diff --git a/src/Tests/UnitTestsModel/ActivityTest.cs b/src/Tests/UnitTestsModel/ActivityTest.cs
index 94be218..df8e2dd 100644
--- a/src/Tests/UnitTestsModel/ActivityTest.cs
+++ b/src/Tests/UnitTestsModel/ActivityTest.cs
@@ -1,152 +1,166 @@
+//-----------------------------------------------------------------------
+// FILENAME: ActivityTests.cs
+// PROJECT: UnitTestsModel
+// DATE CREATED: 16/03/2024
+// AUTHOR: HeartTeam
+// PURPOSE: Contains unit tests for the Activity class in the Model namespace.
+//-----------------------------------------------------------------------
+
 using System;
 using System.Collections.Generic;
 using Model;
 using Xunit;
 
-namespace UnitTestsModel;
-public class ActivityTests
+namespace UnitTestsModel
 {
-    [Fact]
-    public void Constructor_WithValidEffort_SetsEffort()
+    /// <summary>
+    /// Contains unit tests for the <see cref="Activity"/> class.
+    /// </summary>
+    public class ActivityTests
     {
-        // Arrange
-        var date = DateTime.Now;
-        var validEffort = 3;
+        /// <summary>
+        /// Verifies that the constructor sets the effort property correctly when a valid effort is provided.
+        /// </summary>
+        [Fact]
+        public void Constructor_WithValidEffort_SetsEffort()
+        {
+            var date = DateTime.Now;
+            var validEffort = 3;
 
-        // Act
-        var activity = new Activity(
-            id: 1,
-            type: "Running",
-            date: date,
-            startTime: date.AddHours(1),
-            endTime: date.AddHours(2),
-            effort: validEffort,
-            variability: 0.5f,
-            variance: 0.3f,
-            standardDeviation: 0.2f,
-            average: 150,
-            maximum: 180,
-            minimum: 120,
-            averageTemperature: 25.5f,
-            hasAutoPause: false,
-            user: new User(),
-            dataSource: new DataSource(1, "Type", "Model", 0.1f, new List<User>(), new List<Activity>()),
-            heartRates: null
-        );
+            var activity = new Activity(
+                id: 1,
+                type: "Running",
+                date: date,
+                startTime: date.AddHours(1),
+                endTime: date.AddHours(2),
+                effort: validEffort,
+                variability: 0.5f,
+                variance: 0.3f,
+                standardDeviation: 0.2f,
+                average: 150,
+                maximum: 180,
+                minimum: 120,
+                averageTemperature: 25.5f,
+                hasAutoPause: false,
+                user: new User(),
+                dataSource: new DataSource(1, "Type", "Model", 0.1f, new List<User>(), new List<Activity>()),
+                heartRates: null
+            );
 
-        // Assert
-        Assert.Equal(validEffort, activity.Effort);
-    }
+            Assert.Equal(validEffort, activity.Effort);
+        }
 
-    [Fact]
-    public void Constructor_WithInvalidEffort_ThrowsArgumentException()
-    {
-        // Arrange
-        var date = DateTime.Now;
-        var invalidEffort = 6;
+        /// <summary>
+        /// Verifies that the constructor throws an ArgumentException when an invalid effort is provided.
+        /// </summary>
+        [Fact]
+        public void Constructor_WithInvalidEffort_ThrowsArgumentException()
+        {
+            var date = DateTime.Now;
+            var invalidEffort = 6;
 
-        // Act & Assert
-        Assert.Throws<ArgumentException>(() => new Activity(
-            id: 1,
-            type: "Running",
-            date: date,
-            startTime: date.AddHours(1),
-            endTime: date.AddHours(2),
-            effort: invalidEffort,
-            variability: 0.5f,
-            variance: 0.3f,
-            standardDeviation: 0.2f,
-            average: 150,
-            maximum: 180,
-            minimum: 120,
-            averageTemperature: 25.5f,
-            hasAutoPause: false,
-            user: new User(),
-            dataSource: new DataSource(1, "Type", "Model", 0.1f, new List<User>(), new List<Activity>()),
-            heartRates: null
-        ));
-    }
+            Assert.Throws<ArgumentException>(() => new Activity(
+                id: 1,
+                type: "Running",
+                date: date,
+                startTime: date.AddHours(1),
+                endTime: date.AddHours(2),
+                effort: invalidEffort,
+                variability: 0.5f,
+                variance: 0.3f,
+                standardDeviation: 0.2f,
+                average: 150,
+                maximum: 180,
+                minimum: 120,
+                averageTemperature: 25.5f,
+                hasAutoPause: false,
+                user: new User(),
+                dataSource: new DataSource(1, "Type", "Model", 0.1f, new List<User>(), new List<Activity>()),
+                heartRates: null
+            ));
+        }
 
