RocketLogicTest

package com;

import org.junit.Assert;
import org.junit.Test;

public class RocketLogicTest {

    Integer[] expectedArray = new Integer[]{1, 3, 5, 7, 9, 2, 4, 6, 8, 10};

    @Test
    public void testNullInput() throws IllegalArgumentException {
        Assert.assertNull(
                "Passing a null array returning null",
                NestedArrayFlattener.flatten(null)
        );
    }

    @Test
    public void testEmptyArray() throws IllegalArgumentException {
        Assert.assertArrayEquals(
                "Passing empty array return the empty array",
                new Integer[]{},
                NestedArrayFlattener.flatten(new Object[]{})
        );
    }

    @Test
    public void testFlatArray() throws IllegalArgumentException {
        Assert.assertArrayEquals(
                "Flat array being passed, return the same array as that's already flattened",
                expectedArray,
                NestedArrayFlattener.flatten(new Object[]{1, 3, 5, 7, 9, 2, 4, 6, 8, 10})
        );
    }

    @Test(expected = IllegalArgumentException.class)
    public void throwsExceptionForObjectInArray() throws IllegalArgumentException {
    	NestedArrayFlattener.flatten(
                new Object[]{new Object()}
        );
    }

    @Test
    public void testNestedArray() throws IllegalArgumentException {
        Assert.assertArrayEquals(
                "Nested array test with single nesting",
                expectedArray,
                NestedArrayFlattener.flatten(new Object[]{7, 1, 9, 13, new Object[]{23, 6, 24, 8}, 19, 100})
        );
    }

    @Test(expected = IllegalArgumentException.class)
    public void throwsExceptionForNullInNestedArray() throws IllegalArgumentException {
    	NestedArrayFlattener.flatten(
                new Object[]{1, 2, new Object[]{3, null}}
        );
    }

    @Test
    public void testMultipleNestedArrays() throws IllegalArgumentException {
        Assert.assertArrayEquals(
                "Nested array test with multiple nestings",
                expectedArray,
                NestedArrayFlattener.flatten(new Object[]{1, new Object[]{3, 4, new Object[]{5}, 6, 7}, 2, 8, 9, 10})
        );
    }

    @Test(expected = IllegalArgumentException.class)
    public void throwsExceptionForObjectInNestedArray() throws IllegalArgumentException {
    	NestedArrayFlattener.flatten(
                new Object[]{1, 2, new Object[]{3, new Object()}}
        );
    }

    @Test(expected = IllegalArgumentException.class)
    public void throwsExceptionForNullInArray() throws IllegalArgumentException {
    	NestedArrayFlattener.flatten(
                new Object[]{null}
        );
    }
}