chore: add GlobalUsings.cs with project-wide using directives in data structures tests

DataStructures.Tests/AATreeTests.cs

@@ -1,9 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using DataStructures.AATree;
-using FluentAssertions;
-using NUnit.Framework;
 
 namespace DataStructures.Tests;
 

DataStructures.Tests/AVLTreeTests.cs

@@ -1,9 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using DataStructures.AVLTree;
-using FluentAssertions;
-using NUnit.Framework;
 using static FluentAssertions.FluentActions;
 
 namespace DataStructures.Tests;
@@ -233,19 +228,19 @@ public void Remove_MultipleKeys_TreeStillValid_Variant2()
         tree.GetKeysInOrder()
             .Should()
             .BeEquivalentTo(
-                new[] { 4,6,8 },
+                new[] { 4, 6, 8 },
                 config => config.WithStrictOrdering());
 
         tree.GetKeysPreOrder()
             .Should()
             .BeEquivalentTo(
-                new[] { 6,4,8 },
+                new[] { 6, 4, 8 },
                 config => config.WithStrictOrdering());
 
         tree.GetKeysPostOrder()
             .Should()
             .BeEquivalentTo(
-                new[] { 4,8,6 },
+                new[] { 4, 8, 6 },
                 config => config.WithStrictOrdering());
     }
 

DataStructures.Tests/BinarySearchTreeTests.cs

@@ -1,8 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using DataStructures.BinarySearchTree;
-using NUnit.Framework;
 
 namespace DataStructures.Tests;
 

DataStructures.Tests/BitArrayTests.cs

@@ -1,7 +1,3 @@
-using System;
-using FluentAssertions;
-using NUnit.Framework;
-
 namespace DataStructures.Tests;
 
 /// <summary>

DataStructures.Tests/Cache/LfuCacheTests.cs

@@ -1,6 +1,4 @@
 using DataStructures.Cache;
-using FluentAssertions;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.Cache;
 

DataStructures.Tests/Cache/LruCacheTests.cs

@@ -1,6 +1,4 @@
 using DataStructures.Cache;
-using FluentAssertions;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.Cache;
 

DataStructures.Tests/DisjointSet/DisjointSetTests.cs

@@ -1,6 +1,4 @@
 using DataStructures.DisjointSet;
-using FluentAssertions;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.DisjointSet;
 

DataStructures.Tests/Fenwick/BinaryIndexedTreeTests.cs

@@ -1,6 +1,4 @@
 using DataStructures.Fenwick;
-using FluentAssertions;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.Fenwick;
 

DataStructures.Tests/GlobalUsings.cs

@@ -0,0 +1,20 @@
+// -----------------------------------------------------------------------------
+// Global using directives for the C-Sharp solution.
+// These namespaces are imported globally so they don’t need to be repeatedly declared
+// in individual files, improving readability and reducing boilerplate.
+//
+// Guidelines:
+// - Keep only the most commonly used namespaces here.
+// - Add project-specific namespaces (e.g., Utilities.Extensions) only if they are
+//   required across the majority of files in the project.
+// - Avoid placing rarely used namespaces here to maintain clarity.
+// -----------------------------------------------------------------------------
+
+global using System;                        // Core base classes and fundamental types
+global using System.Collections.Generic;    // Generic collection types (List, Dictionary, etc.)
+global using System.Linq;                   // LINQ query operators for collections
+global using System.Text;                   // Text encoding, StringBuilder, etc.
+global using NUnit.Framework;               // Testing framework providing attributes and assertions for test cases
+global using NUnit.Framework.Internal;      // Internal NUnit infrastructure (test context, utilities) — generally used for advanced or framework-level test control
+global using FluentAssertions;              // Assertion library for more readable and expressive unit tests
+global using System.Collections;            // Non-generic collection types (e.g., ArrayList, Hashtable, IDictionary, ICollection)

DataStructures.Tests/Graph/DirectedWeightedGraphTests.cs

@@ -1,9 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using DataStructures.Graph;
-using FluentAssertions;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.Graph;
 

DataStructures.Tests/Hashing/HashTableTests.cs

@@ -1,8 +1,4 @@
-using System;
-using System.Collections.Generic;
 using DataStructures.Hashing;
-using FluentAssertions;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.Hashing;
 
@@ -275,7 +271,7 @@ public void Keys_ReturnsCorrectKeys()
         hashTable.Add(2, "two");
         hashTable.Add(3, "three");
 