-    [Fact]
-    public void ToString_ReturnsExpectedString()
-    {
-        // Arrange
-        var date = new DateTime(2023, 3, 16, 10, 0, 0);
-        var activity = new Activity(
-            id: 1,
-            type: "Running",
-            date: date,
-            startTime: date.AddHours(1),
-            endTime: date.AddHours(2),
-            effort: 3,
-            variability: 0.5f,
-            variance: 0.3f,
-            standardDeviation: 0.2f,
-            average: 150,
-            maximum: 180,
-            minimum: 120,
-            averageTemperature: 25.5f,
-            hasAutoPause: false,
-            user: new User(),
-            dataSource: new DataSource(1, "Type", "Model", 0.1f, new List<User>(), new List<Activity>()),
-            heartRates: null
-        );
+        /// <summary>
+        /// Verifies that the ToString method returns the expected string representation of the activity.
+        /// </summary>
+        [Fact]
+        public void ToString_ReturnsExpectedString()
+        {
+            var date = new DateTime(2023, 3, 16, 10, 0, 0);
+            var activity = new Activity(
+                id: 1,
+                type: "Running",
+                date: date,
+                startTime: date.AddHours(1),
+                endTime: date.AddHours(2),
+                effort: 3,
+                variability: 0.5f,
+                variance: 0.3f,
+                standardDeviation: 0.2f,
+                average: 150,
+                maximum: 180,
+                minimum: 120,
+                averageTemperature: 25.5f,
+                hasAutoPause: false,
+                user: new User(),
+                dataSource: new DataSource(1, "Type", "Model", 0.1f, new List<User>(), new List<Activity>()),
+                heartRates: null
+            );
 
-        // Act
-        var result = activity.ToString();
+            var result = activity.ToString();
 
-        // Assert
-        Assert.Contains("Activity #1: Running on 16/3/2023 from 11:00:00 to 12:00:00", result);
-    }
+            Assert.Contains("Activity #1: Running on 16/3/2023 from 11:00:00 to 12:00:00", result);
+        }
 
-    [Fact]
-    public void Constructor_SetsPropertiesCorrectly()
-    {
-        // Arrange
-        var date = DateTime.Now;
-        var user = new User();
-        var dataSource = new DataSource(1, "Type", "Model", 0.1f, new List<User>(), new List<Activity>());
-        var heartRates = new List<HeartRate>();
+        /// <summary>
+        /// Verifies that the constructor sets all properties correctly.
+        /// </summary>
+        [Fact]
+        public void Constructor_SetsPropertiesCorrectly()
+        {
+            var date = DateTime.Now;
+            var user = new User();
+            var dataSource = new DataSource(1, "Type", "Model", 0.1f, new List<User>(), new List<Activity>());
+            var heartRates = new List<HeartRate>();
 
-        // Act
-        var activity = new Activity(
-            id: 1,
-            type: "Running",
-            date: date,
-            startTime: date.AddHours(1),
-            endTime: date.AddHours(2),
-            effort: 3,
-            variability: 0.5f,
-            variance: 0.3f,
-            standardDeviation: 0.2f,
-            average: 150,
-            maximum: 180,
-            minimum: 120,
-            averageTemperature: 25.5f,
-            hasAutoPause: false,
-            user: user,
-            dataSource: dataSource,
-            heartRates: heartRates
-        );
+            var activity = new Activity(
+                id: 1,
+                type: "Running",
+                date: date,
+                startTime: date.AddHours(1),
+                endTime: date.AddHours(2),
+                effort: 3,
+                variability: 0.5f,
+                variance: 0.3f,
+                standardDeviation: 0.2f,
+                average: 150,
+                maximum: 180,
+                minimum: 120,
+                averageTemperature: 25.5f,
+                hasAutoPause: false,
+                user: user,
+                dataSource: dataSource,
+                heartRates: heartRates
+            );
 
