我正在做一个单元测试,测试我的连接字符串。这是我的测试方法中的代码:
 [TestMethod()]
    public void connectionStringTest()
    {
        //string expected = null; // TODO: Initialize to an appropriate value
        string actual;
        string expected = " User Id=ownitsbio;Password=ownitsbio;Data Source=preprod";
        actual = ConfigurationManager.ConnectionStrings["ownitsbio"].ConnectionString;
        Assert.AreEqual(expected, actual);
        //Assert.Inconclusive(expected);
    }
我得到这个错误System.NullReferenceException: Object reference not set to an instance of an object。可能是什么问题呢??请帮忙!