-        var keys = new List<int> { 1,2,3 };
+        var keys = new List<int> { 1, 2, 3 };
 
         Assert.That(keys, Is.EquivalentTo(hashTable.Keys));
     }
@@ -377,10 +373,11 @@ public void This_Set_KeyNotFoundException_WhenKeyDoesNotExist()
     public void This_Get_KeyNotFoundException_WhenKeyDoesNotExist()
     {
         var hashTable = new HashTable<string, int>(4);
-        Assert.Throws<KeyNotFoundException>(() => {
+        Assert.Throws<KeyNotFoundException>(() =>
+        {
             var value = hashTable["one"];
             Console.WriteLine(value);
-             });
+        });
     }
 
     [Test]
@@ -409,7 +406,7 @@ public void Add_ShouldTriggerResize_WhenThresholdExceeded()
         hashTable.Count.Should().Be(4); // Verify count reflects number of added items
     }
 
-    
+
     [Test]
     public void Add_ThrowsException_WhenKeyIsDefault()
     {

DataStructures.Tests/Hashing/NumberTheory/PrimeNumberTests.cs

@@ -1,7 +1,4 @@
-using System;
-using System.Collections.Generic;
 using DataStructures.Hashing.NumberTheory;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.Hashing.NumberTheory;
 

DataStructures.Tests/Heap/BinaryHeapTests.cs

@@ -1,7 +1,4 @@
-using System;
-using System.Collections.Generic;
 using DataStructures.Heap;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.Heap;
 
@@ -52,7 +49,7 @@ public static void Pop_RemoveElements_HeapStillValid()
 
         Assert.That(heap.Pop(), Is.EqualTo(10));
         Assert.That(heap.Count, Is.EqualTo(9));
-        Assert.That(heap.Contains(10),Is.False);
+        Assert.That(heap.Contains(10), Is.False);
 
         Assert.That(heap.Pop(), Is.EqualTo(9));
         Assert.That(heap.Count, Is.EqualTo(8));

DataStructures.Tests/Heap/FibonacciHeaps/FibonacciHeapTests.cs

@@ -1,6 +1,4 @@
-using System;
 using DataStructures.Heap.FibonacciHeap;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.Heap.FibonacciHeaps;
 
@@ -41,7 +39,7 @@ public static void Push_AddElements_BuildCorrectHeap()
     {
         var heap = BuildTestHeap();
 
-        Assert.That(heap.Peek(),Is.EqualTo(1));
+        Assert.That(heap.Peek(), Is.EqualTo(1));
         Assert.That(heap.Count, Is.EqualTo(10));
     }
 

DataStructures.Tests/Heap/MinMaxHeapTests.cs

@@ -1,8 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using DataStructures.Heap;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.Heap;
 

DataStructures.Tests/Heap/PairingHeap/PairingHeapComparerTests.cs

@@ -1,7 +1,4 @@
-using System.Collections.Generic;
 using DataStructures.Heap.PairingHeap;
-using FluentAssertions;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.Heap.PairingHeap;
 

DataStructures.Tests/Heap/PairingHeap/PairingHeapTests.cs

@@ -1,9 +1,5 @@
-using System;
 using System.Collections;
-using System.Linq;
 using DataStructures.Heap.PairingHeap;
-using FluentAssertions;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.Heap.PairingHeap;
 

DataStructures.Tests/InvertedIndexTests.cs

@@ -1,7 +1,3 @@
-using System.Collections.Generic;
-using FluentAssertions;
-using NUnit.Framework;
-
 namespace DataStructures.Tests;
 
 public class InvertedIndexTests

DataStructures.Tests/LinkedList/CircularLinkedListTests.cs

@@ -1,6 +1,4 @@
-using System;
 using DataStructures.LinkedList.CircularLinkedList;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.LinkedList;
 
@@ -65,7 +63,7 @@ public static void TestInsertAfterInEmptyList()
         var cll = new CircularLinkedList<int>();
         var ex = Assert.Throws<InvalidOperationException>(() => cll.InsertAfter(10, 20));
 
-        Assert.That(ex!.Message, Is.EqualTo("List is empty."));       
+        Assert.That(ex!.Message, Is.EqualTo("List is empty."));
     }
 
     [Test]

