Strange Failing Travis CI Test

gistfile1.aw

<?php

    /**
     * The method that is being tested
     */
    public function generateKeyNumber($key) {
        // If there are no spaces, reject
        if (0 === substr_count($key, ' ')) {
            return '';
        }

        $int = (int)preg_replace('[\D]', '', $key) / substr_count($key, ' ');

        return (is_int($int)) ? $int : '';
    }

/*****/

    /**
     * The unit test
     * @dataProvider KeyProvider
     */
    public function testKeySigningForHandshake($accept, $key) {
        $this->assertEquals($accept, $this->_version->generateKeyNumber($key));
    }

    public static function KeyProvider() {
        return array(
            array(179922739, '17  9 G`ZD9   2 2b 7X 3 /r90')
          , array('', '17  9 G`ZD9   2 2b 7X 3 /r91')

            // This test fails on Travis CI, with exact same environment as two other tested, passing envs
          , array(906585445, '3e6b263  4 17 80')

          , array('', '3e6b263 4 17 80')
          , array('', '3e6b63 4 17 80')
          , array('', '3e6b6341780')
        );
    }