JustDummies

xUnit collects BeforeAfterTestAttributes from the test method, its declaring class and the assembly — nowhere else. [Reproducible] on a helper method, on an arrange method, or on a method whose [Fact] was removed during a refactor, is never read: it pins no seed and reports none.

What makes this worth a diagnostic is that a working [Reproducible] is silent by design — a passing test reports nothing. The inert form and the working form are therefore indistinguishable from the outside, right up until a failure that should have named a seed does not.

Remove it, or move it to the level xUnit actually reads.

Noncompliant

public class OrderTests {
    [Reproducible]                                   // JD010: never read — this is not a test
    private string ArrangeReference() => Any.String().StartingWith("ORD-").Generate();

    [Fact]
    public void It_is_accepted() { /* uses ArrangeReference() */ }
}

Compliant

[Reproducible]                                       // the class level covers every test it declares
public class OrderTests {
    private string ArrangeReference() => Any.String().StartingWith("ORD-").Generate();

    [Fact]
    public void It_is_accepted() { /* ... */ }
}

What it does not flag

• The attribute on a [Fact], a [Theory], or any third-party attribute implementing xUnit’s IFactAttribute — the rule keys on that interface, not on a fixed list.
• The attribute on a class or on the assembly, which are exactly the levels xUnit does collect.