-        // Assert
-        Assert.Equal(1, activity.Id);
-        Assert.Equal("Running", activity.Type);
-        Assert.Equal(date, activity.Date);
-        Assert.Equal(date.AddHours(1), activity.StartTime);
-        Assert.Equal(date.AddHours(2), activity.EndTime);
-        Assert.Equal(3, activity.Effort);
-        Assert.Equal(0.5f, activity.Variability);
-        Assert.Equal(0.3f, activity.Variance);
-        Assert.Equal(0.2f, activity.StandardDeviation);
-        Assert.Equal(150, activity.Average);
-        Assert.Equal(180, activity.Maximum);
-        Assert.Equal(120, activity.Minimum);
-        Assert.Equal(25.5f, activity.AverageTemperature);
-        Assert.False(activity.HasAutoPause);
-        Assert.Equal(user, activity.Athlete);
-        Assert.Equal(dataSource, activity.DataSource);
-        Assert.Equal(heartRates, activity.HeartRates);
-    }
+            Assert.Equal(1, activity.Id);
+            Assert.Equal("Running", activity.Type);
+            Assert.Equal(date, activity.Date);
+            Assert.Equal(date.AddHours(1), activity.StartTime);
+            Assert.Equal(date.AddHours(2), activity.EndTime);
+            Assert.Equal(3, activity.Effort);
+            Assert.Equal(0.5f, activity.Variability);
+            Assert.Equal(0.3f, activity.Variance);
+            Assert.Equal(0.2f, activity.StandardDeviation);
+            Assert.Equal(150, activity.Average);
+            Assert.Equal(180, activity.Maximum);
+            Assert.Equal(120, activity.Minimum);
+            Assert.Equal(25.5f, activity.AverageTemperature);
+            Assert.False(activity.HasAutoPause);
+            Assert.Equal(user, activity.Athlete);
+            Assert.Equal(dataSource, activity.DataSource);
+            Assert.Equal(heartRates, activity.HeartRates);
+        }
 
