diff --git a/src/main/java/seedu/todo/controllers/CompleteTaskController.java b/src/main/java/seedu/todo/controllers/CompleteTaskController.java
index 311623d73bd2..dd57b82025fb 100644
--- a/src/main/java/seedu/todo/controllers/CompleteTaskController.java
+++ b/src/main/java/seedu/todo/controllers/CompleteTaskController.java
@@ -18,11 +18,11 @@ public class CompleteTaskController extends Controller {
     private static final String COMMAND_SYNTAX = "complete <index>";
     private static final String COMMAND_KEYWORD = "complete";
     
-    private static final String MESSAGE_SUCCESS = "Task marked as complete!";
-    private static final String MESSAGE_INVALID_ITEM = "Could not mark task as complete: Invalid index provided!";
-    private static final String MESSAGE_CANNOT_COMPLETE_EVENT = "An event cannot be marked as complete!";
-    private static final String MESSAGE_ALREADY_COMPLETED = "Could not mark task as complete: Task is already complete!";
-    private static final String MESSAGE_COULD_NOT_SAVE = "Could not mark task as complete: An error occured while saving the database file.";
+    public static final String MESSAGE_SUCCESS = "Task marked as complete!";
+    public static final String MESSAGE_INVALID_ITEM = "Could not mark task as complete: Invalid index provided!";
+    public static final String MESSAGE_CANNOT_COMPLETE_EVENT = "An event cannot be marked as complete!";
+    public static final String MESSAGE_ALREADY_COMPLETED = "Could not mark task as complete: Task is already complete!";
+    public static final String MESSAGE_COULD_NOT_SAVE = "Could not mark task as complete: An error occured while saving the database file.";
     
     private static CommandDefinition commandDefinition =
             new CommandDefinition(NAME, DESCRIPTION, COMMAND_SYNTAX, COMMAND_KEYWORD); 
diff --git a/src/main/java/seedu/todo/controllers/UncompleteTaskController.java b/src/main/java/seedu/todo/controllers/UncompleteTaskController.java
index 241dfdaf9b17..0a5227fe55f7 100644
--- a/src/main/java/seedu/todo/controllers/UncompleteTaskController.java
+++ b/src/main/java/seedu/todo/controllers/UncompleteTaskController.java
@@ -18,11 +18,11 @@ public class UncompleteTaskController extends Controller {
     private static final String COMMAND_SYNTAX = "uncomplete <index>";
     private static final String COMMAND_KEYWORD = "uncomplete";
 
-    private static final String MESSAGE_SUCCESS = "Task marked as incomplete!";
-    private static final String MESSAGE_INVALID_ITEM = "Could not mark task as incomplete: Invalid index provided!";
-    private static final String MESSAGE_CANNOT_UNCOMPLETE_EVENT = "An event cannot be marked as incomplete!";
-    private static final String MESSAGE_ALREADY_INCOMPLETE = "Could not mark task as incomplete: Task is not completed!";
-    private static final String MESSAGE_COULD_NOT_SAVE = "Could not mark task as incomplete: An error occured while saving the database file.";
+    public static final String MESSAGE_SUCCESS = "Task marked as incomplete!";
+    public static final String MESSAGE_INVALID_ITEM = "Could not mark task as incomplete: Invalid index provided!";
+    public static final String MESSAGE_CANNOT_UNCOMPLETE_EVENT = "An event cannot be marked as incomplete!";
+    public static final String MESSAGE_ALREADY_INCOMPLETE = "Could not mark task as incomplete: Task is not completed!";
+    public static final String MESSAGE_COULD_NOT_SAVE = "Could not mark task as incomplete: An error occured while saving the database file.";
     
