Created view handler for CommandErrorView

src/test/java/guitests/guihandles/CommandErrorViewHandle.java

@@ -0,0 +1,52 @@
+package guitests.guihandles;
+
+import guitests.GuiRobot;
+import javafx.scene.Node;
+import javafx.scene.layout.GridPane;
+import javafx.stage.Stage;
+import seedu.todo.TestApp;
+import seedu.todo.testutil.UiTestUtil;
+
+//@@author A0135805H
+/**
+ * A handler for retrieving error messages to user via {@link seedu.todo.ui.view.CommandErrorView}
+ */
+public class CommandErrorViewHandle extends GuiHandle {
+    /* Constants */
+    private static final String NON_FIELD_ERROR_GRID_ID = "#nonFieldErrorGrid";
+    private static final String FIELD_ERROR_GRID_ID = "#fieldErrorGrid";
+    private static final String ERROR_VIEW_PLACEHOLDER_ID = "#commandErrorViewPlaceholder";
+
+    /**
+     * Constructs a handle to the {@link CommandFeedbackViewHandle}
+     *
+     * @param guiRobot {@link GuiRobot} for the current GUI test.
+     * @param primaryStage The stage where the views for this handle is located.
+     */
+    public CommandErrorViewHandle(GuiRobot guiRobot, Stage primaryStage) {
+        super(guiRobot, primaryStage, TestApp.APP_TITLE);
+    }
+
+    /**
+     * Returns true if the placeholder is visible.
+     */
+    public boolean isVisible() {
+        Node placeholder = getNode(ERROR_VIEW_PLACEHOLDER_ID);
+        return UiTestUtil.isDisplayed(placeholder);
+    }
+
+    /**
+     * Returns true if the placeholder has messages displayed.
+     */
+    public boolean hasErrorMessages() {
+        int numOfErrorMessages = 0;
+
+        GridPane errorField = (GridPane) getNode(FIELD_ERROR_GRID_ID);
+        GridPane nonErrorField = (GridPane) getNode(NON_FIELD_ERROR_GRID_ID);
+
+        numOfErrorMessages += errorField.getChildren().size() / 2;
+        numOfErrorMessages += nonErrorField.getChildren().size() / 2;
+
+        return numOfErrorMessages > 0;
+    }
+}

src/test/java/guitests/guihandles/MainGuiHandle.java

@@ -30,4 +30,8 @@ public CommandFeedbackViewHandle getCommandFeedbackView() {
     public CommandPreviewViewHandle getCommandPreviewView() {
         return new CommandPreviewViewHandle(guiRobot, primaryStage);
     }
+
+    public CommandErrorViewHandle getCommandErrorView() {
+        return new CommandErrorViewHandle(guiRobot, primaryStage);
+    }
 }