(should contain) as argument to list.iter about fsunit

[sergey-tihon]

Expression 2

If you remove pipe operator from your second expression

list2 |> Seq.iter (fun x -> list1 |> should contain x)

you will get

list2 |> Seq.iter (fun x -> should contain x list1)

Expression 1

In the same time, if you add param to the function from first expression

list2 |> Seq.iter (list1 |> (should contain) )

you will get

list2 |> Seq.iter (fun x -> (list1 |> (should contain)) x)

that is equal to

list2 |> Seq.iter (fun x -> (should contain list1) x)

that is equal to

list2 |> Seq.iter (fun x -> should contain list1 x)

Conclusion

Now it should be obvious that they are two different expressions:

list2 |> Seq.iter (fun x -> should contain list1 x)
list2 |> Seq.iter (fun x -> should contain x list1)