diff --git a/src/Containers-Queue-Tests/CTQueueTest.class.st b/src/Containers-Queue-Tests/CTQueueTest.class.st
index 6d1149e..aa8a6bd 100644
--- a/src/Containers-Queue-Tests/CTQueueTest.class.st
+++ b/src/Containers-Queue-Tests/CTQueueTest.class.st
@@ -3,17 +3,18 @@ I'm a simple queue i.e., first in first out structure.
 I support basic collection protocol and in addition enqueue and dequeue as in Scala. 
 "
 Class {
-	#name : #CTQueueTest,
-	#superclass : #TestCase,
-	#category : #'Containers-Queue-Tests'
+	#name : 'CTQueueTest',
+	#superclass : 'TestCase',
+	#category : 'Containers-Queue-Tests',
+	#package : 'Containers-Queue-Tests'
 }
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> queueClass [
 	^ CTQueue
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testAdd [
 	| queue |
 	queue := self queueClass new.
@@ -23,7 +24,7 @@ CTQueueTest >> testAdd [
 	self assert: (queue includes: 2)
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testAddAll [
 	"Ensure queueAll adds multiple elements at once."
 	| queue |
@@ -35,7 +36,7 @@ CTQueueTest >> testAddAll [
 	self assert: queue remove equals: 40.
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testAddAllLargeCollection [
 	"Test adding a large collection via addAll."
 	| queue collection size |
@@ -48,7 +49,7 @@ CTQueueTest >> testAddAllLargeCollection [
 	self assert: queue isEmpty.
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testAddGarantyFIFOOrder [
 	"Ensure elements are dequeued in FIFO order."
 	| queue |
@@ -62,7 +63,7 @@ CTQueueTest >> testAddGarantyFIFOOrder [
 	self assert: queue isEmpty.
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testAddNilElement [
 	"Test adding a nil element to the queue."
 	| queue |
@@ -74,7 +75,28 @@ CTQueueTest >> testAddNilElement [
 	self assert: queue isEmpty.
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
+CTQueueTest >> testAddUnless [
+	| queue |
+	queue := self queueClass new.
+	queue add: 1 unless: [ :v | (v rem: 2) = 0].
+	self assert: (queue includes: 1).
+	self assert: queue size equals: 1 .
+	queue add: 2 unless: [ :v | (v rem: 2) = 0].
+	self assert: (queue includes: 1).
+	self assert: (queue includes: 2) .
+	self assert: queue size equals: 2 .
+	queue add: 4 unless: [ :v | (v rem: 2) = 0].
+	self assert: (queue includes: 1).
+	self assert: (queue includes: 2) .
+	self assert: queue size equals: 2 .
+	queue add: 3 unless: [ :v | (v rem: 2) = 0].
+	self assert: (queue includes: 1).
+	self assert: (queue includes: 2) .
+	self assert: queue size equals: 2
+]
+
+{ #category : 'tests' }
 CTQueueTest >> testDoIteration [
 	"Test iterating over the queue with do: in FIFO order."
 	| queue collected |
@@ -86,19 +108,19 @@ CTQueueTest >> testDoIteration [
 	self assert: queue size equals: 4. "Iteration should not modify the queue"
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testEmptyQueue [
 	self assert: self queueClass new isEmpty
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testEmptyQueueRemove [
 	| queue |
 	queue := self queueClass new.
 	self assert: queue remove isNil.
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testIncludes [
 	"Test the includes: method for existing and non-existing elements."
 	| queue |
@@ -109,7 +131,7 @@ CTQueueTest >> testIncludes [
 	self assert: queue size equals: 3. "includes: should not modify the queue"
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testInterleavedAddRemove [
 	"Test interleaved add and remove operations to ensure FIFO order and correctness."
 	| queue |
@@ -125,7 +147,7 @@ CTQueueTest >> testInterleavedAddRemove [
 	self assert: queue isEmpty.
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testIsEmpty [
 	"Ensure isEmpty works correctly."
 	| queue |
@@ -137,7 +159,7 @@ CTQueueTest >> testIsEmpty [
 	self assert: queue isEmpty.
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testLargeQueuePerformance [
 	"Verify FIFO behavior and performance with a large queue."
 	| queue size startTime endTime duration maxDuration |
@@ -162,7 +184,7 @@ CTQueueTest >> testLargeQueuePerformance [
 	self assert: queue isEmpty.
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testPeek [
 	"Ensure peek returns the first element without removing it."
 	| queue |
@@ -173,7 +195,7 @@ CTQueueTest >> testPeek [
 	self assert: queue size equals: 2. "Peek should not remove elements"
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testPoll [
 	"Ensure poll behaves correctly, returning nil when empty."
 	| queue |
@@ -185,17 +207,17 @@ CTQueueTest >> testPoll [
 	self assert: queue poll isNil.
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testQueue [
 	self assert: self queueClass new isEmpty
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testQueueGarantyFIFOOrder [
 	self assert: self queueClass new isEmpty
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testRemove [
 	"Ensure remove behaves correctly, returning nil when empty."
 	| queue |
@@ -207,7 +229,7 @@ CTQueueTest >> testRemove [
 	self assert: queue remove equals: 2
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testRemoveIfNone [
 	"Ensure removeIfNone works correctly."
 	| queue result |
@@ -216,7 +238,7 @@ CTQueueTest >> testRemoveIfNone [
 	self assert: result equals: 'fallback'.
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testSizeAccuracy [
 	"Test that the size method accurately reflects the number of elements."
 	| queue |
@@ -232,7 +254,7 @@ CTQueueTest >> testSizeAccuracy [
 	self assert: queue size equals: 2.
 ]
 
