public void 初始化一個SafeCollection並加入1個元素_加入成功_集合中應包含該元素且長度為1()
{
var safeCollection = new SafeCollection <int>();
var fixture = new Fixture();
var element = fixture.Create <int>();
safeCollection.Add(element);
const int expecetedCount = 1;
safeCollection.First().Should().Be(element);
safeCollection.Count.Should().Be(expecetedCount);
}