xref: /libcore/harmony-tests/src/test/java/org/apache/harmony/tests/java/util/StackTest.java

/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package org.apache.harmony.tests.java.util;

import java.util.EmptyStackException;
import java.util.Stack;

public class StackTest extends junit.framework.TestCase {

    Stack s;

    /**
     * java.util.Stack#Stack()
     */
    public void test_Constructor() {
        // Test for method java.util.Stack()
        assertEquals("Stack creation failed", 0, s.size());
    }

    /**
     * java.util.Stack#empty()
     */
    public void test_empty() {
        // Test for method boolean java.util.Stack.empty()
        assertTrue("New stack answers non-empty", s.empty());
        s.push("blah");
        assertTrue("Stack should not be empty but answers empty", !s.empty());
        s.pop();
        assertTrue("Stack should be empty but answers non-empty", s.empty());
        s.push(null);
        assertTrue("Stack with null should not be empty but answers empty", !s
                .empty());
    }

    /**
     * java.util.Stack#peek()
     */
    public void test_peek() {
        // Test for method java.lang.Object java.util.Stack.peek()
        String item1 = "Ichi";
        String item2 = "Ni";
        String item3 = "San";
        s.push(item1);
        assertTrue("Peek did not return top item when it was the only item", s
                .peek() == item1);
        s.push(item2);
        s.push(item3);
        assertTrue("Peek did not return top item amoung many other items", s
                .peek() == item3);
        s.pop();
        assertTrue("Peek did not return top item after a pop", s.pop() == item2);
        s.push(null);
        assertNull("Peek did not return top item (wanted: null)",
                s.peek());
        s.pop();
        s.pop();
        try {
            s.pop();
            fail("EmptyStackException expected");
        } catch (EmptyStackException e) {
            //expected
        }
    }

    /**
     * java.util.Stack#pop()
     */
    public void test_pop() {
        // Test for method java.lang.Object java.util.Stack.pop()
        String item1 = "Ichi";
        String item2 = "Ni";
        Object lastPopped;
        s.push(item1);
        s.push(item2);

        try {
            lastPopped = s.pop();
            assertTrue("a) Pop did not return top item", lastPopped == item2);
        } catch (EmptyStackException e) {
            fail(
                    "a) Pop threw EmptyStackException when stack should not have been empty");
        }

        try {
            lastPopped = s.pop();
            assertTrue("b) Pop did not return top item", lastPopped == item1);
        } catch (EmptyStackException e) {
            fail(
                    "b) Pop threw EmptyStackException when stack should not have been empty");
        }

        s.push(null);
        try {
            lastPopped = s.pop();
            assertNull("c) Pop did not return top item", lastPopped);
        } catch (EmptyStackException e) {
            fail(
                    "c) Pop threw EmptyStackException when stack should not have been empty");
        }

        try {
            lastPopped = s.pop();
            fail(
                    "d) Pop did not throw EmptyStackException when stack should have been empty");
        } catch (EmptyStackException e) {
            return;
        }

    }

    /**
     * java.util.Stack#push(java.lang.Object)
     */
    public void test_pushLjava_lang_Object() {
        Object [] array = {new Integer(0), new Object(),
                           new Float(0), new String()};

        Stack<Object> stack = new Stack<Object>();
        for(int i = 0; i < array.length; i++) {
            stack.push(array[i]);
        }
        for(int i = 0; i < array.length; i++) {
            assertEquals(array.length - i, stack.search(array[i]));
        }
    }

    /**
     * java.util.Stack#search(java.lang.Object)
     */
    public void test_searchLjava_lang_Object() {
        // Test for method int java.util.Stack.search(java.lang.Object)
        String item1 = "Ichi";
        String item2 = "Ni";
        String item3 = "San";
        s.push(item1);
        s.push(item2);
        s.push(item3);
        assertEquals("Search returned incorrect value for equivalent object", 3, s
                .search(item1));
        assertEquals("Search returned incorrect value for equal object", 3, s
                .search("Ichi"));
        s.pop();
        assertEquals("Search returned incorrect value for equivalent object at top of stack",
                1, s.search(item2));
        assertEquals("Search returned incorrect value for equal object at top of stack",
                1, s.search("Ni"));
        s.push(null);
        assertEquals("Search returned incorrect value for search for null at top of stack",
                1, s.search(null));
        s.push("Shi");
        assertEquals("Search returned incorrect value for search for null", 2, s
                .search(null));
        s.pop();
        s.pop();
        assertEquals("Search returned incorrect value for search for null--wanted -1",
                -1, s.search(null));
    }

    static class BugStack<E> extends Stack<E> {
        public void setLength(int elementCount) {
            this.elementCount = elementCount;
        }

        public int getLength() {
            return elementCount;
        }
    }

    //test for wrong exception threw by pop method
    public void test_pop_modify_elementCount() {
        BugStack<String> testStack = new BugStack<String>();
        testStack.push("A");
        testStack.push("B");
        testStack.setLength(20);
        try {
            testStack.pop();
            fail("Should throw ArrayIndexOutOfBoundsException here");
        } catch (ArrayIndexOutOfBoundsException e) {
            //Expected to throw ArrayIndexOutOfBoundsException here
        } catch (EmptyStackException e) {
            fail("Should throw ArrayIndexOutOfBoundsException here");
        }
    }

    /**
     * Sets up the fixture, for example, open a network connection. This method
     * is called before a test is executed.
     */
    protected void setUp() {
        s = new Stack();
    }

    /**
     * Tears down the fixture, for example, close a network connection. This
     * method is called after a test is executed.
     */
    protected void tearDown() {
    }
}