Reorganize tests by API and service concerns

RpgRoller.Tests/Api/AuthApiTests.cs

@@ -0,0 +1,35 @@
+using Microsoft.AspNetCore.Mvc.Testing;
+
+namespace RpgRoller.Tests;
+
+public sealed class AuthApiTests : ApiTestBase
+{
+    public AuthApiTests(WebApplicationFactory<Program> factory)
+        : base(factory)
+    {
+    }
+
+    [Fact]
+    public async Task RegisterLoginAndMeFlow_WorksWithDuplicateUsernameGuard()
+    {
+        using var factory = CreateFactory(4, 4, 4);
+        using var client = factory.CreateClient(new WebApplicationFactoryClientOptions { AllowAutoRedirect = false });
+
+        var registerResult = await RegisterAsync(client, "alice", "Password123", "Alice");
+        Assert.Equal("alice", registerResult.Username);
+
+        var duplicate = await client.PostAsJsonAsync("/api/auth/register", new RegisterRequest("alice", "Password123", "Alice 2"));
+        Assert.Equal(HttpStatusCode.BadRequest, duplicate.StatusCode);
+
+        var loginResult = await client.PostAsJsonAsync("/api/auth/login", new LoginRequest("alice", "Password123"));
+        Assert.Equal(HttpStatusCode.OK, loginResult.StatusCode);
+
+        var me = await GetAsync<MeResponse>(client, "/api/me");
+        Assert.Equal(registerResult.Id, me.User.Id);
+        Assert.Null(me.ActiveCharacterId);
+        Assert.Null(me.CurrentCampaignId);
+
+        var invalidLogin = await client.PostAsJsonAsync("/api/auth/login", new LoginRequest("alice", "wrong-password"));
+        Assert.Equal(HttpStatusCode.BadRequest, invalidLogin.StatusCode);
+    }
+}