private void Assert(AstFilter result, string path, BsonValue divisor, BsonValue remainder)
{
var fieldOperationFilter = result.Should().BeOfType <AstFieldOperationFilter>().Subject;
fieldOperationFilter.Field.Path.Should().Be(path);
var modFilterOperation = fieldOperationFilter.Operation.Should().BeOfType <AstModFilterOperation>().Subject;
modFilterOperation.Divisor.Should().Be(divisor);
modFilterOperation.Remainder.Should().Be(remainder);
}