diff --git a/MCTG/ConsoleApp/Menu/Entry.EntryStep.cs b/MCTG/ConsoleApp/Menu/Entry.EntryStep.cs
index ee9bdfb..b58a707 100644
--- a/MCTG/ConsoleApp/Menu/Entry.EntryStep.cs
+++ b/MCTG/ConsoleApp/Menu/Entry.EntryStep.cs
@@ -14,7 +14,7 @@ namespace ConsoleApp.Menu
         public class EntryStep
         {
             #region Attributes & Properties
-            private Type _entryType;
+            private readonly Type _entryType;
 
             /// <summary>
             /// The entry description. This text is generally placed before the input field.
diff --git a/MCTG/ConsoleApp/Menu/Entry.cs b/MCTG/ConsoleApp/Menu/Entry.cs
index cb08dbb..6c63792 100644
--- a/MCTG/ConsoleApp/Menu/Entry.cs
+++ b/MCTG/ConsoleApp/Menu/Entry.cs
@@ -13,7 +13,7 @@ namespace ConsoleApp.Menu
     internal abstract partial class Entry : Menu<Entry.EntryStep>
     {
         #region Attributes & Properties
-        private List<EntryStep> _steps = new List<EntryStep>();
+        private List<EntryStep> _steps;
         #endregion
 
         #region Constructors
@@ -56,7 +56,7 @@ namespace ConsoleApp.Menu
                 if (cki.Key == ConsoleKey.Escape)
                 {
                     if (CurrentSelected is null)
-                        throw new Exception("Error: CurrentSelected is null.");
+                        throw new ArgumentNullException("Error: CurrentSelected is null.");
 
                     CurrentSelected.Input = InputStr.ToString();
                     DisableWriteMode();
@@ -76,7 +76,7 @@ namespace ConsoleApp.Menu
 
         public override void Update()
         {
-            if (_selectList == null || _selectList.Count == 0)
+            if (_selectList.Count == 0)
             {
                 CurrentSelected = default;
                 return;
@@ -102,12 +102,12 @@ namespace ConsoleApp.Menu
                 _screenDisplay.Append($"{_selectList[i].Line} {_selectList[i].Item.Input}");
 
                 if (CurrentLine == i && WriteMode)
-                    _screenDisplay.Append(InputStr.ToString());
+                    _screenDisplay.Append(InputStr);
 
                 _screenDisplay.AppendLine();
             }
 
-            if (_selectList == null || _selectList.Count == 0)
+            if (_selectList.Count == 0)
                 _screenDisplay.AppendLine("Empty...");
 
             _screenDisplay.AppendLine(
diff --git a/MCTG/ConsoleApp/Menu/Menu.cs b/MCTG/ConsoleApp/Menu/Menu.cs
index 5f59e16..d556397 100644
--- a/MCTG/ConsoleApp/Menu/Menu.cs
+++ b/MCTG/ConsoleApp/Menu/Menu.cs
@@ -96,7 +96,7 @@ namespace ConsoleApp.Menu
         public virtual IMenu? Return()
         {
             if (CurrentSelected is null)
-                throw new Exception("Error: CurrentSelected is null.");
+                throw new ArgumentNullException("Error: CurrentSelected is null.");
 
             return (IMenu)CurrentSelected;
         }
@@ -104,7 +104,7 @@ namespace ConsoleApp.Menu
         protected virtual List<Selector<T>> SearchInSelection()
         {
             if (_allSelectors is null)
-                throw new Exception("Error: _allSelector is null.");
+                throw new ArgumentNullException("Error: _allSelector is null.");
 
             return _allSelectors.FindAll(x =>
                 x.Line.ToLower().Contains(InputStr.ToString().ToLower()));
@@ -141,7 +141,7 @@ namespace ConsoleApp.Menu
         {
             _selectList = SearchInSelection();
 
-            if (_selectList == null || _selectList.Count == 0)
+            if (_selectList.Count == 0)
             {
                 CurrentSelected = default;
                 return;
@@ -173,7 +173,7 @@ namespace ConsoleApp.Menu
                 _screenDisplay.AppendLine($"{_selectList[i].Line}");
             }
 
-            if (_selectList == null || _selectList.Count == 0)
+            if (_selectList.Count == 0)
                 _screenDisplay.AppendLine("Empty...");
 
