Assert collection .All().Satisfy(...) does not work as expected

[PonasJustas]

Sample code does not work:
https://tunit.dev/docs/assertions/collections/#with-satisfy

[Test]
public async Task All_Satisfy()
{
    var users = new[]
    {
        new User { Name = "Alice", Age = 25 },
        new User { Name = "Bob", Age = 30 }
    };

    await Assert.That(users)
        .All()
        .Satisfy(u => Assert.That(u.Age).IsGreaterThan(18));
}

[sliekens]

Yep, same in my project, something weird is happening with the callback signature of Satisfy where the type of the argument is both User and IAssertionSource<User>. Never seen something like this before. @thomhurst did you accidentally invent union types in C#?

[thomhurst]

Sorry just updated the docs for this. Satisfy works like:

[Test]
public async Task All_Satisfy()
{
    var users = new[]
    {
        new User { Name = "Alice", Age = 25 },
        new User { Name = "Bob", Age = 30 }
    };

    await Assert.That(users)
        .All()
-        .Satisfy(u => Assert.That(u.Age).IsGreaterThan(18));
+        .Satisfy(u => u.Age, age => age.IsGreaterThan(18));
}

[sliekens]

@thomhurst isn't that essentially the same as the example below it?

You can also map to any expression:

[Test]
public async Task All_Satisfy_With_Mapper()
{
    var users = new[]
    {
        new User { Name = "Alice", Age = 25 },
        new User { Name = "Bob", Age = 30 }
    };

    await Assert.That(users)
        .All()
        .Satisfy(
            u => u.Name,
            name => name.IsNotEmpty()
        );
}

(From https://tunit.dev/docs/assertions/collections#with-satisfy)

I was under the impression that both syntaxes were valid

• await Assert.That(users).All().Satisfy(user => Assert.That(user.Name).IsNotEmpty());
• await Assert.That(users).All().Satisfy(u => u.Name, name => name.IsNotEmpty());

[thomhurst]

When you have an IEnumerable<T> - The single lambda assertion will be for IAssertionSource<T>

When you use the two parameter overload with the mapper, it'll be for whatever type you mapped to i.e. IAssertionSource<TMapped>

await Assert.That(numbers).All().Satisfy(n => n.IsGreaterThan(1));

await Assert.That(users).All().Satisfy(user => user.IsNotNull());
await Assert.That(users).All().Satisfy(u => u.Name, name => name.IsNotEmpty());

[sliekens]

Ok I understand better what is happening, vscode does something very weird where it combines the overloads of Satisfy, combining properties of IAssertionSource<TItem> and TItem into a single list.

(I still think the docs now has two examples that show the same thing @ https://tunit.dev/docs/assertions/collections#with-satisfy)

[thomhurst]

I've updated the docs again. Sorry for the confusion!