     
     private static CommandDefinition commandDefinition =
diff --git a/src/test/java/seedu/todo/guitests/CompleteUncompleteTaskTest.java b/src/test/java/seedu/todo/guitests/CompleteUncompleteTaskTest.java
new file mode 100644
index 000000000000..e41c13990165
--- /dev/null
+++ b/src/test/java/seedu/todo/guitests/CompleteUncompleteTaskTest.java
@@ -0,0 +1,126 @@
+package seedu.todo.guitests;
+
+import static org.junit.Assert.assertEquals;
+
+import java.time.LocalDateTime;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import seedu.todo.commons.util.DateUtil;
+import seedu.todo.controllers.CompleteTaskController;
+import seedu.todo.controllers.UncompleteTaskController;
+import seedu.todo.models.Event;
+import seedu.todo.models.Task;
+
+/**
+ * @@author A0093907W
+ */
+public class CompleteUncompleteTaskTest extends GuiTest {
+    
+    private final LocalDateTime oneDayFromNow = LocalDateTime.now().plusDays(1);
+    private final String oneDayFromNowString = DateUtil.formatDate(oneDayFromNow);
+    private final String oneDayFromNowIsoString = DateUtil.formatIsoDate(oneDayFromNow);
+    private final LocalDateTime twoDaysFromNow = LocalDateTime.now().plusDays(2);
+    private final String twoDaysFromNowString = DateUtil.formatDate(twoDaysFromNow);
+    private final String twoDaysFromNowIsoString = DateUtil.formatIsoDate(twoDaysFromNow);
+    private final LocalDateTime oneDayToNow = LocalDateTime.now().minusDays(1);
+    private final String oneDayToNowString = DateUtil.formatDate(oneDayToNow);
+    private final String oneDayToNowIsoString = DateUtil.formatIsoDate(oneDayToNow);
+    
+    String commandAdd1 = String.format("add task Buy KOI by \"%s 8pm\"", oneDayToNowString);
+    Task task1 = new Task();
+    String commandAdd2 = String.format("add task Buy Milk by \"%s 9pm\"", oneDayFromNowString);
+    Task task2 = new Task();
+    String commandAdd3 = String.format("add event Some Event from \"%s 4pm\" to \"%s 5pm\"",
+            twoDaysFromNowString, twoDaysFromNowString);
+    Event event3 = new Event();
+    
+    public CompleteUncompleteTaskTest() {
+        task1.setName("Buy KOI");
+        task1.setDueDate(DateUtil.parseDateTime(
+                String.format("%s 20:00:00", oneDayToNowIsoString)));
+        task2.setName("Buy Milk");
+        task2.setDueDate(DateUtil.parseDateTime(
+                String.format("%s 21:00:00", oneDayFromNowIsoString)));
+        event3.setName("Some Event");
+        event3.setStartDate(DateUtil.parseDateTime(
+                String.format("%s 16:00:00", twoDaysFromNowIsoString)));
+        event3.setEndDate(DateUtil.parseDateTime(
+                String.format("%s 17:00:00", twoDaysFromNowIsoString)));
+    }
+    
+    @Before
+    public void fixtures() {
+        console.runCommand("clear");
+        console.runCommand(commandAdd1);
+        console.runCommand(commandAdd2);
+        console.runCommand(commandAdd3);
+    }
+    
+    @Test
+    public void complete_futureTask_show() {
+        assertTaskVisibleAfterCmd("complete 2", task2);
+    }
+    
+    @Test
+    public void complete_overdueTask_hide() {
+        assertTaskNotVisibleAfterCmd("complete 1", task1);
+    }
+    
+    @Test
+    public void uncomplete_futureTask_show() {
+        console.runCommand("complete 2");
+        assertTaskVisibleAfterCmd("uncomplete 2", task2);
+    }
+    
+    @Test
+    public void uncomplete_overdueTask_show() {
+        console.runCommand("complete 1");
+        console.runCommand("list completed");
+        assertTaskVisibleAfterCmd("uncomplete 1", task1);
+    }
+    
+    @Test
+    public void complete_event_error() {
+        console.runCommand("complete 3");
+        String consoleMessage = CompleteTaskController.MESSAGE_CANNOT_COMPLETE_EVENT;
+        assertEquals(consoleMessage, console.getConsoleTextArea());
+    }
+    
+    @Test
+    public void uncomplete_event_error() {
+        console.runCommand("uncomplete 3");
+        String consoleMessage = UncompleteTaskController.MESSAGE_CANNOT_UNCOMPLETE_EVENT;
+        assertEquals(consoleMessage, console.getConsoleTextArea());
+    }
+    
+    @Test
+    public void complete_completedTask_error() {
+        console.runCommand("complete 2");
+        console.runCommand("complete 2");
+        String consoleMessage = CompleteTaskController.MESSAGE_ALREADY_COMPLETED;
+        assertEquals(consoleMessage, console.getConsoleTextArea());
+    }
+    
+    @Test
+    public void uncomplete_uncompleteTask_error() {
+        console.runCommand("uncomplete 1");
+        String consoleMessage = UncompleteTaskController.MESSAGE_ALREADY_INCOMPLETE;
+        assertEquals(consoleMessage, console.getConsoleTextArea());
+    }
+    
+    @Test
+    public void complete_wrongIndex_error() {
+        console.runCommand("complete 10");
+        String consoleMessage = CompleteTaskController.MESSAGE_INVALID_ITEM;
+        assertEquals(consoleMessage, console.getConsoleTextArea());
+    }
+    
+    @Test
+    public void uncomplete_wrongIndex_error() {
+        console.runCommand("uncomplete 10");
+        String consoleMessage = UncompleteTaskController.MESSAGE_INVALID_ITEM;
+        assertEquals(consoleMessage, console.getConsoleTextArea());
+    }
+}