@Test
public void testIsMepty() {
CustomStack<String> customStack = new CustomStack<String>();
assertTrue(customStack.empty());
customStack.push("element1");
assertFalse(customStack.empty());
customStack.pop();
assertTrue(customStack.empty());
}
@Test
public void testPushPop() {
String el0 = "firstElement0";
String el1 = "firstElement1";
String el2 = "firstElement2";
String el3 = "firstElement3";
CustomStack<String> customStack = new CustomStack<String>();
customStack.push(el0);
assertSame(el0, customStack.pop());
customStack.push(el0);
customStack.push(el0);
assertSame(el0, customStack.pop());
customStack.push(el1);
customStack.push(el2);
customStack.push(el3);
customStack.push(el1);
assertSame(el1, customStack.pop());
assertSame(el3, customStack.pop());
assertSame(el2, customStack.pop());
assertSame(el1, customStack.pop());
assertSame(el0, customStack.pop());
assertTrue(customStack.empty());
}