v2 v3 AOT   Error

xUnit1037

"There are fewer arguments than required by the parameters of the test method"

Cause

When you use [MemberData] or [ClassData] with TheoryData, TheoryDataRow, or a tuple, the number of arguments must match the number of parameters in the test method. In this case, you have provided too few arguments.

Reason for rule

You must provide the correct number of arguments to the test method to run the test.

How to fix violations

To fix a violation of this rule, either add more arguments to match the method signature, or remove parameters from the test method.

Examples

Violates

Using TheoryData<> (for v2 and v3)

using Xunit;

public class xUnit1037
{
    public static TheoryData<int> PropertyData =>
        new() { 1, 2, 3 };

    [Theory]
    [MemberData(nameof(PropertyData))]
    public void TestMethod(int _1, string _2) { }
}

Using TheoryDataRow<> (for v3 only)

using Xunit;

public class xUnit1037
{
    public static IEnumerable<TheoryDataRow<int>> PropertyData =>
        [new(1), new(2), new(3)];

    [Theory]
    [MemberData(nameof(PropertyData))]
    public void TestMethod(int _1, string _2) { }
}

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

public class ClassRowData : 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 xUnit1037
{
    [Theory]
    [ClassData(typeof(ClassRowData))]
    public void TestMethod(int _1, string _2) { }
}

Using a tuple (for v3 only)

using Xunit;

public class xUnit1037
{
    public static IEnumerable<(int, string)> PropertyData =>
        [(1, "Hello"), (2, "there"), (3, "world")];

    [Theory]
    [MemberData(nameof(PropertyData))]
    public void TestMethod(int _1, string _2, double _3) { }
}

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

public class ClassRowData : IEnumerable<(int, string)>
{
    public IEnumerator<(int, string)> GetEnumerator()
    {
        yield return (1, "Hello");
        yield return (2, "there");
        yield return (3, "world");
    }

    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
}

public class xUnit1037
{
    [Theory]
    [ClassData(typeof(ClassRowData))]
    public void TestMethod(int _1, string _2, double _3) { }
}

Does not violate

Using TheoryData<> (for v2 and v3)

Fix by adding an argument:

using Xunit;

public class xUnit1037
{
    public static TheoryData<int, string> PropertyData =>
        new() { { 1, "Hello" }, { 2, "World" } };

    [Theory]
    [MemberData(nameof(PropertyData))]
    public void TestMethod(int _1, string _2) { }
}

Fix by removing a parameter:

using Xunit;

public class xUnit1037
{
    public static TheoryData<int> PropertyData =>
        new() { 1, 2, 3 };

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

Using TheoryDataRow<> (for v3 only)

Fix by adding an argument:

using System.Collections.Generic;
using Xunit;

public class xUnit1037
{
    public static IEnumerable<TheoryDataRow<int, string>> PropertyData =>
        [new(1, "Hello"), new(2, "World")];

    [Theory]
    [MemberData(nameof(PropertyData))]
    public void TestMethod(int _1, string _2) { }
}

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

public class ClassRowData : IEnumerable<TheoryDataRow<int, string>>
{
    public IEnumerator<TheoryDataRow<int, string>> GetEnumerator()
    {
        yield return new(1, "Hello");
        yield return new(2, "World");
    }

    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
}

public class xUnit1037
{
    [Theory]
    [ClassData(typeof(ClassRowData))]
    public void TestMethod(int _1, string _2) { }
}

Fix by removing a parameter:

using Xunit;

public class xUnit1037
{
    public static IEnumerable<TheoryDataRow<int>> PropertyData =>
        [new(1), new(2), new(3)];

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

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

public class ClassRowData : 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 xUnit1037
{
    [Theory]
    [ClassData(typeof(ClassRowData))]
    public void TestMethod(int _1) { }
}

Using a tuple (for v3 only)

Fix by adding an argument:

using Xunit;

public class xUnit1037
{
    public static IEnumerable<(int, string)> PropertyData =>
        [(1, "Hello", 21.12), (2, "there", 42.24), (3, "world", 63.36)];

    [Theory]
    [MemberData(nameof(PropertyData))]
    public void TestMethod(int _1, string _2, double _3) { }
}

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

public class ClassRowData : IEnumerable<(int, string)>
{
    public IEnumerator<(int, string)> GetEnumerator()
    {
        yield return (1, "Hello", 21.12);
        yield return (2, "there", 42.24);
        yield return (3, "world", 63.36);
    }

    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
}

public class xUnit1037
{
    [Theory]
    [ClassData(typeof(ClassRowData))]
    public void TestMethod(int _1, string _2, double _3) { }
}

Fix by removing a parameter:

using Xunit;

public class xUnit1037
{
    public static IEnumerable<(int, string)> PropertyData =>
        [(1, "Hello"), (2, "there"), (3, "world")];

    [Theory]
    [MemberData(nameof(PropertyData))]
    public void TestMethod(int _1, string _2) { }
}

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

public class ClassRowData : IEnumerable<(int, string)>
{
    public IEnumerator<(int, string)> GetEnumerator()
    {
        yield return (1, "Hello");
        yield return (2, "there");
        yield return (3, "world");
    }

    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
}

public class xUnit1037
{
    [Theory]
    [ClassData(typeof(ClassRowData))]
    public void TestMethod(int _1, string _2) { }
}