SqlExceptionBuilder - Helper class to create an SQLException for unit testing

SqlExceptionBuilder.cs

//
// Helper class to create an SQLException for unit testing, see:
// https://stackoverflow.com/questions/11976996/moq-and-throwing-a-sqlexception
// 
// Usage:
// var sqlException1 = new SqlExceptionBuilder()
//     .WithErrorNumber(50000)
//     .WithErrorMessage("Database exception occured...")
//     .Build();
//
private class SqlExceptionBuilder
{
    private int errorNumber;
    private string errorMessage;

    public SqlException Build()
    {
        SqlError error = this.CreateError();
        SqlErrorCollection errorCollection = this.CreateErrorCollection(error);
        SqlException exception = this.CreateException(errorCollection);

        return exception;
    }

    public SqlExceptionBuilder WithErrorNumber(int number)
    {
        this.errorNumber = number;
        return this;
    }

    public SqlExceptionBuilder WithErrorMessage(string message)
    {
        this.errorMessage = message;
        return this;
    }

    private SqlError CreateError()
    {
        // Create instance via reflection...
        var ctors = typeof(SqlError).GetConstructors(BindingFlags.NonPublic | BindingFlags.Instance);
        var firstSqlErrorCtor = ctors.FirstOrDefault(ctor => ctor.GetParameters().Count() == 7); // Need a specific constructor!
        SqlError error = firstSqlErrorCtor.Invoke(new object[] {
            this.errorNumber,
            new byte(),
            new byte(),
            string.Empty,
            string.Empty,
            string.Empty,
            new int()
        }) as SqlError;
        return error;
    }

    private SqlErrorCollection CreateErrorCollection(SqlError error)
    {
        // Create instance via reflection...
        var sqlErrorCollectionCtor = typeof(SqlErrorCollection).GetConstructors(BindingFlags.NonPublic | BindingFlags.Instance)[0];
        SqlErrorCollection errorCollection = sqlErrorCollectionCtor.Invoke(new object[] { }) as SqlErrorCollection;

        // Add error...
        typeof(SqlErrorCollection).GetMethod("Add", BindingFlags.NonPublic | BindingFlags.Instance).Invoke(errorCollection, new object[] { error });

        return errorCollection;
    }

    private SqlException CreateException(SqlErrorCollection errorCollection)
    {
        // Create instance via reflection...
        var ctor = typeof(SqlException).GetConstructors(BindingFlags.NonPublic | BindingFlags.Instance)[0];
        SqlException sqlException = ctor.Invoke(new object[] { 
            // With message and error collection...
            this.errorMessage,
            errorCollection,
            null,
            Guid.NewGuid()
        }) as SqlException;

        return sqlException;
    }
}