ShouldBe() is overly permissive in null propagation scenarios

[blake-costar]

When NULL propagates down to a property value via the propagation operator ?. shouldly seems to glibly agree to almost any assertion. I don't think the following test should pass:

    [TestClass]
    public class UnitTest1
    {
        [TestMethod]
        public void TestMethod1()
        {
            //Act:
            Person p = null;
            //Assert:
            p?.BirthDate.ShouldBe(DateTimeOffset.Now);
        }
    }
    
    public class Person
    {
        public DateTimeOffset? BirthDate { get; set; }
    }

[afroze9]

The above code translates into:

        [TestMethod]
        public void TestMethod1()
        {
            //Act:
            Person p = null;

            //Assert:
            if(p != null)
            {
                p.BirthDate.ShouldBe(DateTimeOffset.Now);
            }
        }

The code is not even reaching the assert statement. I'm not sure if it even would be possible to handle this scenario.

[Stuart Lang]

That's correct, we'd need to implement an analyzer package to detect and warn when mixing this usage with Shouldly assertions.

[Simon Schulze]

Bit late but i have just come across this and there seem to be a very simple fix for the problem:
Just wrap the null-propagated terms in round brackets:

(p?.BirthDate).ShouldBe(DateTimeOffster.Now);

[Joseph Musser]

Also consider p.ShouldNotBeNull().BirthDaty.ShouldBe(...);

Duplicate of #710.