diff --git a/test/Application.UnitTests/Services/DomainService/IdentityServiceTests.cs b/test/Application.UnitTests/Services/DomainService/IdentityServiceTests.cs
new file mode 100644
index 0000000..20fc129
--- /dev/null
+++ b/test/Application.UnitTests/Services/DomainService/IdentityServiceTests.cs
@@ -0,0 +1,352 @@
+using Application.DTOs.Identity.ChangeRole;
+using Application.DTOs.Identity.CreateUser;
+using Application.DTOs.Identity.GetUser;
+using Application.DTOs.Identity.LoginUser;
+using Application.Interfaces;
+using Application.Interfaces.Repositories;
+using Application.Mappers;
+using Application.Services.DomainService;
+using Domain.Entities;
+using Microsoft.AspNetCore.Identity;
+using NSubstitute;
+using Web.DTOs.Identity;
+using Web.Mappers;
+
+namespace test.Application.UnitTests.Services.DomainService;
+
+public class IdentityServiceTests
+{
+    private readonly IUserManagerRepository _userManagerRepository;
+    private readonly IRoleManagerRepository _roleManagerRepository;
+    private readonly IJwtGenerator _jwtGenerator;
+    private readonly IdentityService _identityService;
+
+    public IdentityServiceTests()
+    {
+        _userManagerRepository = Substitute.For<IUserManagerRepository>();
+        _roleManagerRepository = Substitute.For<IRoleManagerRepository>();
+        _jwtGenerator = Substitute.For<IJwtGenerator>();
+        _identityService = new IdentityService(_userManagerRepository, _roleManagerRepository, _jwtGenerator);
+    }
+
+    // Signup Tests
+    [Fact]
+    public async Task SignUpUser_WhenRoleDoesNotExist_ReturnsFailResult()
+    {
+        // Arrange
+        var createUserRequest = new CreateUserRequest
+        {
+            UserName = "MobinBarfi",
+            Password = "Abc@123",
+            Email = "mobinbr99@gmail.com",
+            Role = "NonExistentRole"
+        };
+
+        _roleManagerRepository.RoleExistsAsync(createUserRequest.Role).Returns(Task.FromResult(false));
+
+        // Act
+        var result = await _identityService.SignUpUser(createUserRequest);
+
+        // Assert
+        Assert.False(result.Succeed);
+        Assert.Equal("role does not exist", result.Message);
+    }
+    
+    [Fact]
+    public async Task SignUpUser_WhenUserCreationFails_ReturnsFailResult()
+    {
+        // Arrange
+        var createUserRequest = new CreateUserRequest
+        {
+            UserName = "MobinBarfi",
+            Password = "Abc@123",
+            Email = "mobinbr99@gmail.com",
+            Role = "Admin"
+        };
+
+        _roleManagerRepository.RoleExistsAsync(createUserRequest.Role).Returns(Task.FromResult(true));
+
+        _userManagerRepository.CreateAsync(Arg.Any<AppUser>(), createUserRequest.Password)
+            .Returns(Task.FromResult(IdentityResult.Failed(new IdentityError { Description = "User creation failed" })));
+
+        // Act
+        var result = await _identityService.SignUpUser(createUserRequest);
+
+        // Assert
+        Assert.False(result.Succeed);
+        Assert.Equal("User creation failed", result.Message);
+    }
+    
+    [Fact]
+    public async Task SignUpUser_WhenRoleAssignmentFails_ReturnsFailResult()
+    {
+        // Arrange
+        var createUserRequest = new CreateUserRequest
+        {
+            UserName = "MobinBarfi",
+            Password = "Abc@123",
+            Email = "mobinbr99@gmail.com",
+            Role = "Admin"
+        };
+
+        _roleManagerRepository.RoleExistsAsync(createUserRequest.Role).Returns(Task.FromResult(true));
+
+        _userManagerRepository.CreateAsync(Arg.Any<AppUser>(), createUserRequest.Password)
+            .Returns(Task.FromResult(IdentityResult.Success));
+
+        _userManagerRepository.SetRoleAsync(Arg.Any<AppUser>(), createUserRequest.Role)
+            .Returns(Task.FromResult(IdentityResult.Failed(new IdentityError { Description = "Role assignment failed" })));
+
+        // Act
+        var result = await _identityService.SignUpUser(createUserRequest);
+
+        // Assert
+        Assert.False(result.Succeed);
+        Assert.Equal("Role assignment failed", result.Message);
+    }
+
+    [Fact]
+    public async Task SignUpUser_WhenUserIsCreatedAndRoleAssignedSuccessfully_ReturnsSuccessResult()
+    {
+        // Arrange
+        var createUserRequest = new CreateUserRequest
+        {
+            UserName = "MobinBarfi",
+            Password = "Abc@123",
