The proposed conformance tests should be grouped into buckets, each of which test a specific section of the DFDL spec. Here is a proposed structure. Optional features need to have their tests in separate buckets, so that partly drives the grouping. Please review for completeness. Bucket (prefix gives spec section) What is tested Notes 7_property_syntax attribute, element and short form equivalence 8_default_format default format annotation 8_define_format defineFormat annotation & use of ref 8_combining_properties combining properties from references 11_encodings_1 range of encodings (core) 11_encodings_2 range of encodings (rest) optional 12_1_alignment_bytes explicit and implicit alignment (bytes) 12_1_alignment_bits alignment (bits) optional 12_2_delimiters delimiters 12_3_length_explicit_bytes explicit lengths (bytes) 12_3_length_delimited_text delimited lengths for text 12_3_length_delimited_binary delimited lengths for binary optional 12_3_length_implicit implicit lengths (bytes) 12_3_length_prefixed prefix lengths optional 12_3_length_pattern pattern lengths 12_3_length_end_of_parent end of parent lengths 12_3_length_explicit_bits lengths (bits) optional 13_4_strings_text text strings 13_6_numbers_text_standard standard text numbers 13_6_numbers_text_zoned zoned text numbers optional 13_7_numbers_binary binary numbers, incl float 13_7_numbers_binary_packed packed decimal binary numbers optional 13_9_boolean_text text booleans 13_10_boolean_binary binary booleans 13_12_calendar_text text calendars 13_13_calendar_binary_packed packed decimal binary calendars optional 13_13_calendar_binary binary calendars 13_2_text_escape_schemes text data escaped optional 13_3_text_bidi bidi text (all types) optional 13_simple_type_restrictions creating own simple types optional 13_16_nils nil handling optional 13_17_defaults default handling optional 14_sequences_basic basic sequences incl initiated 14_2_sequences_separated sequences with separators 14_3_sequences_unordered unordered sequences optional 14_4_sequences_floating sequences with floaters optional 14_5_sequences_hidden hidden groups optional 15_choices_basic basic choices incl fixed length and initiated 15_choices_discriminated use of discriminators optional 16_arrays basic arrays, all types 16_arrays_discriminated use of discriminators optional 17_calculated_values input and output optional validation validation against facets etc optional 7_assert basic assert optional 7_discriminator basic discriminator optional 7_assert_pattern assert with regexps optional 7_discriminator_pattern discriminator with regexps optional 23_expressions all kinds of expression and all XPath functions 23_expressions_variables variables in expressions optional 23_expressions_variables_external externally set variables in expressions optional Regards Steve Hanson Strategy, Common Transformation & DFDL Co-Chair, OGF DFDL WG IBM SWG, Hursley, UK, smh@uk.ibm.com, tel +44-(0)1962-815848 Unless stated otherwise above: IBM United Kingdom Limited - Registered in England and Wales with number 741598. Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU