xUnit1042 Info

The member referenced by the MemberData attribute returns untyped data rows

Cause

xUnit.net offers a strongly-typed TheoryData<> class which can be used instead of IEnumerable<object[]> when returning member data.

Reason for rule

Using TheoryData<> instead of IEnumerable<object[]> provides a type-safe way to provide member data for theories. The compiler can indicate when you have provided incompatible data, and several other analyzers will help ensure your TheoryData<> type usage matches your test method parameters.

How to fix violations

To fix a violation of this rule, replace IEnumerable<object[]> with TheoryData<>.

Examples

Violates

using System.Collections.Generic;
using Xunit;

public class xUnit1042
{
    public static IEnumerable<object[]> TestData = new[] { new object[] { 42 }, new object[] { 2112 } };

    [Theory]
    [MemberData(nameof(TestData))]
    public static void TestMethod(int _)
    { }
}

Does not violate

using Xunit;

public class xUnit1042
{
    public static TheoryData<int> TestData = new() { 42, 2112 };

    [Theory]
    [MemberData(nameof(TestData))]
    public static void TestMethod(int _)
    { }
}