (this.top - 1) & kMask;
-    this._size--;
   }
 }
 
diff --git a/test/fixed-queue.ts b/test/fixed-queue.ts
index 085e0132..782ffb30 100644
--- a/test/fixed-queue.ts
+++ b/test/fixed-queue.ts
@@ -63,9 +63,19 @@ test('remove not queued task should not lead to errors', async ({ equal }) => {
 });
 
 test('removing elements from intermediate CircularBuffer should not lead to issues', async ({ equal, same }) => {
+  /*
+      The test intends to check following scenario:
+      1) We fill the queue with 3 full circular buffers amount of items.
+      2) Empty the middle circular buffer with remove().
+      3) This should lead to the removal of the middle buffer from the queue:
+         - Before emptying: tail buffer -> middle buffer -> head buffer.
+         - After emptying: tail buffer -> head buffer.
+   */
+
   const queue = new FixedQueue();
 
-  const batchSize = 2048;
+  // size of single circular buffer
+  const batchSize = 2047;
 
   const firstBatch = Array.from({ length: batchSize }, () => new QueueTask());
   const secondBatch = Array.from({ length: batchSize }, () => new QueueTask());
@@ -94,9 +104,18 @@ test('removing elements from intermediate CircularBuffer should not lead to issu
 });
 
 test('removing elements from first CircularBuffer should not lead to issues', async ({ equal, same }) => {
+  /*
+      The test intends to check following scenario:
+      1) We fill the queue with 3 full circular buffers amount of items.
+      2) Empty the first circular buffer with remove().
+      3) This should lead to the removal of the tail buffer from the queue:
+         - Before emptying: tail buffer -> middle buffer -> head buffer.
+         - After emptying: tail buffer (previously middle) -> head buffer.
+   */
   const queue = new FixedQueue();
 
-  const batchSize = 2048;
+  // size of single circular buffer
+  const batchSize = 2047;
 
   const firstBatch = Array.from({ length: batchSize }, () => new QueueTask());
   const secondBatch = Array.from({ length: batchSize }, () => new QueueTask());
@@ -125,9 +144,18 @@ test('removing elements from first CircularBuffer should not lead to issues', as
 });
 
 test('removing elements from last CircularBuffer should not lead to issues', async ({ equal, same }) => {
+  /*
+      The test intends to check following scenario:
+      1) We fill the queue with 3 full circular buffers amount of items.
+      2) Empty the last circular buffer with remove().
+      3) This should lead to the removal of the head buffer from the queue:
+         - Before emptying: tail buffer -> middle buffer -> head buffer.
+         - After emptying: tail buffer -> head buffer (previously middle).
+   */
   const queue = new FixedQueue();
 
-  const batchSize = 2048;
+  // size of single circular buffer
+  const batchSize = 2047;
 
   const firstBatch = Array.from({ length: batchSize }, () => new QueueTask());
   const secondBatch = Array.from({ length: batchSize }, () => new QueueTask());