v2 v3   Error

xUnit9014

"MemberData parameter cannot use params modifier"

Cause

A violation of this rule occurs when a parameter of a [MemberData] method uses the params modifier.

Reason for rule

When using the reflection-based version of xUnit.net, it will attempt to examine your [MemberData] arguments values at runtime and dynamically construct the params array on your behalf. This requires reflection features that are not available in Native AOT.

How to fix violations

To fix a violation of this rule, remove the params modifier on the parameter, and update the [MemberData] to create the array yourself.

Examples

Violates

using System.Linq;
using Xunit;

public class xUnit9014
{
    public static TheoryData<int> DataSource(params int[] multipliers) =>
        [multipliers.Aggregate(42, (left, right) => left * right)];

    [Theory]
    [MemberData(nameof(DataSource), 2)]
    public void TestMethod(int _)
    { }
}

Does not violate

using System.Linq;
using Xunit;

public class xUnit9014
{
    public static TheoryData<int> DataSource(int[] multipliers) =>
        [multipliers.Aggregate(42, (left, right) => left * right)];

    [Theory]
    [MemberData(nameof(DataSource), new[] { 2 })]
    public void TestMethod(int _)
    { }
}