IsEquivalent with default CollectionOrdering does not print expected sequence

[quellatalo]

It seems that without specifying CollectionOrdering, IsEquivalent would use the Matching option.
However, it does not print the expected sequence when it fails.

For example:

    [Test]
    [Arguments(new[] { 1, 2, 3 }, new[] { 3, 2, 1 }, CollectionOrdering.Matching)] // case 0
    [Arguments(new[] { 1, 2, 3 }, new[] { 1, 2, 3, 4 }, CollectionOrdering.Any)] // case 1
    [Arguments(new[] { 1, 2, 3 }, new[] { 3, 2, 1 })] // case 2
    [Arguments(new[] { 1, 2, 3 }, new[] { 1, 2, 3, 4 })] // case 3
    public async Task IsEquivalent_Fail(int[] a, int[] b, CollectionOrdering? collectionOrdering = null)
        => await (collectionOrdering is null
            ? Assert.That(a).IsEquivalentTo(b)
            : Assert.That(a).IsEquivalentTo(b, collectionOrdering.Value));

case 0 starts with: AssertionException: Expected a to be equivalent to [3, 2, 1]
case 1 starts with: AssertionException: Expected a to be equivalent to [1, 2, 3, 4]
However, case 2 and 3 start with: AssertionException: Expected a to be equivalent to b

[quellatalo]

Also, IsNotEquivalentTo doesn't accept CollectionOrdering, and it always use SequenceEqual to check. (same as CollectionOrdering.Matching)

I see in TUnit you have the same condition split into 2: positive & negative and are maintaining both (Is__ and IsNot__).
I think it's quite hard to maintain.
Is it not possible to separate the Not? For example, something like this would be nice:

await Assert.That(actualCollection).Is.EquivalentTo(expectedCollection, CollectionOrdering.Any);
await Assert.That(actualCollection).Is.Not.EquivalentTo(expectedCollection, CollectionOrdering.Matching);

It would be quite a big change though.

[thomhurst]

Assertions were originally like that but the community did not like it