-{ #category : #tests }
+{ #category : 'tests' }
 CTQueueTest >> testStressAddRemove [
 	"Stress test with many add and remove operations."
 	| queue iterations |
@@ -248,4 +270,4 @@ CTQueueTest >> testStressAddRemove [
 	queue addAll: (1 to: 1000).
 	1 to: 1000 do: [ :i | self assert: queue remove equals: i ].
 	self assert: queue isEmpty.
-]
\ No newline at end of file
+]
diff --git a/src/Containers-Queue-Tests/package.st b/src/Containers-Queue-Tests/package.st
index ccf49f0..c9e25b5 100644
--- a/src/Containers-Queue-Tests/package.st
+++ b/src/Containers-Queue-Tests/package.st
@@ -1 +1 @@
-Package { #name : #'Containers-Queue-Tests' }
+Package { #name : 'Containers-Queue-Tests' }
diff --git a/src/Containers-Queue/CTQueue.class.st b/src/Containers-Queue/CTQueue.class.st
index 2baf9bb..7f213fa 100644
--- a/src/Containers-Queue/CTQueue.class.st
+++ b/src/Containers-Queue/CTQueue.class.st
@@ -2,17 +2,18 @@
 I'm a simple FIFO queue i.e., first in first out structure. I support basic collection protocol with efficient O(1) add and remove operations using a singly linked list.
 "
 Class {
-	#name : #CTQueue,
-	#superclass : #Object,
+	#name : 'CTQueue',
+	#superclass : 'Object',
 	#instVars : [
 		'head',
 		'tail',
 		'size'
 	],
-	#category : #'Containers-Queue'
+	#category : 'Containers-Queue',
+	#package : 'Containers-Queue'
 }
 
-{ #category : #adding }
+{ #category : 'adding' }
 CTQueue >> add: anElement [
 	"Add an element to the end of the queue (FIFO order)."
 	| newNode |
@@ -28,14 +29,39 @@ CTQueue >> add: anElement [
 	^ anElement
 ]
 
-{ #category : #adding }
+{ #category : 'adding' }
+CTQueue >> add: anElement unless: aTestIsTrue [
+	"Add an element to the end of the queue (FIFO order)."
+	| newNode |
+
+	head ifNil: [ 
+		newNode := CTQueueNode new value: anElement.
+		head := newNode.
+		tail := newNode.
+	] ifNotNil: [ 
+		|current|
+		current := head .
+		[ current = tail ] whileFalse: [ 
+			(aTestIsTrue value: current value) ifTrue: [ ^ current value ] .
+			current := current next
+		 ] .
+		(aTestIsTrue value: tail value) ifTrue: [ ^ tail value ] .
+		newNode := CTQueueNode new value: anElement.
+		tail next: newNode.
+		tail := newNode.
+	].
+	size := size + 1.
+	^ anElement
+]
+
+{ #category : 'adding' }
 CTQueue >> addAll: aCollection [
 	"Add all elements from aCollection to the end of the queue."
 	aCollection do: [ :each | self add: each ].
 	^ aCollection
 ]
 
