//@@author A0142255M
package guitests;

import static seedu.tache.commons.core.Messages.MESSAGE_INVALID_COMMAND_FORMAT;

import org.junit.Test;

import seedu.tache.commons.core.Messages;
import seedu.tache.logic.commands.HelpCommand;

public class ResultDisplayTest extends TaskManagerGuiTest {

    @Test
    public void resultDisplay_blankOnStartup_success() {
        assertResultMessage("");
    }

    @Test
    public void resultDisplay_unknownCommand_failure() {
        commandBox.runCommand("yutyfcydvchui");
        assertResultMessage(Messages.MESSAGE_UNKNOWN_COMMAND);

        commandBox.runCommand("");
        assertResultMessage(String.format(MESSAGE_INVALID_COMMAND_FORMAT, HelpCommand.MESSAGE_USAGE));
    }

}

//@@author A0142255M
package guitests;

import org.junit.Test;

import seedu.tache.commons.core.Messages;

public class ResultDisplayTest extends TaskManagerGuiTest {

    @Test
    public void resultDisplay_blankOnStartup_success() {
        assertResultMessage("");
    }

    @Test
    public void resultDisplay_unknownCommand_failure() {
        commandBox.runCommand("yutyfcydvchui");
        assertResultMessage(Messages.MESSAGE_UNKNOWN_COMMAND);

        commandBox.runCommand("");
        assertResultMessage(Messages.MESSAGE_INVALID_COMMAND_FORMAT);
    }

}

--- 
+++ 
@@ -1,9 +1,12 @@
 //@@author A0142255M
 package guitests;
+
+import static seedu.tache.commons.core.Messages.MESSAGE_INVALID_COMMAND_FORMAT;
 
 import org.junit.Test;
 
 import seedu.tache.commons.core.Messages;
+import seedu.tache.logic.commands.HelpCommand;
 
 public class ResultDisplayTest extends TaskManagerGuiTest {
 
@@ -18,7 +21,7 @@
         assertResultMessage(Messages.MESSAGE_UNKNOWN_COMMAND);
 
         commandBox.runCommand("");
-        assertResultMessage(Messages.MESSAGE_INVALID_COMMAND_FORMAT);
+        assertResultMessage(String.format(MESSAGE_INVALID_COMMAND_FORMAT, HelpCommand.MESSAGE_USAGE));
     }
 
 }
Fix JUnit result display test
