/// <summary>
/// Validates that the information provided around the type discoverer
/// is valid. For example, ensures that the provided type information
/// refers to an <see cref="NUnit.Extension.DependencyInjection.Abstractions.ITypeDiscoverer" /> that can be constructed.
/// Or, in other words, that the following conditions are met:
/// <list type="bullet">
/// <item>The type discoverer type information is not null.</item>
/// <item>Type discoverer type implements the <see cref="NUnit.Extension.DependencyInjection.Abstractions.ITypeDiscoverer"/>
/// interface.</item>
/// <item>Type has a public no-args constructor or a constructor which
/// matches the provided argument type information.</item>
/// </list>
/// </summary>
/// <param name="info">
/// The details surrounding the
/// </param>
/// <exception cref="ArgumentNullException">
/// Thrown when <paramref name="info"/> has a <see
/// cref="TypeDiscovererInfo.DiscovererType" /> that is null.
/// </exception>
/// <exception cref="ArgumentOutOfRangeException">
/// Thrown when <paramref name="info"/> has a <see
/// cref="TypeDiscovererInfo.DiscovererType" /> does not
/// implement <see cref="NUnit.Extension.DependencyInjection.Abstractions.ITypeDiscoverer"/>.
/// </exception>
/// <exception cref="ArgumentOutOfRangeException">
/// Thrown when <paramref name="info"/> has a <see
/// cref="TypeDiscovererInfo.DiscovererType" /> that does not
/// have a constructor which matches the provided <see
/// cref="TypeDiscovererInfo.DiscovererArgumentTypes" />
/// </exception>
public static void AssertIsValidDiscovererType(TypeDiscovererInfo info)
{
if (info is null)
{
throw new ArgumentNullException(nameof(info), $"{nameof(info)} must be non-null.");
}
AssertIsNotNull(info.DiscovererType);
AssertImplementsProperInterface(info.DiscovererType);
AssertHasArgumentsThatMatchConstructorArguments(info);
}
/// <summary>
/// Creates an instance of the attribute specifying that the
/// <see cref="NUnit.Extension.DependencyInjection.Abstractions.ITypeDiscoverer"/> should be of type
/// <paramref name="typeDiscovererType"/>.
/// </summary>
/// <param name="typeDiscovererType">
/// The type of the <see cref="NUnit.Extension.DependencyInjection.Abstractions.ITypeDiscoverer"/> to be used.
/// </param>
/// <exception cref="ArgumentNullException">
/// Thrown when <paramref name="typeDiscovererType"/> is null.
/// </exception>
/// <exception cref="ArgumentOutOfRangeException">
/// Thrown when <paramref name="typeDiscovererType"/> does not
/// implement <see cref="NUnit.Extension.DependencyInjection.Abstractions.ITypeDiscoverer"/>.
/// </exception>
/// <exception cref="ArgumentOutOfRangeException">
/// Thrown when <paramref name="typeDiscovererType"/> does not
/// have a public no-args constructor.
/// </exception>
public NUnitTypeDiscovererAttribute(Type typeDiscovererType)
{
TypeDiscovererInfo = new TypeDiscovererInfo
{
DiscovererType = typeDiscovererType,
DiscovererArgumentTypes = new Type[] {},
DiscovererArguments = new object[] {}
};
TypeDiscovererTypeValidator.AssertIsValidDiscovererType(TypeDiscovererInfo);
}
private static void AssertHasArgumentsThatMatchConstructorArguments(TypeDiscovererInfo info)
{
var discovererType = info.DiscovererType;
var argumentTypes = info.DiscovererArgumentTypes;
var argumentTypeNames = argumentTypes.Select(x => x.FullName);
var ctorInfo = info.DiscovererType.GetConstructor(
BindingFlags.Public | BindingFlags.Instance,
null,
CallingConventions.Standard,
argumentTypes,
null);
if (ctorInfo == null)
{
throw new ArgumentOutOfRangeException(
nameof(info),
$"{discovererType.FullName} specified as {nameof(ITypeDiscoverer)} on " +
$"{nameof(NUnitTypeDiscovererAttribute)} must have a constructor which corresponds " +
$"to the argument types which were provided: {string.Join(", ", argumentTypeNames)}."
);
}
}