Nerdery PHP Challenge Yourselph - 017 An Array Problem

array_combine_keys.php

<?php
/**
 * Challenge Yourselph - 017
 *
 * An Array Problem
 *
 * I have an array of values, keyed by numerical index. What I want is an associative array of those same values, but keyed by corresponding value.
 *
 * Test It: vendor/bin/phpunit ArrayCombineKeysTest.php
 *
 * @author Konr Ness <konr.ness@gmail.com>
 */

/**
 * Creates an array by using the input array's values for its key/values pairs
 *
 * @param array $array
 * @return array
 */
function array_combine_keys(array $array) {
    return array_combine($array, $array);
}

ArrayCombineKeysTest.php

<?php

require_once 'array_combine_keys.php';

class ArrayCombineKeysTest extends PHPUnit_Framework_TestCase
{
    public function testExample()
    {
        $input          = array('apples', 'oranges', 'bananas');
        $expectedOutput = array('apples' => 'apples', 'oranges' => 'oranges', 'bananas' => 'bananas');

        $actualOutput = array_combine_keys($input);

        $this->assertEquals($expectedOutput, $actualOutput);
    }

    public function testDuplicateKeys()
    {
        $input          = array('apples', 'oranges', 'bananas', 'apples');
        $expectedOutput = array('apples' => 'apples', 'oranges' => 'oranges', 'bananas' => 'bananas');

        $actualOutput = array_combine_keys($input);

        $this->assertEquals($expectedOutput, $actualOutput);
    }

    public function testNumericValues()
    {
        $input          = array(2, 3, 4);
        $expectedOutput = array(2 => 2, 3 => 3, 4 => 4);

        $actualOutput = array_combine_keys($input);

        $this->assertEquals($expectedOutput, $actualOutput);
    }

    public function testEmptyArrayInput()
    {
        $input          = array();
        $expectedOutput = array();

        $actualOutput = array_combine_keys($input);

        $this->assertEquals($expectedOutput, $actualOutput);
    }

    /**
     * @expectedException PHPUnit_Framework_Error
     */
    public function testZeroArguments()
    {
        array_combine_keys();
    }

    /**
     * @expectedException PHPUnit_Framework_Error
     */
    public function testScalarArgument()
    {
        array_combine_keys(42);
    }

    /**
     * @expectedException PHPUnit_Framework_Error
     */
    public function testStringArgument()
    {
        array_combine_keys("foo");
    }

}
 

composer.json

{
    "name": "kness/issue15",
    "authors": [
        {
            "name": "Konr Ness",
            "email": "kness@nerdery.com"
        }
    ],
    "require-dev": {
        "phpunit/phpunit" : "*"
    }
}