TDD on KaunasPHP result

Test.php

<?php

/**
 * Class Test
 */
class Test extends PHPUnit_Framework_TestCase {

    /**
     * @var Calc
     */
    private $calc;

    protected function setUp()
    {
        $this->calc = new Calc();
    }

    public function test_sums_2_numbers()
    {
        $this->assertSame(2, $this->calc->calculate('1 + 1'));
    }

    public function test_makes_minus_on_2_numbers()
    {
        $this->assertSame(1, $this->calc->calculate('2 - 1'));
    }

    public function test_calc_can_multiply()
    {
        $this->assertEquals(6, $this->calc->calculate('2 * 3'));
    }

    public function test_multiple_operands()
    {
        $this->assertSame(2, $this->calc->calculate('2 + 2 - 2'));
    }

    public function test_operator_position()
    {
        $this->assertSame(6, $this->calc->calculate('2 + 2 * 2'));
    }

}

/**
 * Class Calc
 */
class Calc
{

    /**
     * @param $string
     * @return mixed
     */
    public function calculate($string)
    {

        $result = eval("return $string;");
        return $result;

    }

}

?>