-{ #category : #iterating }
+{ #category : 'iterating' }
 CTQueue >> do: aBlock [
 	"Iterate over elements in FIFO order."
 	| current |
@@ -46,7 +72,7 @@ CTQueue >> do: aBlock [
 	]
 ]
 
-{ #category : #testing }
+{ #category : 'testing' }
 CTQueue >> includes: anElement [
 	"Check if anElement exists in the queue."
 	| current |
@@ -58,7 +84,7 @@ CTQueue >> includes: anElement [
 	^ false
 ]
 
-{ #category : #initialization }
+{ #category : 'initialization' }
 CTQueue >> initialize [
 	"Initialize an empty queue."
 	super initialize.
@@ -67,25 +93,25 @@ CTQueue >> initialize [
 	size := 0.
 ]
 
-{ #category : #testing }
+{ #category : 'testing' }
 CTQueue >> isEmpty [
 	"Return true if the queue is empty."
 	^ head isNil
 ]
 
-{ #category : #accessing }
+{ #category : 'accessing' }
 CTQueue >> peek [
 	"Return the front element without removing it, or nil if empty."
 	^ head ifNil: [ nil ] ifNotNil: [ head value ]
 ]
 
-{ #category : #removing }
+{ #category : 'removing' }
 CTQueue >> poll [
 	"Return and remove the front element, or nil if empty."
 	^ self remove
 ]
 
-{ #category : #removing }
+{ #category : 'removing' }
 CTQueue >> remove [
 	"Return and remove the oldest element, or nil if empty."
 	| value |
@@ -97,15 +123,15 @@ CTQueue >> remove [
 	^ value
 ]
 
-{ #category : #removing }
+{ #category : 'removing' }
 CTQueue >> removeIfNone: aBlock [
 	"Return and remove the oldest element, or evaluate aBlock if empty."
 	head ifNil: [ ^ aBlock value ].
 	^ self remove
 ]
 
-{ #category : #accessing }
+{ #category : 'accessing' }
 CTQueue >> size [
 	"Return the number of elements in the queue."
 	^ size
-]
\ No newline at end of file
+]
diff --git a/src/Containers-Queue/CTQueueNode.class.st b/src/Containers-Queue/CTQueueNode.class.st
index 430c3b2..f72eaeb 100644
--- a/src/Containers-Queue/CTQueueNode.class.st
+++ b/src/Containers-Queue/CTQueueNode.class.st
@@ -1,29 +1,30 @@
 Class {
-	#name : #CTQueueNode,
-	#superclass : #Object,
+	#name : 'CTQueueNode',
+	#superclass : 'Object',
 	#instVars : [
 		'value',
 		'next'
 	],
-	#category : #'Containers-Queue'
+	#category : 'Containers-Queue',
+	#package : 'Containers-Queue'
 }
 
-{ #category : #accessing }
+{ #category : 'accessing' }
 CTQueueNode >> next [
 	^ next
 ]
 
-{ #category : #accessing }
+{ #category : 'accessing' }
 CTQueueNode >> next: aNode [
 	next := aNode
 ]
 
-{ #category : #accessing }
+{ #category : 'accessing' }
 CTQueueNode >> value [
 	^ value
 ]
 
-{ #category : #accessing }
+{ #category : 'accessing' }
 CTQueueNode >> value: anObject [
 	value := anObject
-]
\ No newline at end of file
+]
diff --git a/src/Containers-Queue/package.st b/src/Containers-Queue/package.st
index 500d4dd..bee4046 100644
--- a/src/Containers-Queue/package.st
+++ b/src/Containers-Queue/package.st
@@ -1 +1 @@
-Package { #name : #'Containers-Queue' }
+Package { #name : 'Containers-Queue' }