Count with predicate

[jnyrup]

When using the Count method with a predicate overload the predicate is not taken into account.

list.Count(e => e > 1).Should().Be(2);

is simplified into:

list.Should().HaveCount(2);

[Meir017]

should this case be ignored?

there is an overload HaveCount(Expression<Func<int, bool>> countPredicate, string because = "", params object[] becauseArgs) but I'm not sure how to use it.
@dennisdoomen is it possible to write the assertion using this overload?

[jnyrup]

If you're updating the docs, there is a related example in there:

- old: |
    actual.Where(x => x.SomeProperty).Should().HaveCount(1);
  new: |
    actual.Should().ContainSingle(x => x.SomeProperty);

https://github.com/fluentassertions/fluentassertions/blob/88c4fd6ff7c5444b46096553ea7bd2e3df804289/docs/_data/tips/collections.yml#L248

And I would probably replace

list.Count(e => e > 1).Should().Be(2);

with

list.Where(e => e > 1).Should().HaveCount(2);

[dennisdoomen]

When using the Count method with a predicate overload the predicate is not taken into account.

What do you mean with that? The Count is an LINQ extension method. The resulting IEnumerable<T> should return a lazy evaluated filter.

[Meir017]

@dennisdoomen he was talking about the analyzer...

I meant that I wanted to see if it was possible to rewrite the assertion using that overload

[jnyrup]

@dennisdoomen
The "not taken in to account" is my attempt to blame the computer rather than @Meir017's great work.

When using The Count method from LINQ that takes an predicate, the simplified assertion produced by the analyzer no longer contains the predicate.