For beginners it might not be obvious why a simple myEntityCollection.Should().NotContain(entity) executes SQL queries and (for bigger tables) takes forever due to the N+1 query problem.

The problem is that the DefaultValueFormatter tries to build an output string over many nesting levels of public properties in case ToString() is not overloaded (the default case for generated entites in Linq2Sql and afaik also for EntityFramework).

It would probably be best to always use ToString() and to enforce that the user explicitly must enable the DefaultValueFormatter's Public-Property-Via-Reflection-ToString behavior.

What are your thoughts on this issue?

BR, D.R.