Add generic attributes and add class data attribute

.gitignore

@@ -355,3 +355,6 @@ MigrationBackup/
 
 # Analysis results
 *.sarif
+
+# JetBrains Rider
+.idea

src/Xunit.Combinatorial/CombinatorialClassDataAttribute.cs

@@ -0,0 +1,63 @@
+// Copyright (c) Andrew Arnott. All rights reserved.
+// Licensed under the Ms-PL license. See LICENSE file in the project root for full license information.
+
+using System.Globalization;
+using System.Reflection;
+
+namespace Xunit;
+
+/// <summary>
+///     Specifies a class that provides the values for a combinatorial test.
+/// </summary>
+public class CombinatorialClassDataAttribute : Attribute, ICombinatorialValuesProvider
+{
+    private readonly object?[] values;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="CombinatorialClassDataAttribute" /> class.
+    /// </summary>
+    /// <param name="valuesSourceType">The type of the class that provides the values for a combinatorial test.</param>
+    /// <param name="arguments">The arguments to pass to the constructor of <paramref name="valuesSourceType" />.</param>
+    public CombinatorialClassDataAttribute(Type valuesSourceType, params object[]? arguments)
+    {
+        this.values = GetValues(valuesSourceType, arguments);
+    }
+
+    /// <inheritdoc />
+    public object?[] GetValues(ParameterInfo parameter)
+    {
+        return this.values;
+    }
+
+    private static object?[] GetValues(Type valuesSourceType, object[]? args)
+    {
+        Requires.NotNull(valuesSourceType, nameof(valuesSourceType));
+
+        if (!typeof(IEnumerable<object[]>).IsAssignableFrom(valuesSourceType))
+        {
+            throw new InvalidOperationException(
+                $"The values source must be assignable to {typeof(IEnumerable<object?[]>)}).");
+        }
+
+        IEnumerable<object[]>? values;
+
+        try
+        {
+            values = (IEnumerable<object[]>)Activator.CreateInstance(
+                valuesSourceType,
+                BindingFlags.CreateInstance | BindingFlags.OptionalParamBinding,
+                null,
+                args,
+                CultureInfo.InvariantCulture);
+        }
+        catch (Exception ex)
+        {
+            throw new InvalidOperationException(
+                $"Failed to create an instance of {valuesSourceType}. " +
+                $"Please make sure the type has a public constructor and the arguments match.",
+                ex);
+        }
+
+        return values.SelectMany(rows => rows).ToArray();
+    }
+}

src/Xunit.Combinatorial/CombinatorialClassDataAttribute`1.cs

@@ -0,0 +1,24 @@
+// Copyright (c) Andrew Arnott. All rights reserved.
+// Licensed under the Ms-PL license. See LICENSE file in the project root for full license information.
+
+using System.Collections;
+
+namespace Xunit;
+
+#if NETSTANDARD2_0_OR_GREATER
+/// <inheritdoc />
+/// <typeparam name="TValueSource">The type of the class that provides the values for a combinatorial test.</typeparam>
+/// <remarks><typeparamref name="TValueSource" /> must implement <see cref="IEnumerable" />.</remarks>
+public class CombinatorialClassDataAttribute<TValueSource> : CombinatorialClassDataAttribute
+    where TValueSource : IEnumerable<object?[]>
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="CombinatorialClassDataAttribute{TValueSource}" /> class.
+    /// </summary>
+    /// <param name="arguments">The arguments to pass to the constructor of <typeparamref name="TValueSource" />.</param>
+    public CombinatorialClassDataAttribute(params object[]? arguments)
+        : base(typeof(TValueSource), arguments)
+    {
+    }
+}
+#endif

src/Xunit.Combinatorial/CombinatorialMemberDataAttribute.cs

@@ -10,13 +10,14 @@ namespace Xunit;
 /// Specifies which member should provide data for this parameter used for running the test method.
 /// </summary>
 [AttributeUsage(AttributeTargets.Parameter, AllowMultiple = true)]
-public class CombinatorialMemberDataAttribute : Attribute
+public class CombinatorialMemberDataAttribute : Attribute, ICombinatorialValuesProvider
 {
     /// <summary>
     /// Initializes a new instance of the <see cref="CombinatorialMemberDataAttribute"/> class.
     /// </summary>
     /// <param name="memberName">The name of the public static member on the test class that will provide the test data.</param>
     /// <param name="arguments">The arguments for the member (only supported for methods; ignored for everything else).</param>
+    /// <remarks>Optional parameters on methods are not supported.</remarks>
     public CombinatorialMemberDataAttribute(string memberName, params object?[]? arguments)
     {
         this.MemberName = memberName ?? throw new ArgumentNullException(nameof(memberName));
@@ -64,8 +65,14 @@ public CombinatorialMemberDataAttribute(string memberName, params object?[]? arg
             throw new ArgumentException($"Could not find public static member (property, field, or method) named '{this.MemberName}' on {type.FullName}{parameterText}.");
         }
 
