Add assertions to Deadline and Event

src/main/java/duke/command/AddDeadlineCommand.java

@@ -23,6 +23,10 @@ public class AddDeadlineCommand extends Command {
      * @param by The due date of the deadline task.
      */
     public AddDeadlineCommand(String taskDescription, String by) {
+        assert by.split(" ").length == 3 : "by String should contain should have 3 fields";
+        assert by.split(" ")[0].length() == 3 : "Month is represented as 3 letters";
+        assert by.split(" ")[1].length() <= 2 : "Date format should not have more than 2 characters";
+        assert by.split(" ")[2].length() == 4 : "Year format should have 4 characters";
         this.taskDescription = taskDescription;
         this.by = by;
     }

src/main/java/duke/command/AddEventCommand.java

@@ -26,6 +26,14 @@ public class AddEventCommand extends Command {
      */
     public AddEventCommand(String taskDescription, String from, String to) {
         this.taskDescription = taskDescription;
+        assert from.split(" ").length == 3 : "by String should contain should have 3 fields";
+        assert from.split(" ")[0].length() == 3 : "Month is represented as 3 letters";
+        assert from.split(" ")[1].length() <= 2 : "Date format should not have more than 2 characters";
+        assert from.split(" ")[2].length() == 4 : "Year format should have 4 characters";
+        assert to.split(" ").length == 3 : "by String should contain should have 3 fields";
+        assert to.split(" ")[0].length() == 3 : "Month is represented as 3 letters";
+        assert to.split(" ")[1].length() <= 2 : "Date format should not have more than 2 characters";
+        assert to.split(" ")[2].length() == 4 : "Year format should have 4 characters";
         this.from = from;
         this.to = to;
     }

src/main/java/duke/parser/Parser.java

@@ -44,6 +44,7 @@ public static Command parse(String input) throws DukeException {
             if (eventData.length < 2) {
                 throw new DukeException("An event requires a /from (timedate) descriptor");
             }
+
             String[] period = eventData[1].split("/to ");
             if (period.length < 2) {
                 throw new DukeException("An event requires a /to (timedate) descriptor");

src/main/java/duke/task/Deadline.java

@@ -21,6 +21,10 @@ public class Deadline extends Task {
      */
     public Deadline(String task, boolean isDone, String due) throws DateTimeException {
         super(task, isDone);
+        assert due.split(" ").length == 3 : "by String should contain should have 3 fields";
+        assert due.split(" ")[0].length() == 3 : "Month is represented as 3 letters";
+        assert due.split(" ")[1].length() <= 2 : "Date format should not have more than 2 characters";
+        assert due.split(" ")[2].length() == 4 : "Year format should have 4 characters";
         this.due = due;
     }
 

src/main/java/duke/task/Event.java

@@ -24,6 +24,14 @@ public class Event extends Task {
      */
     public Event(String task, boolean isDone, String from, String to) throws DateTimeException {
         super(task, isDone);
+        assert from.split(" ").length == 3 : "by String should contain should have 3 fields";
+        assert from.split(" ")[0].length() == 3 : "Month is represented as 3 letters";
+        assert from.split(" ")[1].length() <= 2 : "Date format should not have more than 2 characters";
+        assert from.split(" ")[2].length() == 4 : "Year format should have 4 characters";
+        assert to.split(" ").length == 3 : "by String should contain should have 3 fields";
+        assert to.split(" ")[0].length() == 3 : "Month is represented as 3 letters";
+        assert to.split(" ")[1].length() <= 2 : "Date format should not have more than 2 characters";
+        assert to.split(" ")[2].length() == 4 : "Year format should have 4 characters";
         this.from = from;
         this.to = to;
     }