public void testsAddingElementsToStack() {
ss.push("1");
assertEquals("1", ss.peek());
ss.push("2");
assertEquals("2", ss.peek());
ss.push("3");
assertEquals("3", ss.peek());
}
@Test
public void testsLookingAtTopElement() {
assertEquals(null, ss.peek());
ss.push("1");
assertEquals(ss.peek(), "1");
assertTrue(ss.isEmpty() == false);
ss.push("2");
assertEquals(ss.peek(), "2");
ss.push("3");
assertEquals(ss.peek(), "3");
}
@Test
public void testsRemovingAnElementFromStack() {
ss.push("1");
ss.push("2");
ss.push("3");
assertTrue(ss.isEmpty() == false);
assertEquals("3", ss.pop());
assertEquals("2", ss.peek());
assertEquals("2", ss.pop());
assertEquals("1", ss.peek());
assertEquals("1", ss.pop());
assertEquals(null, ss.peek());
assertTrue(ss.isEmpty() == true);
assertEquals(null, ss.pop());
}
@Test
public void pushTwoStringsThenPopOne() {
ss.push("Jim");
ss.push("Tim");
assertEquals(ss.pop(), "Tim");
assertEquals(ss.peek(), "Jim");
}
@Test
public void pushThreeStringsThenPeekTop() {
ss.push("Jim");
ss.push("Tim");
ss.push("Ben");
assertEquals("Ben", ss.peek());
}
@Test
public void pushOneStringThenPopOne() {
ss.push("Jim");
assertFalse(ss.isEmpty());
assertEquals(ss.pop(), "Jim");
assertNull(ss.peek());
assertTrue(ss.isEmpty());
}
@Test
public void peekAnEmptyStack() {
assertNull(ss.peek());
}
@Test
public void pushOneStringThenPeek() {
ss.push("1");
assertEquals("1", ss.peek());
}