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

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

namespace Xunit.Extensions{
    /// <summary>
    /// Represents an implementation of <see cref="DataAttribute"/> which uses an
    /// instance of <see cref="IDataAdapter"/> to get the data for a <see cref="TheoryAttribute"/>
    /// decorated test method.
    /// </summary>
    public abstract class DataAdapterDataAttribute : DataAttribute
    {
        /// <summary>
        /// Gets the data adapter to be used to retrieve the test data.
        /// </summary>
        protected abstract IDataAdapter DataAdapter { get; }

        /// <inheritdoc/>
        public override IEnumerable<object[]> GetData(MethodInfo methodUnderTest, Type[] parameterTypes)
        {
            DataSet dataSet = new DataSet();
            IDataAdapter adapter = DataAdapter;

            try
            {
                adapter.Fill(dataSet);

                foreach (DataRow row in dataSet.Tables[0].Rows)
                    yield return ConvertParameters(row.ItemArray, parameterTypes);
            }
            finally
            {
                if (adapter != null && adapter is IDisposable)
                    ((IDisposable)adapter).Dispose();
            }
        }

        object[] ConvertParameters(object[] values, Type[] parameterTypes)
        {
            object[] result = new object[values.Length];

            for (int idx = 0; idx < values.Length; idx++)
                result[idx] = ConvertParameter(values[idx], idx >= parameterTypes.Length ? null : parameterTypes[idx]);

            return result;
        }

        /// <summary>
        /// Converts a parameter to its destination parameter type, if necessary.
        /// </summary>
        /// <param name="parameter">The parameter value</param>
        /// <param name="parameterType">The destination parameter type (null if not known)</param>
        /// <returns>The converted parameter value</returns>
        protected virtual object ConvertParameter(object parameter, Type parameterType)
        {
            if (parameter is DBNull)
                return null;

            return parameter;
        }
    }
}