Gaufrette\Adapter\InMemory::exists PHP Method

    public function exists($key)
    {
        return array_key_exists($key, $this->files);
    }

 public function testWriteAndRead()
 {
     $adapter = new InMemory();
     $this->assertFalse($adapter->exists('foobar'));
     $adapter->write('foobar', 'Some content');
     $this->assertTrue($adapter->exists('foobar'));
     $this->assertEquals('Some content', $adapter->read('foobar'));
 }