dcevm/dcevm/src/test/java7/com/github/dcevm/test/fields/YieldTest.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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package com.github.dcevm.test.fields;

import org.junit.Before;
import org.junit.Test;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import static com.github.dcevm.test.util.HotSwapTestHelper.__toVersion__;
import static com.github.dcevm.test.util.HotSwapTestHelper.__version__;
import static org.junit.Assert.assertEquals;

/**
 * Test case that produces a list of integer values recursively.
 * The recursive function does not contain a conditional statement.
 * The recursion is stopped by swapping the recursive method with a different non-recursive implementation.
 *
 * @author Thomas Wuerthinger
 */
public class YieldTest {

    // Version 0
    public static class Base {

        protected List<Integer> arr = new ArrayList<Integer>();

        public void reset() {
            __toVersion__(0);
        }

        public void next() {
            __toVersion__(__version__() + 1);
        }
    }

    public static abstract class A extends Base {

        public List<Integer> gen() {
            arr.add(produce());
            next();
            return gen();
        }

        public abstract int produce();
    }

    public static class B extends A {

        @Override
        public int produce() {
            return 1;
        }
    }

    public static class B___10 extends A {

        @Override
        public int produce() {
            return 2;
        }
    }

    public static class B___20 extends A {

        private int x;

        @Override
        public int produce() {
            return ++x;
        }
    }

    public static class A___30 extends Base {

        public List<Integer> gen() {
            reset();
            return arr;
        }
    }

    @Before
    public void setUp() throws Exception {
        __toVersion__(0);
    }

    @Test
    public void testYield() {

        assert __version__() == 0;

        B b = new B();
        assertEquals(Arrays.asList(
                1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
                2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
                1, 2, 3, 4, 5, 6, 7, 8, 9, 10), b.gen());
        assert __version__() == 0;
    }
}