PropertyDataAttribute.cs :  » Testing » xUnit.net » Xunit » Extensions » C# / CSharp Open Source

using System;
using System.Collections.Generic;
using System.Reflection;

namespace Xunit.Extensions{
    /// <summary>
    /// Provides a data source for a data theory, with the data coming from a public static property on the test class.
    /// The property must return IEnumerable&lt;object[]&gt; with the test data.
    /// </summary>
    public class PropertyDataAttribute : DataAttribute
    {
        readonly string propertyName;

        /// <summary>
        /// Creates a new instance of <see cref="PropertyDataAttribute"/>/
        /// </summary>
        /// <param name="propertyName">The name of the public static property on the test class that will provide the test data</param>
        public PropertyDataAttribute(string propertyName)
        {
            this.propertyName = propertyName;
        }

        /// <summary>
        /// Returns the data to be used to test the theory.
        /// </summary>
        /// <param name="methodUnderTest">The method that is being tested</param>
        /// <param name="parameterTypes">The types of the parameters for the test method</param>
        /// <returns>The theory data, in table form</returns>
        public override IEnumerable<object[]> GetData(MethodInfo methodUnderTest, Type[] parameterTypes)
        {
            Type typeUnderTest = methodUnderTest.DeclaringType;
            PropertyInfo propInfo = typeUnderTest.GetProperty(propertyName, BindingFlags.Public | BindingFlags.Static);
            if (propInfo == null)
                throw new ArgumentException(string.Format("Could not find public static property {0} on {1}", propertyName, typeUnderTest.FullName));

            object obj = propInfo.GetValue(null, null);
            if (obj == null)
                return null;

            IEnumerable<object[]> dataItems = obj as IEnumerable<object[]>;
            if (dataItems == null)
                throw new ArgumentException(string.Format("Property {0} on {1} did not return IEnumerable<object[]>", propertyName, typeUnderTest.FullName));

            return dataItems;
        }
    }
}