@NullUnmarked
public class TearDownStackTest extends TestCase {

  private final TearDownStack tearDownStack = new TearDownStack();

  public void testSingleTearDown() throws Exception {
    TearDownStack stack = buildTearDownStack();

    SimpleTearDown tearDown = new SimpleTearDown();
    stack.addTearDown(tearDown);

    assertEquals(false, tearDown.ran);

    stack.runTearDown();

@NullUnmarked
public class TearDownStackTest extends TestCase {

  private final TearDownStack tearDownStack = new TearDownStack();

  public void testSingleTearDown() throws Exception {
    TearDownStack stack = buildTearDownStack();

    SimpleTearDown tearDown = new SimpleTearDown();
    stack.addTearDown(tearDown);

    assertEquals(false, tearDown.ran);

    stack.runTearDown();