CollectionShouldNotContainProperty is too aggresive

[jnyrup]

Description

The CollectionShouldNotContainProperty is triggered when the assertions already seems idiomatic.

An example is when the expression inside OnlyContain contains no negations.

var list = new[] { "" };

list.Should().OnlyContain(e => e.Contains(""));

Expected behavior:

The analyzer should not be triggered, as the assertion is already idiomatic.

Actual behavior:

The analyzer is triggered.

Versions

Fluent Assertions Analyzers 0.11.2
.NET Framework 4.6.1

[Meir017]

@jnyrup since the case of a Should followed by OnlyContain does'n currently have a codefix maybe I should just ignore this case for now untill I fix #2

In this case the CodeFix should be

list.Should().NotContain(e => !e.Contains(""));

which seems fair

[jnyrup]

Maybe I was too quick on this one.
I personally prefer OnlyContain(e => e.MyBooleanProperty) over NotContain(e => !e.MyBooleanProperty) and that's the example in https://fluentassertions.com/tips#Collections-22.

But if someone prefers it the other way around, it is of course beneficial to have a tools to do the transforms.
For many of its refactorings, Roslynator has methods for transforming in both directions, but has one disabled by default.
E.g.
https://github.com/JosefPihrt/Roslynator/blob/master/docs/refactorings/RR0168.md
and
https://github.com/JosefPihrt/Roslynator/blob/master/docs/refactorings/RR0171.md