             _screenDisplay.AppendLine(
diff --git a/MCTG/ConsoleApp/Menu/PlainText.cs b/MCTG/ConsoleApp/Menu/PlainText.cs
index f18379e..5ad4fa9 100644
--- a/MCTG/ConsoleApp/Menu/PlainText.cs
+++ b/MCTG/ConsoleApp/Menu/PlainText.cs
@@ -34,13 +34,13 @@ namespace ConsoleApp.Menu
 
         public bool WriteMode { get; set; }
         public StringBuilder InputStr { get; set; }
-        public void DisableWriteMode() { return; }
-        public void EnableWriteMode() { return; }
-        public void SelectNext() { return; }
-        public void SelectPrevious() { return; }
-        public void ToggleWriteMode() { return; }
-        public void Update() { return; }
-        public void WriteMenuMode(ConsoleKeyInfo cki) { return; }
+        public void DisableWriteMode() { }
+        public void EnableWriteMode() { }
+        public void SelectNext() { }
+        public void SelectPrevious() { }
+        public void ToggleWriteMode() { }
+        public void Update() { }
+        public void WriteMenuMode(ConsoleKeyInfo cki) { }
         #endregion
     }
 }
diff --git a/MCTG/ConsoleApp/Menu/SearcherRecipe.cs b/MCTG/ConsoleApp/Menu/SearcherRecipe.cs
index a04a041..af362f9 100644
--- a/MCTG/ConsoleApp/Menu/SearcherRecipe.cs
+++ b/MCTG/ConsoleApp/Menu/SearcherRecipe.cs
@@ -14,7 +14,7 @@ namespace ConsoleApp.Menu
     /// </summary>
     internal class SearcherRecipe : Menu<Recipe>
     {
-        private RecipeCollection _recipeCollectionOnSearch;
+        private readonly RecipeCollection _recipeCollectionOnSearch;
 
         public SearcherRecipe(RecipeCollection recipeCollection) : base("Search recipe")
         {
@@ -37,7 +37,7 @@ namespace ConsoleApp.Menu
         public override IMenu? Return()
         {
             if (CurrentSelected == null)
-                throw new Exception("Error: CurrentSelected is null.");
+                throw new ArgumentNullException("Error: CurrentSelected is null.");
 
             return new PlainText(CurrentSelected.ToString());
         }
diff --git a/MCTG/ConsoleApp/Program.cs b/MCTG/ConsoleApp/Program.cs
index d6aedee..eb526f6 100644
--- a/MCTG/ConsoleApp/Program.cs
+++ b/MCTG/ConsoleApp/Program.cs
@@ -13,7 +13,6 @@ Console.WriteLine("Hello, World!\n\n");
 
 Stub stub = new Stub();
 
-List<Recipe> recipes = stub.LoadRecipes();
 List<RecipeCollection> recipeCollections = stub.LoadRecipeCollection();
 
 RecipeCollection? allRecipe = recipeCollections.Find(x => x.Description.Equals("All"));
diff --git a/MCTG/ConsoleApp/Stubs/Stub.cs b/MCTG/ConsoleApp/Stubs/Stub.cs
index f116321..6824430 100644
--- a/MCTG/ConsoleApp/Stubs/Stub.cs
+++ b/MCTG/ConsoleApp/Stubs/Stub.cs
@@ -10,7 +10,7 @@ namespace ConsoleApp
 {
     internal struct Stub
     {
-        public List<Recipe> LoadRecipes()
+        public static List<Recipe> LoadRecipes()
         {
             List<Recipe> stub = new List<Recipe>();
             stub.AddRange(new[]
@@ -81,7 +81,7 @@ namespace ConsoleApp
         }
 
 
-        public List<User> ConstrucList()
+        public static List<User> ConstrucList()
         {
             List<User> Users = new List<User>();
 
diff --git a/MCTG/Tests/Model_UnitTests/RecipeCollection_UT.cs b/MCTG/Tests/Model_UnitTests/RecipeCollection_UT.cs
index 36008b1..3f09b70 100644
--- a/MCTG/Tests/Model_UnitTests/RecipeCollection_UT.cs
+++ b/MCTG/Tests/Model_UnitTests/RecipeCollection_UT.cs
@@ -22,7 +22,10 @@ namespace Model_UnitTests
                     new Recipe(title: "Gateau aux cerises", id: 3)
                 });
 
-            Assert.Equal(2, recipes.ResearchByName("chocolat").FirstOrDefault().Id);
+            Recipe? recipe = recipes.ResearchByName("chocolat").FirstOrDefault();
+
+            Assert.NotNull(recipe);
+            Assert.Equal(2, recipe.Id);
         }
     }
 }
diff --git a/MCTG/Tests/Model_UnitTests/test_unit_user.cs b/MCTG/Tests/Model_UnitTests/test_unit_user.cs
index 943afa0..1756e20 100644
--- a/MCTG/Tests/Model_UnitTests/test_unit_user.cs
+++ b/MCTG/Tests/Model_UnitTests/test_unit_user.cs
@@ -12,8 +12,8 @@ namespace Model_UnitTests
         [Fact]
         public void TestConstructUser()
         {
-            User user = new User("Bob","Dylan", "bd@gmail.com");
-            //Assert.
+            User? user = new User("Bob","Dylan", "bd@gmail.com");
+            Assert.NotNull(user);
         }
     }
 }