Add additional Parser testcases

src/main/java/duke/Duke.java

@@ -14,10 +14,11 @@
  */
 public class Duke {
 
+    public static final String WELCOME_MESSAGE = "Hello! I'm Duke. What would you like to do today?";
+
     /** The file path where the data of the chatbot is stored */
     private static final String FILE_PATH = "data/tasks.txt";
 
-
     private final Storage storage;
     private final TaskList tasks;
 

src/main/java/duke/gui/MainWindow.java

@@ -1,5 +1,7 @@
 package duke.gui;
 
+import static duke.Duke.WELCOME_MESSAGE;
+
 import duke.Duke;
 import duke.command.CommandResult;
 import duke.data.exception.DukeException;
@@ -25,9 +27,13 @@ public class MainWindow extends AnchorPane {
 
     private Duke duke;
 
+    /**
+     * Initializes the main window with the given welcome message.
+     */
     @FXML
     public void initialize() {
         scrollPane.vvalueProperty().bind(dialogContainer.heightProperty());
+        addDukeDialog(WELCOME_MESSAGE);
     }
 
     public void setDuke(Duke d) {

src/main/resources/view/UserDialogBox.fxml

@@ -15,10 +15,6 @@
          <font>
             <Font name="Source Code Pro" size="12.0" />
          </font></Label>
-        <ImageView fx:id="displayPicture" fitHeight="60.0" fitWidth="60.0" pickOnBounds="true" preserveRatio="true">
-         <image>
-            <Image url="@../images/DaUser.png" />
-         </image></ImageView>
     </children>
     <padding>
         <Insets bottom="15.0" left="15.0" right="15.0" top="15.0" />

src/test/java/duke/data/task/TaskListTest.java

@@ -10,22 +10,23 @@
 import org.junit.jupiter.api.Test;
 
 import duke.data.exception.DukeException;
+import duke.data.exception.InvalidTaskIndexException;
 
 public class TaskListTest {
 
     @Test
-    public void removeTask_invalidIndex_throwsDukeException() {
+    public void remove_invalidIndex_throwsInvalidTaskIndexException() {
         TaskList taskList = new TaskList(
                 new Todo("todo"),
                 new Deadline("deadline", LocalDate.now()),
                 new Event("event", LocalDate.now(), LocalDate.now())
         );
-        assertThrows(DukeException.class, () -> taskList.remove(-1));
-        assertThrows(DukeException.class, () -> taskList.remove(4));
+        assertThrows(InvalidTaskIndexException.class, () -> taskList.remove(-1));
+        assertThrows(InvalidTaskIndexException.class, () -> taskList.remove(4));
     }
 
     @Test
-    public void removeTask_validIndexIndex_taskNotInList() {
+    public void remove_validIndexIndex_taskNotInList() {
         Task toRemove = new Todo("toRemove");
         TaskList taskList = new TaskList(
                 new Todo("todo"),