ArbitrarilyNestedArraysTest

package com.yusufaytas.test.intercom;

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

import org.junit.Test;

import static org.junit.Assert.*;

public class ArbitrarilyNestedArraysTest {

	@Test
	public void testflattenWithZeroElement() {
		List<Object> arrays = createArbitraryList(new int[]{}, 0, 0);
		List<Integer> actualArray = new ArbitrarilyNestedArrays().flatten(arrays);
		assertEquals(0, actualArray.size());
	}

	@Test
	public void testflattenWithElements() {
		int[] expectedElements = { 1, 2, 3 , 4, 5};
		for (int i = 0; i < expectedElements.length; i++) {
			List<Object> arrays = createArbitraryList(expectedElements, 0, expectedElements.length);
			List<Integer> actualArray = new ArbitrarilyNestedArrays().flatten(arrays);
			for (int j = 0; j < expectedElements.length; j++) {
				assertEquals(expectedElements[j], (int) actualArray.get(j));
			}
		}
	}

	public List<Object> createArbitraryList(int[] elements, int begin, int end) {
		List<Object> list = new ArrayList<Object>();
		while (begin < end) {
			int tempEnd = (int) (Math.random() * (end - begin + 1)) + begin;
			if (Math.random() > 0.5) {
				for (int i = begin; i < tempEnd; i++) {
					list.add(elements[i]);
				}
			} else {
				List<Object> subList = createArbitraryList(elements, begin, tempEnd);
				list.add(subList);
			}
			begin = tempEnd;
		}
		return list;
	}
}