-}
+    }
+}
\ No newline at end of file
diff --git a/src/Tests/UnitTestsModel/AthleteTest.cs b/src/Tests/UnitTestsModel/AthleteTest.cs
new file mode 100644
index 0000000..4b90322
--- /dev/null
+++ b/src/Tests/UnitTestsModel/AthleteTest.cs
@@ -0,0 +1,49 @@
+using Model;
+using Xunit;
+
+namespace Model.Tests
+{
+    public class AthleteTests
+    {
+        [Fact]
+        public void CheckAdd_ValidUser_ReturnsTrue()
+        {
+            // Arrange
+            var athlete = new Athlete();
+
+            // Act
+            var user = new User();
+            var result = athlete.CheckAdd(user);
+
+            // Assert
+            Assert.True(result);
+        }
+
+        [Fact]
+        public void CheckAdd_NullUser_ReturnsFalse()
+        {
+            // Arrange
+            var athlete = new Athlete();
+
+            // Act
+            var result = athlete.CheckAdd(null);
+
+            // Assert
+            Assert.False(result);
+        }
+
+        [Fact]
+        public void CheckAdd_NonAthleteUser_ReturnsFalse()
+        {
+            // Arrange
+            var athlete = new Athlete();
+
+            // Act
+            var user = new User { Role = new Coach() }; // Assuming Coach inherits from Role
+            var result = athlete.CheckAdd(user);
+
+            // Assert
+            Assert.False(result);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Tests/UnitTestsModel/CoachTest.cs b/src/Tests/UnitTestsModel/CoachTest.cs
new file mode 100644
index 0000000..c54f4c4
--- /dev/null
+++ b/src/Tests/UnitTestsModel/CoachTest.cs
@@ -0,0 +1,49 @@
+using Model;
+using Xunit;
+
+namespace Model.Tests
+{
+    public class CoachTests
+    {
+        [Fact]
+        public void CheckAdd_AthleteUser_ReturnsTrue()
+        {
+            // Arrange
+            var coach = new Coach();
+
+            // Act
+            var user = new User { Role = new Athlete() };
+            var result = coach.CheckAdd(user);
+
+            // Assert
+            Assert.True(result);
+        }
+
+        [Fact]
+        public void CheckAdd_NonAthleteUser_ReturnsFalse()
+        {
+            // Arrange
+            var coach = new Coach();
+
+            // Act
+            var user = new User { Role = new Coach() };
+            var result = coach.CheckAdd(user);
+
+            // Assert
+            Assert.False(result);
+        }
+
+        [Fact]
+        public void CheckAdd_NullUser_ReturnsFalse()
+        {
+            // Arrange
+            var coach = new Coach();
+
+            // Act
+            var result = coach.CheckAdd(null);
+
+            // Assert
+            Assert.False(result);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Tests/UnitTestsModel/DataSource.cs b/src/Tests/UnitTestsModel/DataSource.cs
new file mode 100644
index 0000000..21cad2d
--- /dev/null
+++ b/src/Tests/UnitTestsModel/DataSource.cs
@@ -0,0 +1,32 @@
+using Model;
+using System.Collections.Generic;
+using Xunit;
+
+namespace Model.Tests
+{
+    public class DataSourceTests
+    {
+        [Fact]
+        public void Constructor_WithArguments_InitializesProperties()
+        {
+            // Arrange
+            var id = 1;
+            var type = "Type";
+            var model = "Model";
+            var precision = 0.5f;
+            var athletes = new List<User>();
+            var activities = new List<Activity>();
+
+            // Act
+            var dataSource = new DataSource(id, type, model, precision, athletes, activities);
+
+            // Assert
+            Assert.Equal(id, dataSource.Id);
+            Assert.Equal(type, dataSource.Type);
+            Assert.Equal(model, dataSource.Model);
+            Assert.Equal(precision, dataSource.Precision);
+            Assert.Same(athletes, dataSource.Athletes);
+            Assert.Same(activities, dataSource.Activities);
+        }
+    }
+}
diff --git a/src/Tests/UnitTestsModel/GlobalUsings.cs b/src/Tests/UnitTestsModel/GlobalUsings.cs
deleted file mode 100644
index 8c927eb..0000000
--- a/src/Tests/UnitTestsModel/GlobalUsings.cs
+++ /dev/null
@@ -1 +0,0 @@
-global using Xunit;
\ No newline at end of file
diff --git a/src/Tests/UnitTestsModel/HeartRateTest.cs b/src/Tests/UnitTestsModel/HeartRateTest.cs
new file mode 100644
index 0000000..bfdcae7
--- /dev/null
+++ b/src/Tests/UnitTestsModel/HeartRateTest.cs
@@ -0,0 +1,73 @@
+using Xunit;
+using System;
+
+namespace Model.Tests
+{
+    public class HeartRateTests
+    {
+        [Fact]
+        public void HeartRate_Constructor_WithValidParameters()
+        {
+            // Arrange
+            int id = 1;
+            int bpm = 80;
