package edu.brown.cs.systems.tracingplane.transit_layer.impl;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertTrue;
import org.junit.Test;
import edu.brown.cs.systems.tracingplane.transit_layer.Baggage;

public class TestDefaultTransitLayer {

    @Test
    public void testNullTransitLayerImpl() {
        assertNotNull(Baggage.transit);
        assertTrue(Baggage.transit instanceof NullTransitLayer);

        Baggage baggage = Baggage.newInstance();
        assertNotNull(baggage);
        assertEquals(baggage, NullBaggage.INSTANCE);
    }

}

package edu.brown.cs.systems.tracingplane.transit_layer.impl;

import org.junit.Test;
import edu.brown.cs.systems.tracingplane.transit_layer.Baggage;
import junit.framework.TestCase;

public class TestDefaultTransitLayer extends TestCase {

    @Test
    public void testNullTransitLayerImpl() {
        assertNotNull(Baggage.transit);
        assertTrue(Baggage.transit instanceof NullTransitLayer);

        Baggage baggage = Baggage.newInstance();
        assertNotNull(baggage);
        assertEquals(baggage, NullBaggage.INSTANCE);
    }

}

--- 
+++ 
@@ -1,10 +1,12 @@
 package edu.brown.cs.systems.tracingplane.transit_layer.impl;
 
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
 import org.junit.Test;
 import edu.brown.cs.systems.tracingplane.transit_layer.Baggage;
-import junit.framework.TestCase;
 
-public class TestDefaultTransitLayer extends TestCase {
+public class TestDefaultTransitLayer {
 
     @Test
     public void testNullTransitLayerImpl() {
Convert transit-layer testcases to JUnit 4
