public void ShouldAllowTestingForNotNullWithMessage()
{
//GIVEN
var levels = new Level1();
//THEN
var e = Assert.Throws <AssertionException>(() =>
levels.AssertNotNull("l1")
._l2.AssertNotNull("l2")
._l3.AssertNotNull("l3")
._l4.AssertNotNull("l4")
._l5.AssertNotNull("l5")
);
StringAssert.Contains("l5", e.Message);
}