+            Email = "mobinbr99@gmail.com",
+            Role = "Admin"
+        };
+
+        var appUser = new AppUser { UserName = createUserRequest.UserName };
+        var identityResultSuccess = IdentityResult.Success;
+
+        _roleManagerRepository.RoleExistsAsync(createUserRequest.Role)
+            .Returns(Task.FromResult(true));
+
+        _userManagerRepository.CreateAsync(Arg.Is<AppUser>(u => u.UserName == createUserRequest.UserName), createUserRequest.Password)
+            .Returns(Task.FromResult(identityResultSuccess));
+
+        _userManagerRepository.SetRoleAsync(Arg.Is<AppUser>(u => u.UserName == createUserRequest.UserName), createUserRequest.Role)
+            .Returns(Task.FromResult(identityResultSuccess));
+
+        var expectedResponse = new CreateUserResponse
+        {
+            UserName = createUserRequest.UserName,
+            Email = createUserRequest.Email,
+            FirstName = "",
+            LastName = "",
+            Role = createUserRequest.Role
+        };
+
+        // Act
+        var result = await _identityService.SignUpUser(createUserRequest);
+
+        // Assert
+        Assert.True(result.Succeed);
+        Assert.NotNull(result.Value);
+
+        var actualResponse = result.Value;
+
+        Assert.Equal(expectedResponse.UserName, actualResponse.UserName);
+        Assert.Equal(expectedResponse.Email, actualResponse.Email);
+        Assert.Equal(expectedResponse.FirstName, actualResponse.FirstName);
+        Assert.Equal(expectedResponse.LastName, actualResponse.LastName);
+        Assert.Equal(expectedResponse.Role, actualResponse.Role);
+    }
+    
+    // Login Tests
+    [Fact]
+    public async Task Login_WhenUsernameNotFound_ReturnsFailResult()
+    {
+        // Arrange
+        var loginUserRequest = new LoginUserRequest
+        {
+            UserName = "NonExistentUser",
+            Password = "Abc@123"
+        };
+
+        _userManagerRepository.FindByNameAsync(loginUserRequest.UserName).Returns(Task.FromResult<AppUser?>(null));
+
+        // Act
+        var result = await _identityService.Login(loginUserRequest);
+
+        // Assert
+        Assert.False(result.Succeed);
+        Assert.Equal("Invalid username/email!", result.Message);
+    }
+    
+    [Fact]
+    public async Task Login_WhenPasswordIncorrect_ReturnsFailResult()
+    {
+        // Arrange
+        var loginUserRequest = new LoginUserRequest
+        {
+            UserName = "MobinBarfi",
+            Password = "WrongPassword"
+        };
+
+        var appUser = new AppUser();
+        _userManagerRepository.FindByNameAsync(loginUserRequest.UserName).Returns(Task.FromResult(appUser));
+        _userManagerRepository.CheckPasswordAsync(appUser, loginUserRequest.Password).Returns(Task.FromResult(false));
+
+        // Act
+        var result = await _identityService.Login(loginUserRequest);
+
+        // Assert
+        Assert.False(result.Succeed);
+        Assert.Equal("Username/Email not found and/or password incorrect", result.Message);
+    }
+
+    [Fact]
+    public async Task Login_WhenLoginSucceeds_ReturnsSuccessResult()
+    {
+        // Arrange
+        var loginDto = new LoginDto
+        {
+            UserName = "MobinBarfi",
+            Password = "Abc@123"
+        };
+
+        var loginRequest = loginDto.ToLoginUserRequest();
+        var appUser = new AppUser
+        {
+            UserName = loginDto.UserName,
+            Email = "mobinbr99@gmail.com"
+        };
+        var role = "Admin";
+        var token = "valid.jwt.token";
+
+        var loginUserResponse = new LoginUserResponse
+        {
+            UserName = appUser.UserName,
+            Email = appUser.Email,
+            Token = token
+        };
+
+        // Set up the mock behavior
+        _userManagerRepository.FindByNameAsync(loginRequest.UserName)
+            .Returns(Task.FromResult(appUser));
+        _userManagerRepository.CheckPasswordAsync(appUser, loginRequest.Password)
+            .Returns(Task.FromResult(true));
+        _userManagerRepository.GetRoleAsync(appUser)
+            .Returns(Task.FromResult(role));
+        _jwtGenerator.GenerateToken(appUser, role)
+            .Returns(token);
+
+        // Act
+        var result = await _identityService.Login(loginRequest);
+
+        // Assert
+        Assert.True(result.Succeed);
+        var loginResponse = result.Value;
+
