diff --git a/MCTG/MCTGApp/Program.cs b/MCTG/MCTGApp/Program.cs
index 9998a9b..9196a9a 100644
--- a/MCTG/MCTGApp/Program.cs
+++ b/MCTG/MCTGApp/Program.cs
@@ -1,6 +1,6 @@
 // See https://aka.ms/new-console-template for more information
 
-using Model;
+using MCTGLib;
 
 
 Console.WriteLine("Hello, World!\n");
diff --git a/MCTG/MCTGLib/BaseItem.cs b/MCTG/MCTGLib/BaseItem.cs
index 8d8cd81..9d60520 100644
--- a/MCTG/MCTGLib/BaseItem.cs
+++ b/MCTG/MCTGLib/BaseItem.cs
@@ -3,7 +3,7 @@ using System;
 using System.ComponentModel;
 using System.Diagnostics.CodeAnalysis;
 
-namespace Model
+namespace MCTGLib
 {
     /// <summary>
     /// Define the base structure of any Items.<br/>
diff --git a/MCTG/MCTGLib/IDisplayable.cs b/MCTG/MCTGLib/IDisplayable.cs
index fed294c..5de9319 100644
--- a/MCTG/MCTGLib/IDisplayable.cs
+++ b/MCTG/MCTGLib/IDisplayable.cs
@@ -1,4 +1,4 @@
-namespace Model
+namespace MCTGLib
 {
     /// <summary>
     /// Define an Item that can be displayed.
diff --git a/MCTG/MCTGLib/Recipe.cs b/MCTG/MCTGLib/Recipe.cs
index f5cb00d..7e55030 100644
--- a/MCTG/MCTGLib/Recipe.cs
+++ b/MCTG/MCTGLib/Recipe.cs
@@ -1,7 +1,7 @@
 using System;
 using System.Collections.Generic;
 
-namespace Model
+namespace MCTGLib
 {
     /// <summary>
     /// A Recipe is a description of step and maybe some techniques, with an ingredient list to make a meal.<br/>
diff --git a/MCTG/MCTGLib/RecipeCollection.cs b/MCTG/MCTGLib/RecipeCollection.cs
index 0611a0f..4e799d3 100644
--- a/MCTG/MCTGLib/RecipeCollection.cs
+++ b/MCTG/MCTGLib/RecipeCollection.cs
@@ -3,7 +3,7 @@ using System.Collections;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 
-namespace Model
+namespace MCTGLib
 {
     /// <summary>
     /// A Recipe collection is a group of recipe.<br/>
@@ -15,7 +15,7 @@ namespace Model
 
         private const int CAT_ITEM = 2;                             // the first number of the item full id : the item category.
         private static uint _idCreator = 0;                         // stand for the creation of a new id. It is incremented each time a new Recipe is instantiated.
-        private ICollection<Recipe> _recipes = new List<Recipe>();  // main composent of this class.
+        private readonly ICollection<Recipe> _recipes = new List<Recipe>();  // main composent of this class.
 
         #endregion
 
diff --git a/MCTG/Tests/MCTGLib_UnitTests/MCTGLib_UnitTests.csproj b/MCTG/Tests/MCTGLib_UnitTests/MCTGLib_UnitTests.csproj
index 42ff44d..afc37b6 100644
--- a/MCTG/Tests/MCTGLib_UnitTests/MCTGLib_UnitTests.csproj
+++ b/MCTG/Tests/MCTGLib_UnitTests/MCTGLib_UnitTests.csproj
@@ -22,4 +22,8 @@
     </PackageReference>
   </ItemGroup>
 
+  <ItemGroup>
+    <ProjectReference Include="..\..\MCTGLib\MCTGLib.csproj" />
+  </ItemGroup>
+
 </Project>
diff --git a/MCTG/Tests/MCTGLib_UnitTests/Recipe_UT.cs b/MCTG/Tests/MCTGLib_UnitTests/Recipe_UT.cs
new file mode 100644
index 0000000..3196733
--- /dev/null
+++ b/MCTG/Tests/MCTGLib_UnitTests/Recipe_UT.cs
@@ -0,0 +1,34 @@
+using MCTGLib;
+
+namespace MCTGLib_UnitTests
+{
+    public class Recipe_UT
+    {
+        [Fact]
+        public void TestConstructorNotNull()
+        {
+            Recipe r1 = new Recipe();
+            Assert.NotNull(r1);
+        }
+
+        [Fact]
+        public void TestConstructorWithValidDefaults()
+        {
+            Recipe r1 = new Recipe();
+            Assert.Equal("Recipe n10", r1.Title);
+            Assert.Equal("A recipe.", r1.Description);
+        }
+
+        [Fact]
+        public void TestComputeId()
+        {
+            List<Recipe> lr = new List<Recipe>();
+            for (int i = 0; i < 11; i++)
+                lr.Add(new Recipe());
+
+            Assert.Equal((uint)18, lr.ElementAt(8).Id);
+            Assert.Equal((uint)19, lr.ElementAt(9).Id);
+            Assert.Equal((uint)110, lr.ElementAt(10).Id);
+        }
+    }
+}
\ No newline at end of file
diff --git a/MCTG/Tests/MCTGLib_UnitTests/UnitTest1.cs b/MCTG/Tests/MCTGLib_UnitTests/UnitTest1.cs
deleted file mode 100644
index 4d22b68..0000000
--- a/MCTG/Tests/MCTGLib_UnitTests/UnitTest1.cs
+++ /dev/null
@@ -1,11 +0,0 @@
-namespace MCTGLib_UnitTests
-{
-    public class UnitTest1
-    {
-        [Fact]
-        public void Test1()
-        {
-
-        }
-    }
-}
\ No newline at end of file