+            TimeOnly timestamp = new TimeOnly(12, 30, 0);
+            Activity activity = new Activity();
+            double? latitude = 40.7128;
+            double? longitude = -74.0060;
+            double? altitude = 10.5;
+            int? cadence = 120;
+            double? distance = 5.2;
+            double? speed = 10.5;
+            int? power = 200;
+            double? temperature = 25.5;
+
+            // Act
+            var heartRate = new HeartRate(id, bpm, timestamp, activity, latitude, longitude, altitude, cadence, distance, speed, power, temperature);
+
+            // Assert
+            Assert.Equal(id, heartRate.Id);
+            Assert.Equal(bpm, heartRate.Bpm);
+            Assert.Equal(timestamp, heartRate.Timestamp);
+            Assert.Equal(activity, heartRate.Activity);
+            Assert.Equal(latitude, heartRate.Latitude);
+            Assert.Equal(longitude, heartRate.Longitude);
+            Assert.Equal(altitude, heartRate.Altitude);
+            Assert.Equal(cadence, heartRate.Cadence);
+            Assert.Equal(distance, heartRate.Distance);
+            Assert.Equal(speed, heartRate.Speed);
+            Assert.Equal(power, heartRate.Power);
+            Assert.Equal(temperature, heartRate.Temperature);
+        }
+
+        [Fact]
+        public void HeartRate_ToString_ReturnsExpectedString()
+        {
+            // Arrange
+            int id = 1;
+            int bpm = 80;
+            TimeOnly timestamp = new TimeOnly(12, 30, 0);
+            Activity activity = new Activity();
+            double? latitude = 40.7128;
+            double? longitude = -74.0060;
+            double? altitude = 10.5;
+            int? cadence = 120;
+            double? distance = 5.2;
+            double? speed = 10.5;
+            int? power = 200;
+            double? temperature = 25.5;
+            var heartRate = new HeartRate(id, bpm, timestamp, activity, latitude, longitude, altitude, cadence, distance, speed, power, temperature);
+
+            // Act
+            var result = heartRate.ToString();
+
+            // Assert
+            Assert.Contains($"HeartRate #{id}", result);
+            Assert.Contains($"{bpm} bpm", result);
+            Assert.Contains($"{timestamp:HH:mm:ss}", result);
+            Assert.Contains($"temperature of {temperature}°C", result);
+            Assert.Contains($"altitude of {altitude}m", result);
+            Assert.Contains($"at {longitude}°E and {latitude}°N", result);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Tests/UnitTestsModel/LargeImageTest.cs b/src/Tests/UnitTestsModel/LargeImageTest.cs
new file mode 100644
index 0000000..d1f5552
--- /dev/null
+++ b/src/Tests/UnitTestsModel/LargeImageTest.cs
@@ -0,0 +1,38 @@
+using Xunit;
+
+namespace Model.Tests
+{
+    public class LargeImageTests
+    {
+        [Fact]
+        public void Equals_ReturnsTrue_WhenBase64StringsAreEqual()
+        {
+            // Arrange
+            var base64String = "VGhpcyBpcyBhIGJhc2U2NCBlbmNvZGVkIHN0cmluZw==";
+            var image1 = new LargeImage(base64String);
+            var image2 = new LargeImage(base64String);
+
+            // Act
+            var result = image1.Equals(image2);
+
+            // Assert
+            Assert.True(result);
+        }
+
+        [Fact]
+        public void Equals_ReturnsFalse_WhenBase64StringsAreDifferent()
+        {
+            // Arrange
+            var base64String1 = "VGhpcyBpcyBhIGJhc2U2NCBlbmNvZGVkIHN0cmluZw==";
+            var base64String2 = "VGhpcyBpcyBhIGJhc2U2NSBlbmNvZGVkIHN0cmluZw==";
+            var image1 = new LargeImage(base64String1);
+            var image2 = new LargeImage(base64String2);
+
+            // Act
+            var result = image1.Equals(image2);
+
+            // Assert
+            Assert.False(result);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Tests/UnitTestsModel/NotificationTest.cs b/src/Tests/UnitTestsModel/NotificationTest.cs
new file mode 100644
index 0000000..fc9fbd1
--- /dev/null
+++ b/src/Tests/UnitTestsModel/NotificationTest.cs
@@ -0,0 +1,30 @@
+using Xunit;
+
+namespace Model.Tests
+{
+    public class NotificationTests
+    {
+        [Fact]
+        public void Constructor_InitializesPropertiesCorrectly()
+        {
+            // Arrange
+            int id = 1;
+            string message = "Test notification";
+            DateTime date = DateTime.Now;
+            bool status = false;
+            string urgency = "High";
+            int toUserId = 10;
+
+            // Act
+            var notification = new Notification(id, message, date, status, urgency, toUserId);
+
+            // Assert
