Improve testing and some cleanup refactoring.

wolverine/a-frame-architecture/FinancialApi.Domain/Aggregates/BalancedJournal.cs

@@ -6,7 +6,10 @@ public record BalancedJournal
 {
     public JournalEntry Entry { get; }
 
-    private BalancedJournal(JournalEntry entry) => Entry = entry;
+    private BalancedJournal(JournalEntry entry)
+    {
+        Entry = entry;
+    }
 
     public static BalancedJournal Create(Guid id, string description, DateTimeOffset createdAt, List<JournalLine> lines)
     {
@@ -22,7 +25,7 @@ public record BalancedJournal
             );
         }
 
-        return new(new JournalEntry(id, description, createdAt, lines));
+        return new BalancedJournal(new JournalEntry(id, description, createdAt, lines));
     }
 
     public static BalancedJournal CreateReversal(JournalEntry original, string reason, DateTimeOffset now)

wolverine/a-frame-architecture/FinancialApi.Domain/Entities/Account.cs

@@ -1,54 +1,32 @@
 namespace FinancialApi.Domain.Entities;
 
-public record Account(int Id, decimal Balance, string AccountType)
+public enum AccountType
+{
+    Liability,
+    Debit,
+    Credit,
+    Revenue
+}
+
+public record Account(int Id, decimal Balance, AccountType Type)
 {
     public Account ApplyPosting(decimal amount, EntryType entryType)
     {
         if (amount <= 0)
         {
-            throw new ArgumentException("Credit amount must be positive.");
+            throw new ArgumentException("Amount must be positive.");
         }
 
-        var newBalance = Balance;
-        if (AccountType == "Revenue")
-        {
-            newBalance = entryType == EntryType.Credit ? newBalance + amount : newBalance - amount;
-        }
-        else
-        {
-            newBalance = entryType == EntryType.Debit ? newBalance - amount : newBalance + amount;
-        }
+        var newBalance = entryType == EntryType.Credit ? Balance + amount : Balance - amount;
+        ;
 
-        if (newBalance < 0 && AccountType == "Liability")
+        if (newBalance < 0 && Type is AccountType.Liability or AccountType.Debit or AccountType.Revenue)
         {
-            throw new InvalidOperationException("Insufficient funds.");
+            throw new InsufficientFundsException("Insufficient funds.");
         }
 
         return this with { Balance = newBalance };
     }
+}
 
-    public Account Debit(decimal amount)
-    {
-        if (amount <= 0)
-        {
-            throw new ArgumentException("Debit amount must be positive.");
-        }
-
-        if (Balance - amount < 0)
-        {
-            throw new InvalidOperationException("Insufficient funds.");
-        }
-
-        return this with { Balance = Balance - amount };
-    }
-
-    public Account Credit(decimal amount)
-    {
-        if (amount <= 0)
-        {
-            throw new ArgumentException("Credit amount must be positive.");
-        }
-
-        return this with { Balance = Balance + amount };
-    }
-}
+public class InsufficientFundsException(string insufficientFunds) : Exception(insufficientFunds);