public function diviser($a, $b)
    {
		if (0 == $b) {
			throw new UnexpectedValueException;
		}

		return $a / $b;
    }
------------------------------------------------------------------------
    public function testDiviserDiviseurZero()
    {
	    $this->setExpectedException('UnexpectedValueException');
         $this->calculateur->diviser(10,0);
    }
------------------------------------------------------------------------
    public function testDiviserNormal()
    {
        $this->assertEquals(2, $this->calculateur->diviser(20, 10));
    }
------------------------------------------------------------------------
    public function testDiviserDividendeNegatif()
    {
        $this->assertEquals(-2, $this->calculateur->diviser(-20, 10));
    }
------------------------------------------------------------------------
    public function testDiviserDividendeNegatifAleatoire()
    {
        $this->assertLessThan(0, $this->calculateur->diviser(mt_rand(-10, -1), 10));
    }
------------------------------------------------------------------------
   public function testDiviserDiviseurNegatif()
    {
        $this->assertEquals(-2, $this->calculateur->diviser(20, -10));
    }
------------------------------------------------------------------------