+        Assert.NotNull(loginResponse);
+        Assert.Equal(loginUserResponse.UserName, loginResponse.UserName);
+        Assert.Equal(loginUserResponse.Email, loginResponse.Email);
+        Assert.Equal(loginUserResponse.Token, loginResponse.Token);
+    }
+    
+    // ChangeRole Tests
+    [Fact]
+    public async Task ChangeRole_WhenRoleDoesNotExist_ReturnsFailResult()
+    {
+        // Arrange
+        var changeRoleRequest = new ChangeRoleRequest
+        {
+            UserName = "MobinBarfi",
+            Role = "NonExistentRole"
+        };
+
+        _roleManagerRepository.RoleExistsAsync(changeRoleRequest.Role).Returns(Task.FromResult(false));
+
+        // Act
+        var result = await _identityService.ChangeRole(changeRoleRequest);
+
+        // Assert
+        Assert.False(result.Succeed);
+        Assert.Equal("role does not exist", result.Message);
+    }
+    
+    [Fact]
+    public async Task ChangeRole_WhenUserDoesNotExist_ReturnsFailResult()
+    {
+        // Arrange
+        var changeRoleRequest = new ChangeRoleRequest
+        {
+            UserName = "NonExistentUser",
+            Role = "Admin"
+        };
+
+        _roleManagerRepository.RoleExistsAsync(changeRoleRequest.Role).Returns(Task.FromResult(true));
+        _userManagerRepository.FindByNameAsync(changeRoleRequest.UserName).Returns(Task.FromResult<AppUser?>(null));
+
+        // Act
+        var result = await _identityService.ChangeRole(changeRoleRequest);
+
+        // Assert
+        Assert.False(result.Succeed);
+        Assert.Equal("Invalid username", result.Message);
+    }
+
+    [Fact]
+    public async Task ChangeRole_WhenOperationSucceeds_ReturnsSuccessResult()
+    {
+        // Arrange
+        var changeRoleRequest = new ChangeRoleRequest
+        {
+            UserName = "MobinBarfi",
+            Role = "Admin"
+        };
+
+        var appUser = new AppUser();
+
+        _roleManagerRepository.RoleExistsAsync(changeRoleRequest.Role).Returns(Task.FromResult(true));
+        _userManagerRepository.FindByNameAsync(changeRoleRequest.UserName).Returns(Task.FromResult(appUser));
+        _userManagerRepository.ChangeRoleAsync(appUser, changeRoleRequest.Role).Returns(Task.FromResult(IdentityResult.Success));
+
+        // Act
+        var result = await _identityService.ChangeRole(changeRoleRequest);
+
+        // Assert
+        Assert.True(result.Succeed);
+    }
+    
+    // GetUsers Tests
+    [Fact]
+    public async Task GetUsersAsync_ReturnsUserListWithRoles()
+    {
+        // Arrange
+        var users = new List<AppUser>
+        {
+            new AppUser { UserName = "User1", Email = "user1@example.com" },
+            new AppUser { UserName = "User2", Email = "user2@example.com" }
+        };
+
+        var roles = new List<string> { "Admin", "User" };
+
+        var userResponses = new List<GetUserResponse>
+        {
+            new GetUserResponse { UserName = "User1", Email = "user1@example.com", Role = "Admin" },
+            new GetUserResponse { UserName = "User2", Email = "user2@example.com", Role = "User" }
+        };
+
+        // Mock the repository methods
+        _userManagerRepository.GetUsersAsync()
+            .Returns(Task.FromResult(users));
+        
+        _userManagerRepository.GetRoleAsync(users[0])
+            .Returns(Task.FromResult(roles[0]));
+
+        _userManagerRepository.GetRoleAsync(users[1])
+            .Returns(Task.FromResult(roles[1]));
+
+        // Act
+        var result = await _identityService.GetUsersAsync();
+
+        // Assert
+        Assert.NotNull(result);
+        Assert.Equal(2, result.Count);
+        Assert.Contains(result, r => r.UserName == "User1" && r.Role == "Admin");
+        Assert.Contains(result, r => r.UserName == "User2" && r.Role == "User");
+    }
+}
\ No newline at end of file
diff --git a/test/Web.UnitTests/Controllers/IdentityControllerTests.cs b/test/Web.UnitTests/Controllers/IdentityControllerTests.cs
index d0d83c6..2a602b7 100644
--- a/test/Web.UnitTests/Controllers/IdentityControllerTests.cs
+++ b/test/Web.UnitTests/Controllers/IdentityControllerTests.cs
@@ -2,6 +2,8 @@
 using Application.DTOs;
 using Application.DTOs.Identity;
 using Application.DTOs.Identity.ChangeRole;
+using Application.DTOs.Identity.CreateUser;
+using Application.DTOs.Identity.LoginUser;
 using Application.Interfaces.Services;
 using Domain.Constants;
 using Domain.Entities;