-        var obj = (IEnumerable)accessor();
-        return obj.Cast<object>().ToArray();
+        var values = (IEnumerable)accessor();
+
+        if (values is IEnumerable<object[]> theoryData)
+        {
+            return theoryData.SelectMany(rows => rows).ToArray();
+        }
+
+        return values.Cast<object>().ToArray();
     }
 
     /// <summary>
@@ -75,19 +82,10 @@ public CombinatorialMemberDataAttribute(string memberName, params object?[]? arg
     /// <returns>The generic type argument for (one of) the <see cref="IEnumerable{T}"/> interface)s) implemented by the <paramref name="enumerableType"/>.</returns>
     private static TypeInfo? GetEnumeratedType(Type enumerableType)
     {
-        if (enumerableType.IsGenericType)
+        if (enumerableType.IsGenericType && enumerableType.GetGenericTypeDefinition() == typeof(IEnumerable<>))
         {
-            if (enumerableType.GetGenericTypeDefinition() == typeof(IEnumerable<>))
-            {
-                Type[] enumerableGenericTypeArgs = enumerableType.GetTypeInfo().GetGenericArguments();
-                return enumerableGenericTypeArgs[0].GetTypeInfo();
-            }
-
-            if (enumerableType.GetGenericTypeDefinition() == typeof(TheoryData<>))
-            {
-                Type[] enumerableGenericTypeArgs = enumerableType.GetTypeInfo().GetGenericArguments();
-                return enumerableGenericTypeArgs[0].GetTypeInfo();
-            }
+            Type[] enumerableGenericTypeArgs = enumerableType.GetTypeInfo().GetGenericArguments();
+            return enumerableGenericTypeArgs[0].GetTypeInfo();
         }
 
         foreach (Type implementedInterface in enumerableType.GetTypeInfo().ImplementedInterfaces)
@@ -157,6 +155,11 @@ private bool ParameterTypesCompatible(ParameterInfo[] parameters, object?[]? arg
             return false;
         }
 
+        if (parameters.Length != arguments.Length)
+        {
+            return false;
+        }
+
         for (int i = 0; i < parameters.Length; i++)
         {
             if (arguments[i] is object arg)
@@ -211,7 +214,13 @@ private bool ParameterTypesCompatible(ParameterInfo[] parameters, object?[]? arg
     /// <exception cref="ArgumentException">Throw when <paramref name="enumerableType"/> does not conform to requirements or does not produce values assignable to <paramref name="parameterInfo"/>.</exception>
     private void EnsureValidMemberDataType(Type enumerableType, Type declaringType, ParameterInfo parameterInfo)
     {
+        if (typeof(IEnumerable<object[]>).IsAssignableFrom(enumerableType))
+        {
+            return;
+        }
+
         TypeInfo? enumeratedType = GetEnumeratedType(enumerableType);
+
         if (enumeratedType is null)
         {
             throw new ArgumentException($"Member {this.MemberName} on {declaringType.FullName} must return a type that implements IEnumerable<T>.");

src/Xunit.Combinatorial/CombinatorialMemberDataAttribute`1.cs

@@ -0,0 +1,28 @@
+// Copyright (c) Andrew Arnott. All rights reserved.
+// Licensed under the Ms-PL license. See LICENSE file in the project root for full license information.
+
+namespace Xunit;
+
+#if NETSTANDARD2_0_OR_GREATER
+/// <inheritdoc />
+/// <typeparam name="T">The type of the class that provides the values for a combinatorial test.</typeparam>
+public class CombinatorialMemberDataAttribute<T> : CombinatorialMemberDataAttribute
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="CombinatorialMemberDataAttribute{T}" /> class.
+    /// </summary>
+    /// <param name="memberName">The name of the public static member on the test class that will provide the test data.</param>
+    /// <param name="arguments">The arguments for the member (only supported for methods; ignored for everything else).</param>
+    /// <remarks>Optional parameters on methods are not supported.</remarks>
+    public CombinatorialMemberDataAttribute(string memberName, params object?[]? arguments)
+        : base(memberName, arguments)
+    {
+        base.MemberType = typeof(T);
+    }
+
+    /// <summary>
+    /// Gets type to retrieve the member from.
+    /// </summary>
+    public new Type? MemberType => base.MemberType;
+}
+#endif

src/Xunit.Combinatorial/CombinatorialRandomDataAttribute.cs

@@ -1,15 +1,16 @@
-// Copyright (c) Andrew Arnott. All rights reserved.
+// Copyright (c) Andrew Arnott. All rights reserved.
 // Licensed under the Ms-PL license. See LICENSE file in the project root for full license information.
 
 using System.Globalization;
+using System.Reflection;
 
 namespace Xunit;
 
 /// <summary>
 /// Specifies which range of values for this parameter should be used for running the test method.
 /// </summary>
 [AttributeUsage(AttributeTargets.Parameter)]
-public class CombinatorialRandomDataAttribute : Attribute
+public class CombinatorialRandomDataAttribute : Attribute, ICombinatorialValuesProvider
 {
     /// <summary>
     /// Special seed value to create System.Random class without seed.
@@ -42,11 +43,11 @@ public class CombinatorialRandomDataAttribute : Attribute
     /// <value>The default value of <see cref="NoSeed"/> allows for a new seed to be used each time.</value>
     public int Seed { get; set; } = NoSeed;
 