DataStructures.Tests/LinkedList/DoublyLinkedListTests.cs

@@ -1,7 +1,4 @@
-using System;
-using System.Linq;
 using DataStructures.LinkedList.DoublyLinkedList;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.LinkedList;
 
@@ -65,7 +62,7 @@ public static void TestRemove()
         var arr = dll.GetData().ToArray();
         var reversedArr = dll.GetDataReversed().ToArray();
 
-        Assert.That(dll.Count, Is.EqualTo(2)    );
+        Assert.That(dll.Count, Is.EqualTo(2));
         Assert.That(new[] { 1, 3 }, Is.EqualTo(arr));
         Assert.That(new[] { 3, 1 }, Is.EqualTo(reversedArr));
     }

DataStructures.Tests/LinkedList/LinkedListTests.cs

@@ -1,7 +1,4 @@
-using System;
-using System.Linq;
 using DataStructures.LinkedList.SinglyLinkedList;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.LinkedList;
 

DataStructures.Tests/LinkedList/SkipListTests.cs

@@ -1,8 +1,4 @@
-using System;
 using DataStructures.LinkedList.SkipList;
-using NUnit.Framework;
-using FluentAssertions;
-using System.Collections.Generic;
 
 namespace DataStructures.Tests.LinkedList;
 
@@ -92,7 +88,7 @@ public static void TestRemove_ItemRemoved()
         isRemoved.Should().BeTrue();
     }
 
-     [Test]
+    [Test]
     public static void TestRemove_ItemNotFound()
     {
         var list = new SkipList<int>();

DataStructures.Tests/Probabilistic/BloomFilterTests.cs

@@ -1,9 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
 using DataStructures.Probabilistic;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.Probabilistic;
 

DataStructures.Tests/Probabilistic/CountMinSketchTests.cs

@@ -1,8 +1,4 @@
-using System;
-using System.Collections.Generic;
 using DataStructures.Probabilistic;
-using NUnit.Framework;
-using FluentAssertions;
 
 namespace DataStructures.Tests.Probabilistic;
 
@@ -61,7 +57,7 @@ public void TestProbabilities()
     {
         var sketch = new CountMinSketch<int>(.01, .05);
         var random = new Random();
-        var insertedItems = new Dictionary<int,int>();
+        var insertedItems = new Dictionary<int, int>();
         for (var i = 0; i < 10000; i++)
         {
             var item = random.Next(0, 1000000);

DataStructures.Tests/Probabilistic/HyperLogLogTest.cs

@@ -1,8 +1,4 @@
-using System;
-using System.Collections.Generic;
 using DataStructures.Probabilistic;
-using FluentAssertions;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.Probabilistic;
 
@@ -12,7 +8,7 @@ public class HyperLogLogTest
     public void TestHyperLogLog()
     {
         var hll = new HyperLogLog<int>();
-        HashSet<int> actual = new ();
+        HashSet<int> actual = new();
 
         var rand = new Random();
         var tolerance = .05;
@@ -36,7 +32,7 @@ public void TestHyperLogLogMerge()
         var hll2 = new HyperLogLog<int>();
         var rand = new Random();
         var tolerance = .05;
-        HashSet<int> actual = new ();
+        HashSet<int> actual = new();
         for (var i = 0; i < 5000; i++)
         {
             var k = rand.Next(20000);

DataStructures.Tests/Queue/ArrayBasedQueueTests.cs

@@ -1,7 +1,4 @@
-using System;
-using System.Text;
 using DataStructures.Queue;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.Queue;
 

DataStructures.Tests/Queue/ListBasedQueueTests.cs

@@ -1,7 +1,4 @@
-using System;
-using System.Text;
 using DataStructures.Queue;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.Queue;
 

DataStructures.Tests/Queue/StackBasedQueueTests.cs

@@ -1,7 +1,4 @@
-using System;
-using System.Text;
 using DataStructures.Queue;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.Queue;
 

DataStructures.Tests/RedBlackTreeTests.cs

@@ -1,9 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using DataStructures.RedBlackTree;
-using FluentAssertions;
-using NUnit.Framework;
 
 namespace DataStructures.Tests;
 

DataStructures.Tests/ScapegoatTree/ExtensionsTests.cs

@@ -1,7 +1,4 @@
-using System;
-using System.Collections.Generic;
 using DataStructures.ScapegoatTree;
-using NUnit.Framework;
 
 namespace DataStructures.Tests.ScapegoatTree;