xUnit1050 Info

The class referenced by the ClassData attribute returns untyped data rows

Cause

xUnit.net v3 offers a strongly-typed TheoryDataRow<> class which can be used instead of object[] when returning member data. (Note that ITheoryDataRow and the non-generic TheoryDataRow are also untyped, and will cause this rule to trigger.)

Reason for rule

Using generic TheoryDataRow<> 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 TheoryDataRow<> type usage matches your test method parameters.

How to fix violations

To fix a violation of this rule, replace IEnumerable<object[]>, IEnumerable<ITheoryDataRow>, or IEnumerable<TheoryDataRow> with IEnumerable<TheoryDataRow<>>. This also applies to IAsyncEnumerable.

Examples

Violates

using System.Collections;
using System.Collections.Generic;
using Xunit;

public class EnumerableData : IEnumerable<object[]>
{
    public IEnumerator<object[]> GetEnumerator()
    {
        yield return [1];
        yield return [2];
        yield return [3];
    }
    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
}

public class xUnit1050
{
    [Theory]
    [ClassData(typeof(EnumerableData))]
    public void TestMethod(int _) { }
}

using System.Collections.Generic;
using System.Threading;
using Xunit;

public class AsyncEnumerableData : IAsyncEnumerable<object[]>
{
    public async IAsyncEnumerator<object[]> GetAsyncEnumerator(CancellationToken cancellationToken = default)
    {
        yield return [1];
        yield return [2];
        yield return [3];
    }
}

public class xUnit1050
{
    [Theory]
    [ClassData(typeof(AsyncEnumerableData))]
    public void TestMethod(int _) { }
}

Does not violate

using System.Collections;
using System.Collections.Generic;
using Xunit;

public class EnumerableData : IEnumerable<TheoryDataRow<int>>
{
    public IEnumerator<TheoryDataRow<int>> GetEnumerator()
    {
        yield return new(1);
        yield return new(2);
        yield return new(3);
    }
    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
}

public class xUnit1050
{
    [Theory]
    [ClassData(typeof(EnumerableData))]
    public void TestMethod(int _) { }
}

using System.Collections.Generic;
using System.Threading;
using Xunit;

public class AsyncEnumerableData : IAsyncEnumerable<TheoryDataRow<int>>
{
    public async IAsyncEnumerator<TheoryDataRow<int>> GetAsyncEnumerator(CancellationToken cancellationToken = default)
    {
        yield return new(1);
        yield return new(2);
        yield return new(3);
    }
}

public class xUnit1050
{
    [Theory]
    [ClassData(typeof(AsyncEnumerableData))]
    public void TestMethod(int _) { }
}