package guitests;

import static org.junit.Assert.assertTrue;

import org.junit.Test;

public class ClearCommandTest extends TaskManagerGuiTest {

    // @@author A0141102H
    @Test
    public void clear() {

        // verify a non-empty list can be cleared
        assertTrue(taskListPanel.isListMatching(td.getTypicalTasks()));
        assertClearCommandSuccess();

        // verify other commands can work after a clear command
        commandBox.runCommand(td.sampleEvent.getAddCommand());
        assertTrue(eventTaskListPanel.isListMatching(td.sampleEvent));
        commandBox.runCommand("DELETE 1");
        assertListSize(0);

        // verify clear command works when the list is empty
        assertClearCommandSuccess();
    }

    private void assertClearCommandSuccess() {
        commandBox.runCommand("CLEAR");
        assertListSize(0);
        assertResultMessage("Task Manager has been cleared!");
    }
}

package guitests;

import static org.junit.Assert.assertTrue;

import org.junit.Test;

public class ClearCommandTest extends TaskManagerGuiTest {

    // @@author A0141102H
    @Test
    public void clear() {

        // verify a non-empty list can be cleared
        assertTrue(eventTaskListPanel.isListMatching(td.getTypicalTasks()));
        assertTrue(deadlineTaskListPanel.isListMatching(td.getTypicalTasks()));
        assertTrue(floatingTaskListPanel.isListMatching(td.getTypicalTasks()));
        assertClearCommandSuccess();

        // verify other commands can work after a clear command
        commandBox.runCommand(td.sampleEvent.getAddCommand());
        assertTrue(eventTaskListPanel.isListMatching(td.sampleEvent));
        commandBox.runCommand("DELETE 1");
        assertListSize(0);

        // verify clear command works when the list is empty
        assertClearCommandSuccess();
    }

    private void assertClearCommandSuccess() {
        commandBox.runCommand("CLEAR");
        assertListSize(0);
        assertResultMessage("Task Manager has been cleared!");
    }
}

Update Clear command test