/// <summary>
/// Verifies that the given collection contains only a single
/// element of the given type.
/// </summary>
/// <typeparam name="T">The collection type.</typeparam>
/// <param name="collection">The collection.</param>
/// <returns>The single item in the collection.</returns>
/// <exception cref="SingleException">Thrown when the collection does not contain
/// exactly one element.</exception>
public static T Single <T>(this IAssert assert, IEnumerable <T> collection)
{
return(assert.Single(collection, item => true));
}