Add tests

BudgetApp/Services/AccountService.cs

@@ -3,14 +3,9 @@ using BudgetApp.Data;
 
 namespace BudgetApp.Services;
 
-public class AccountService
+public class AccountService(ApplicationDbContext db)
 {
-    private readonly ApplicationDbContext _db;
-
-    public AccountService(ApplicationDbContext db)
-    {
-        _db = db;
-    }
+    private readonly ApplicationDbContext _db = db;
 
     public async Task<List<Account>> GetAccountsAsync(string userId)
     {