+            Assert.Equal(id, notification.IdNotif);
+            Assert.Equal(message, notification.Message);
+            Assert.Equal(date, notification.Date);
+            Assert.Equal(status, notification.Statut);
+            Assert.Equal(urgency, notification.Urgence);
+            Assert.Equal(toUserId, notification.ToUserId);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Tests/UnitTestsModel/RelationshipTest.cs b/src/Tests/UnitTestsModel/RelationshipTest.cs
new file mode 100644
index 0000000..b55d08c
--- /dev/null
+++ b/src/Tests/UnitTestsModel/RelationshipTest.cs
@@ -0,0 +1,31 @@
+using Xunit;
+
+namespace Model.Tests
+{
+    public class RelationshipRequestTests
+    {
+        [Fact]
+        public void Constructor_InitializesPropertiesCorrectly()
+        {
+            // Arrange
+            int id = 1;
+            int fromUserId = 2;
+            int toUserId = 3;
+            string status = "Pending";
+
+            // Act
+            var request = new RelationshipRequest
+            {
+                Id = id,
+                FromUser = fromUserId,
+                ToUser = toUserId
+            };
+
+            // Assert
+            Assert.Equal(id, request.Id);
+            Assert.Equal(fromUserId, request.FromUser);
+            Assert.Equal(toUserId, request.ToUser);
+            Assert.Equal(status, request.Status);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Tests/UnitTestsModel/RoleTest.cs b/src/Tests/UnitTestsModel/RoleTest.cs
new file mode 100644
index 0000000..aa9c0a5
--- /dev/null
+++ b/src/Tests/UnitTestsModel/RoleTest.cs
@@ -0,0 +1,36 @@
+using Xunit;
+
+namespace Model.Tests
+{
+    public class RoleTests
+    {
+        [Fact]
+        public void AddUser_WithValidUser_ReturnsTrue()
+        {
+            // Arrange
+            var role = new Athlete(); // Vous pouvez utiliser Athlete ou Coach selon votre besoin
+            var user = new User(); // Créez un objet User valide
+
+            // Act
+            bool result = role.AddUser(user);
+
+            // Assert
+            Assert.True(result);
+        }
+
+        [Fact]
+        public void AddUser_WithInvalidUser_ReturnsFalse()
+        {
+            // Arrange
+            var role = new Athlete(); // Vous pouvez utiliser Athlete ou Coach selon votre besoin
+            var user = new User(); // Créez un objet User invalide
+
+            // Act
+            bool result = role.AddUser(user);
+
+            // Assert
+            Assert.False(result);
+        }
+
+    }
+}
diff --git a/src/Tests/UnitTestsModel/UnitTest1.cs b/src/Tests/UnitTestsModel/UnitTest1.cs
deleted file mode 100644
index 0018230..0000000
--- a/src/Tests/UnitTestsModel/UnitTest1.cs
+++ /dev/null
@@ -1,10 +0,0 @@
-namespace UnitTestsModel;
-
-public class UnitTest1
-{
-    [Fact]
-    public void Test1()
-    {
-
-    }
-}
\ No newline at end of file
diff --git a/src/Tests/UnitTestsModel/UserTest.cs b/src/Tests/UnitTestsModel/UserTest.cs
new file mode 100644
index 0000000..efd95a8
--- /dev/null
+++ b/src/Tests/UnitTestsModel/UserTest.cs
@@ -0,0 +1,41 @@
+using Xunit;
+
+namespace Model.Tests
+{
+    public class UserTests
+    {
+        [Fact]
+        public void UserConstructor_ValidParameters_ConstructsObject()
+        {
+            // Arrange
+            string username = "john_doe";
+            string profilePicture = "profile.jpg";
+            string lastName = "Doe";
+            string firstName = "John";
+            string email = "john.doe@example.com";
+            string password = "password";
+            string sex = "Male";
+            float length = 180.5f;
+            float weight = 75.3f;
+            DateTime dateOfBirth = new DateTime(1990, 5, 15);
+            Role role = new Athlete(); // You can change this to the appropriate role
+
+            // Act
+            User user = new User(username, profilePicture, lastName, firstName, email, password, sex, length, weight, dateOfBirth, role);
+
+            // Assert
+            Assert.NotNull(user);
+            Assert.Equal(username, user.Username);
+            Assert.Equal(profilePicture, user.ProfilePicture);
+            Assert.Equal(lastName, user.LastName);
+            Assert.Equal(firstName, user.FirstName);
+            Assert.Equal(email, user.Email);
+            Assert.Equal(password, user.MotDePasse);
+            Assert.Equal(sex, user.Sexe);
+            Assert.Equal(length, user.Lenght);
+            Assert.Equal(weight, user.Weight);
+            Assert.Equal(dateOfBirth, user.DateOfBirth);
+            Assert.Equal(role, user.Role);
+        }
+    }
+}
\ No newline at end of file