Working on the UserRepository functionality

+ Tests
+ QueryableExtensions. It is an add-on that allows you to implement exceptions if the returned List would be empty.

Govor.API.Tests/IntegrationTests/EF/Repositories/UsersRepositoryTests.cs

@@ -3,6 +3,7 @@ using Govor.Core.Infrastructure.Validators;
 using Govor.Core.Models;
 using Govor.Data;
 using Govor.Data.Repositories;
+using Govor.Data.Repositories.Exceptions;
 using Microsoft.EntityFrameworkCore;
 
 namespace Govor.API.Tests.IntegrationTests.EF.Repositories;
@@ -53,5 +54,75 @@ public class UsersRepositoryTests
         Assert.That(result.Count, Is.EqualTo(users.Count));
         Assert.That(result.Select(u => u.Id), Is.EquivalentTo(users.Select(u => u.Id)));
         Assert.That(result.Select(u => u.Username), Is.EquivalentTo(users.Select(u => u.Username)));
-    } 
+    }
+
+    [Test]
+    public async Task Given_ValidUserId_When_FindById_Then_Returns_User()
+    {
+        // Arrange
+        var user  = _fixture.Create<User>();
+        await using var context = new GovorDbContext(_options);
+        var userRepository = new UsersRepository(context, _userValidator);
+        
+        context.Users.Add(user);
+        await context.SaveChangesAsync();
+        
+        // Act 
+        var result = await userRepository.FindById(user.Id);
+        
+        // Assert 
+        Assert.That(result, Is.Not.Null);
+        Assert.That(result.Username, Is.EqualTo(user.Username));
+        Assert.That(result.Id, Is.EqualTo(user.Id));
+    }
+    
+    [Test]
+    public async Task Given_InvalidUserId_When_FindById_Should_Throw_NotFoundException()
+    {
+        // Arrange 
+        var id = Guid.NewGuid();
+        
+        await using var context = new GovorDbContext(_options);
+        var userRepository = new UsersRepository(context, _userValidator);
+        
+        // Act & Assert  
+        Assert.ThrowsAsync<NotFoundByKeyException<Guid>>(async () => await userRepository.FindById(id));
+    }
+    
+    [Test]
+    public async Task Given_RangeValidUserId_When_FindByRangeId_Then_Returns_Users()
+    {
+        // Arrange 
+        var random = new Random();
+        var users = _fixture.CreateMany<User>(random.Next(2, 10)).ToList();
+        
+        await using var context = new GovorDbContext(_options);
+        var userRepository = new UsersRepository(context, _userValidator);
+        
+        context.Users.AddRange(users);
+        await context.SaveChangesAsync();
+        
+        // Act 
+        var result = await userRepository.FindByRangeId(users.Select(u => u.Id));
+        
+        // Assert 
+        Assert.That(result, Is.Not.Null);
+        Assert.That(result.Count, Is.EqualTo(users.Count));
+        Assert.That(result.Select(r => r.Id), Is.EquivalentTo(users.Select(u => u.Id)));
+        Assert.That(result.Select(u => u.Username), Is.EquivalentTo(users.Select(u => u.Username)));
+    }
+    
+    [Test]
+    public async Task Given_InvalidRangeId_When_FindByRangeId_Should_Throw_NotFoundException()
+    {
+        // Arrange 
+        var random = new Random();
+        var ids = _fixture.CreateMany<Guid>(random.Next(2, 10)).ToList();
+        
+        await using var context = new GovorDbContext(_options);
+        var userRepository = new UsersRepository(context, _userValidator);
+        
+        // Act & Assert 
+        Assert.ThrowsAsync<NotFoundByKeyException<IEnumerable<Guid>>>(async () => await userRepository.FindByRangeId(ids));
+    }
 }