Update JUnit Test And Developer Guide For Edit Command

docs/DeveloperGuide.md

@@ -148,6 +148,45 @@ and modifications.
 The following sequence diagram shows how the view transaction operation works:
 <img src="images/ViewSequenceDiagram.png" width="600" />
 
+### `edit` Transaction Feature
+
+#### I. Architecture-Level Design
+This section details the components involved in the `edit` transaction feature:
+1. **Parser**: Interprets user input and creates an `EditCommand` object with the appropriate parameters.
+2. **EditCommand**: Inherits from the `Command` class, encapsulating the "edit" action along with the index and the new transaction details.
+3. **Nuscents**: The main class that invokes the `execute()` method of `EditCommand`.
+4. **TransactionList**: Manages a collection of transactions and facilitates the replacement of a specific transaction.
+5. **Transaction**: The superclass for different types of transactions such as `Expense` and `Allowance`.
+6. **UI**: Manages interactions with the user and displays messages regarding the editing process.
+
+#### II. Component-Level Design
+Here's how each component plays a role in the `edit` transaction feature:
+1. **Parser**: Extracts the index and transaction details from the input and uses other parsing methods to create a `Transaction` object.
+2. **EditCommand**: Contains the logic to replace an existing transaction in the `TransactionList`.
+3. **Nuscents**: Calls the `execute()` method of `EditCommand` and handles exceptions that may arise.
+4. **TransactionList**: Provides the `editTransaction(index, transaction)` method to update transactions at a specific index.
+5. **Transaction**: Abstract representation of a financial record that can be edited.
+6. **UI**: Outputs the result of the edit operation and any error messages.
+
+#### III. Alternatives Considered
+An alternative design considered was to have `EditCommand` interact directly with `Transaction` objects to modify their fields. However, this approach was discarded in favor of having a clear separation where `TransactionList` manages all transactions, maintaining encapsulation and single responsibility principles.
+
+#### IV. Usage Scenario Example
+**Step 1**: User starts the application, and `TransactionList` is initialized with existing transactions.
+
+**Step 2**: The user inputs `edit 2 expense /amt 100 /date 01-01-2023 /desc Movie night`. The `Parser` reads the input, separating the index from the rest of the transaction details.
+
+**Step 3**: `Parser` calls `parseExpense` to create an `Expense` object and then constructs an `EditCommand` with the index and the new `Expense`.
+
+**Step 4**: `Nuscents` receives and invokes the `EditCommand`'s `execute()` method.
+
+**Step 5**: Inside `execute()`, `EditCommand` uses `TransactionList`'s `editTransaction(index, transaction)` to replace the existing transaction.
+
+**Step 6**: `TransactionList` updates the transaction at the given index. If the index is invalid, an exception is thrown.
+
+**Step 7**: Upon successful update, `UI` displays a confirmation message. If an error occurs, an error message is shown instead.  
+
+
 ### `helpCommand` Feature
 
 #### I. Architecture-Level Design

src/main/java/seedu/nuscents/ui/Messages.java

@@ -38,7 +38,6 @@ public class Messages {
     public static final String MESSAGE_INVALID_INDEX = "OOPS!!! This is an invalid transaction index.";
     public static final String MESSAGE_INVALID_INDEX_ARGUMENTS = "OOPS!!! The input should consist only of digits.";
     public static final String MESSAGE_EMPTY_LIST = "You have not made any transactions!";
-    public static final String MESSAGE_EMPTY_KEYWORD = "OOPS!!! The keyword of a find command cannot be empty.";
     public static final String MESSAGE_EMPTY_BUDGET = "OOPS!!! The budget amount cannot be empty.";
     public static final String MESSAGE_INVALID_BUDGET = "OOPS!!! The budget amount requires a +ve valid float value";
     public static final String MESSAGE_INVALID_BUDGET_FLOAT_DP = "OOPS!!! The budget amount cannot exceed 2 d.p.";

src/test/java/seedu/nuscents/parser/ParserTest.java

@@ -288,6 +288,17 @@ public void parseFilterCategory_invalidCategory_exceptionThrown() throws Nuscent
         assertEquals(Messages.MESSAGE_UNKNOWN_FILTER_CATEGORY, exception.getMessage());
     }
 
+    @Test
+    public void parseEdit_emptyArguments_exceptionThrown() {
+        String input = "edit 2";
+        Exception exception = assertThrows(NuscentsException.class, () -> {
+            Parser.parseEdit(input);
+        });
+        assertEquals(Messages.MESSAGE_EMPTY_EDIT, exception.getMessage());
+    }
+
+
+
     @Test
     public void parseCommand_helpCommandWithCorrectInput_returnsHelpCommand() throws Exception {
         Command result = Parser.parseCommand("help", null);