diff --git a/src/FiscalOS.API/Login/Endpoint.cs b/src/FiscalOS.API/Login/Endpoint.cs
index a7e9e9e..89e7117 100644
--- a/src/FiscalOS.API/Login/Endpoint.cs
+++ b/src/FiscalOS.API/Login/Endpoint.cs
@@ -11,8 +11,30 @@ internal static class Endpoint
 
   private static async Task<IResult> HandleAsync([FromBody] LoginRequest loginRequest)
   {
-    Console.WriteLine(loginRequest.Username);
-    Console.WriteLine(loginRequest.Password);
+    const string ADMIN_USERNAME = "Stevan";
+    const string ADMIN_PASSWORD = "@Password1";
+
+    // TODO: Implement actual auth flow
+    // 1. We want to make sure that
+    //    the user exists
+    // 2. We want to make sure that
+    //    tha the password is correct
+    // 3. We want to issue an access token
+    //    with a refresh token
+    // 4. We want to store the refresh
+    //    token
+    // 5. We want to set the refresh
+    //    token in a cookie
+
+    // TODO: Things we need
+    // 1. We need a user model
+    // 2. We need a refresh token model
+
+    if (loginRequest.Username is not ADMIN_USERNAME || loginRequest.Password is not ADMIN_PASSWORD)
+    {
+      return Results.Unauthorized();
+    }
+
     return Results.Ok();
   }
 }
\ No newline at end of file
diff --git a/tests/FiscalOS.API.Tests/Integration/LoginTests.cs b/tests/FiscalOS.API.Tests/Integration/LoginTests.cs
index aa2f856..0a79a3b 100644
--- a/tests/FiscalOS.API.Tests/Integration/LoginTests.cs
+++ b/tests/FiscalOS.API.Tests/Integration/LoginTests.cs
@@ -1,28 +1,127 @@
-using System.Net.Http.Json;
-
-using Microsoft.AspNetCore.Mvc;
-
 namespace FiscalOS.API.Tests.Integration;
 
 public class LoginTests(TestApi testApi) : IClassFixture<TestApi>
 {
   private readonly TestApi _testApi = testApi;
 
-  [Fact]
-  public async Task Login_WhenUserSubmitsWithoutUsernameOrPassword_ItShouldReturn400WithProblemDetails()
+  [Theory]
+  [ClassData<LoginValidationTestCases>]
+  public async Task Login_WhenUserSubmitsInvalidRequest_ItShouldReturn400WithProblemDetails(LoginValidationTestCase tc)
   {
     var client = _testApi.CreateClient();
 
-    var res = await client.PostAsJsonAsync("/login", new { }, TestContext.Current.CancellationToken);
+    var req = new
+    {
+      username = tc.Username,
+      password = tc.Password,
+    };
 
-    res.StatusCode.Should().Be(System.Net.HttpStatusCode.BadRequest);
+    var res = await client.PostAsJsonAsync("/login", req, TestContext.Current.CancellationToken);
+
+    res.StatusCode.Should().Be(HttpStatusCode.BadRequest);
 
     var problem = await res.Content.ReadFromJsonAsync<ValidationProblemDetails>(TestContext.Current.CancellationToken);
 
-    problem!.Errors.Should().BeEquivalentTo(new Dictionary<string, string[]>()
+    problem!.Errors.Should().BeEquivalentTo(tc.ExpectedErrors);
+  }
+
+  [Fact]
+  public async Task Login_WhenUserCredentialsAreIncorrect_ItShouldReturn401WithProblemDetails()
+  {
+    var client = _testApi.CreateClient();
+
+    var req = new
     {
-      ["Username"] = ["The Username field is required."],
-      ["Password"] = ["The Password field is required."]
-    });
+      username = "Test",
+      password = "@Password2",
+    };
+
+    var res = await client.PostAsJsonAsync("/login", req, TestContext.Current.CancellationToken);
+
+    res.StatusCode.Should().Be(HttpStatusCode.Unauthorized);
+  }
+}
+
+
+public class LoginValidationTestCases : TheoryData<LoginValidationTestCase>
+{
+  public LoginValidationTestCases()
+  {
+    Add(new LoginValidationTestCase(
+      "No username or password",
+      string.Empty,
+      string.Empty,
+      new Dictionary<string, string[]>()
+      {
+        ["Username"] = ["The Username field is required."],
+        ["Password"] = ["The Password field is required."]
+      }
+    ));
+
+    Add(new LoginValidationTestCase(
+      "No username",
+      string.Empty,
+      "@Password1",
+      new Dictionary<string, string[]>()
+      {
+        ["Username"] = ["The Username field is required."],
+      }
+    ));
+
+    Add(new LoginValidationTestCase(
+      "No password",
+      "Stevan",
+      string.Empty,
+      new Dictionary<string, string[]>()
+      {
+        ["Password"] = ["The Password field is required."]
+      }
+    ));
+  }
+}
+
+public record LoginValidationTestCase : IXunitSerializable
+{
+  public string Name { get; private set; } = string.Empty;
+  public string Username { get; private set; } = string.Empty;
+  public string Password { get; private set; } = string.Empty;
+  public Dictionary<string, string[]> ExpectedErrors { get; private set; } = [];
+
+  public override string ToString()
+  {
+    return Name;
+  }
+
+  public LoginValidationTestCase()
+  {
+  }
+
+  public LoginValidationTestCase(
+    string name,
+    string username,
+    string password,
+    Dictionary<string, string[]> expectedErrors
+  )
+  {
+    Name = name;
+    Username = username;
+    Password = password;
+    ExpectedErrors = expectedErrors;
+  }
+
+  public void Deserialize(IXunitSerializationInfo info)
+  {
+    Name = info.GetValue<string>(nameof(Name)) ?? string.Empty;
+    Username = info.GetValue<string>(nameof(Username)) ?? string.Empty;
+    Password = info.GetValue<string>(nameof(Password)) ?? string.Empty;
+    ExpectedErrors = info.GetValue<Dictionary<string, string[]>>(nameof(ExpectedErrors)) ?? [];
+  }
+
+  public void Serialize(IXunitSerializationInfo info)
+  {
+    info.AddValue(nameof(Name), Name);
+    info.AddValue(nameof(Username), Username);
+    info.AddValue(nameof(Password), Password);
+    info.AddValue(nameof(ExpectedErrors), ExpectedErrors);
   }
 }
\ No newline at end of file