PushTag tag = new PushTag();
stack.setValue("foo", "bar");
tag.setPageContext(pageContext);
tag.setValue("foo");
try {
assertEquals(2, stack.size());
tag.doStartTag();
assertEquals(3, stack.size());
tag.doEndTag();
assertEquals(2, stack.size());
} catch (JspException e) {
e.printStackTrace();
fail();
}