public function testDecrement()
{
$key = __FUNCTION__;
$result = $this->File->write(array($key => 5));
$this->assertTrue($result);
$expected = 4;
$result = $this->File->decrement($key);
$this->assertEqual($expected, $result);
$expected = array($key => 4);
$result = $this->File->read(array($key));
$this->assertEqual($expected, $result);
}