public void When_ConnectionStringIsPassed_SetConnectionString_Should_UpdateConfigXml()
{
LoadWebConfigAsXmlDocument();
var expected = new KeyValuePair <string, string>("BP_ConnectionStrings_Key1", "TestValue");
//Action writer = () => { _writer.SetAppSetting(key, value); };
//writer.Should().Throw<ArgumentNullException>();
_writer.SetConnectionString(expected.Key, expected.Value);
var actual = _writer.GetConnectionString(expected.Key);
actual.Should().NotBeNullOrEmpty();
expected.Value.Should().BeEquivalentTo(actual);
}