-    /// <summary>
-    /// Gets the values that should be passed to this parameter on the test method.
-    /// </summary>
-    /// <value>An array of values.</value>
-    public object[] Values => this.values ??= this.GenerateValues();
+    /// <inheritdoc />
+    public object[] GetValues(ParameterInfo parameter)
+    {
+        return this.values ??= this.GenerateValues();
+    }
 
     private object[] GenerateValues()
     {

src/Xunit.Combinatorial/CombinatorialRangeAttribute.cs

@@ -1,14 +1,18 @@
-// Copyright (c) Andrew Arnott. All rights reserved.
+// Copyright (c) Andrew Arnott. All rights reserved.
 // Licensed under the Ms-PL license. See LICENSE file in the project root for full license information.
 
+using System.Reflection;
+
 namespace Xunit;
 
 /// <summary>
 /// Specifies which range of values for this parameter should be used for running the test method.
 /// </summary>
 [AttributeUsage(AttributeTargets.Parameter)]
-public class CombinatorialRangeAttribute : Attribute
+public class CombinatorialRangeAttribute : Attribute, ICombinatorialValuesProvider
 {
+    private readonly object[] values;
+
     /// <summary>
     /// Initializes a new instance of the <see cref="CombinatorialRangeAttribute"/> class.
     /// </summary>
@@ -30,7 +34,7 @@ public CombinatorialRangeAttribute(int from, int count)
             values[i] = from + i;
         }
 
-        this.Values = values;
+        this.values = values;
     }
 
     /// <summary>
@@ -75,7 +79,7 @@ public CombinatorialRangeAttribute(int from, int to, int step)
             values[i] = from + (i * step);
         }
 
-        this.Values = values;
+        this.values = values;
     }
 
     /// <summary>
@@ -99,7 +103,7 @@ public CombinatorialRangeAttribute(uint from, uint count)
             values[i] = from + i;
         }
 
-        this.Values = values;
+        this.values = values;
     }
 
     /// <summary>
@@ -140,12 +144,12 @@ public CombinatorialRangeAttribute(uint from, uint to, uint step)
             }
         }
 
-        this.Values = values.Cast<object>().ToArray();
+        this.values = values.Cast<object>().ToArray();
     }
 
-    /// <summary>
-    /// Gets the values that should be passed to this parameter on the test method.
-    /// </summary>
-    /// <value>An array of values.</value>
-    public object[] Values { get; }
+    /// <inheritdoc />
+    public object[] GetValues(ParameterInfo parameter)
+    {
+        return this.values;
+    }
 }

src/Xunit.Combinatorial/CombinatorialValuesAttribute.cs

@@ -1,14 +1,18 @@
-// Copyright (c) Andrew Arnott. All rights reserved.
+// Copyright (c) Andrew Arnott. All rights reserved.
 // Licensed under the Ms-PL license. See LICENSE file in the project root for full license information.
 
+using System.Reflection;
+
 namespace Xunit;
 
 /// <summary>
 /// Specifies which values for this parameter should be used for running the test method.
 /// </summary>
 [AttributeUsage(AttributeTargets.Parameter)]
-public class CombinatorialValuesAttribute : Attribute
+public class CombinatorialValuesAttribute : Attribute, ICombinatorialValuesProvider
 {
+    private readonly object?[] values;
+
     /// <summary>
     /// Initializes a new instance of the <see cref="CombinatorialValuesAttribute"/> class.
     /// </summary>
@@ -17,12 +21,12 @@ public CombinatorialValuesAttribute(params object?[]? values)
     {
         // When values is `null`, it's because the user passed in `null` as the only value and C# interpreted it as a null array.
         // Re-interpret that.
-        this.Values = values ?? new object?[] { null };
+        this.values = values ?? new object?[] { null };
     }
 
-    /// <summary>
-    /// Gets the values that should be passed to this parameter on the test method.
-    /// </summary>
-    /// <value>An array of values.</value>
-    public object?[] Values { get; }
+    /// <inheritdoc />
+    public object?[] GetValues(ParameterInfo parameter)
+    {
+        return this.values;
+    }
 }

src/Xunit.Combinatorial/ICombinatorialValuesProvider.cs

@@ -0,0 +1,19 @@
+// Copyright (c) Andrew Arnott. All rights reserved.
+// Licensed under the Ms-PL license. See LICENSE file in the project root for full license information.
+
+using System.Reflection;
+
+namespace Xunit;
+
+/// <summary>
+/// Defines a class that provides values for a parameter on a test method.
+/// </summary>
+public interface ICombinatorialValuesProvider
+{
+    /// <summary>
+    /// Gets the values that should be passed to this parameter on the test method.
+    /// </summary>
+    /// <param name="parameter">The parameter to get values for.</param>
+    /// <returns>An array of values.</returns>
+    object?[] GetValues(ParameterInfo parameter);
+}