OWL Web Ontology Language Test Cases

This document contains and presents test cases for the Web Ontology Language (OWL) approved by the Web Ontology Working Group. Many of the test cases illustrate the correct usage of the Web Ontology Language (OWL), and the formal meaning of its constructs. Other test cases illustrate the resolution of issues considered by the working group. Conformance for OWL documents and OWL document checkers is specified.

Status of this document

This section describes the status of this document at the time of its publication. Other documents may supersede this document. The latest status of this document series is maintained at the W3C.

This is the Last Call Working Draft of "OWL Test Cases" for review by members of the W3C and other interested parties in the general public. The first release of this document was 4 November 2002 and the Web Ontology Working Group has made its best effort to address comments recieved since then, releasing several drafts and resolving a list of issues meanwhile. The working group seeks confirmation that comments have been addressed to the satisfaction of the community. The working group plans to keep improving these tests until they are published as a Proposed Recommendation. Please let us know (at the comments address below) if you find any errors. We would also appreciate a note describing your experience with these tests if you have developed an OWL implementation. Each test may be edited or have a change of status according to the process specified below. Further tests are being added.

The approved tests in this document have typically been successfully executed; the proposed tests are also believed to be correct.

An editors' version of this document, with the latest tests, can be found at http://www.w3.org/2002/03owlt/editors-draft/draft/. Despite this flux, the working group would value implementor feedback on the tests both in this document and those found in the editors' version. Contributions of additional tests are invited. The Last Call review period ends 27 June 2003.

Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than "work in progress". A list of current W3C Recommendations and other technical documents can be found at http://www.w3.org/TR.

Patent disclosures relevant to this specification may be found on the Working Group's public patent disclosure page.

1. Introduction

As part of the definition of the Web Ontology Language (OWL) the Web Ontology Working Group provides a set of test cases. This document presents those test cases. They are intended to provide examples for, and clarification of, the normative definition of OWL found in [OWL Semantics and Abstract Syntax] to which this document is subsidiary.

This document describes the various types of test used and the format in which the tests are presented. Alternative formats of the test collection are provided. These are intended to be suitable for use by OWL developers in test harnesses, possibly as part of a test driven development process, such as Extreme Programming [XP]. The format of the Manifest files used as part of these alternative formats is described.

This document describes the process for conflict resolution and errata related to these tests.

In the non-normative appendices, this document also describes the process for creation and approval of these tests.

Further appendices show further proposed tests that are awaiting resolution by the working group.

1.1. Conformance and Scope

However, the test cases do not constitute a conformance test suite for OWL, since they are silent on several important issues. This document cannot be considered a complete specification of OWL.

The tests illustrate issue resolutions, and illustrate the use and meaning of the terms in the OWL namespace.

There are other miscellaneous tests: some arising in the literature, and in preexisting systems; others intending to show the difficulty of complete implementations of OWL Full.

2. Deliverables (Normative)

Note: Other files can be found under the top URL of the web-site which are not part of the deliverable.

[[EDITORS' NOTE: Do we need index files for the web site that clarify which parts are part of the deliverable and which are not?]]

2.1. Normative Status

Of the deliverables the only normative tests are those included in this document. All other deliverables are informative. Moreover, the recommendation document is informative except for the conformance statements, the test data (specified in RDF/XML [RDF/XML Syntax]), and the supporting documentation.

3. Test Types (Normative)

Each test consists of one or more RDF/XML documents and a Manifest file. Tests of one document indicate some property of that document when viewed as an OWL knowledge base. Tests of two or more documents indicate a relationship between the two documents when viewed as OWL knowledge bases.

The Manifest file is named ManifestNNN.rdf (The NNN is replaced by the test number). It contains metadata (in RDF) indicating the test type, and describing the test.

3.1. Tests for Incorrect Use of OWL Namespace

These tests use one document. It is named badNNN.rdf. This document includes a use of the OWL namespace with a local name that is not defined by the OWL recommendation. An OWL Syntax checker SHOULD give a warning.

Note: These tests are intended to help migration from DAML+OIL [DAML+OIL], since the local names chosen are defined in the DAML+OIL namespace.

3.2. Entailment Tests

These tests use two documents. One is named premisesNNN.rdf, the other is named conclusionsNNN.rdf. The conclusions are entailed by the premises. Such entailment is defined by the OWL semantics [OWL Semantics and Abstract Syntax], (see also OWL Full entailment).

3.3. Non-Entailment Tests

These tests use two documents. One is named premisesNNN.rdf, the other is named nonconclusionsNNN.rdf. The nonconclusions are not entailed by the premises. Such entailment is defined by the OWL semantics [OWL Semantics and Abstract Syntax], (see also OWL Full entailment).

3.4. True Tests

These tests use one document. It is named conclusionsNNN.rdf. The conclusions follow from the OWL semantics [OWL Semantics and Abstract Syntax]. These tests are a special case of the entailment tests in which the premises are empty.

3.5. OWL for OWL Tests

These tests use one document. It is named conclusionsNNN.rdf. These are a special case of true tests. The conclusions follow from the OWL Full semantics [OWL Semantics and Abstract Syntax]. The tests are intended to illustrate how OWL Full can be used to describe its own properties and classes.

3.6. Consistency Tests

3.7. Inconsistency Tests

3.8. Import Entailment Tests

These tests use more than two documents. One is named premisesNNN.rdf, another is named conclusionsNNN.rdf, the rest have names like supportNNN-A.rdf. The support documents are in the imports closure of the premises document. The conclusions are entailed by the imports closure of the premises. Such entailment is defined by the OWL semantics [OWL Semantics and Abstract Syntax], (see also OWL Full entailment).

3.9. Import Level Tests

These tests use two documents. One is named importsNNN.rdf, the other is named mainNNN.rdf. These tests indicate the interaction between owl:imports and the sublanguage levels of the main document.

4. Conformance (Normative)

4.1. Document Conformance

4.1.1. Syntactic Conformance

4.1.2. Semantic Conformance

4.2. Document Checker Conformance

4.2.1. Syntax Checker

An OWL syntax checker takes a document as input, and returns one word being one of Lite, DL, Full, Other.

In addition, an OWL Syntax Checker SHOULD report a warning if the RDF graph [RDF Concepts] corresponding to the document uses any URI references starting with the prefix http://www.w3.org/2002/07/owl# except those found in the [RDF Schema for OWL].

An OWL syntax checker SHOULD report network errors occurring during the computation of the imports closure.

4.2.2. Consistency Checker

An OWL consistency checker takes a document as input, and returns one word being Consistent, Inconsistent, or Unknown.

An OWL consistency checker SHOULD report network errors occurring during the computation of the imports closure.

An OWL consistency checker MUST be sound: it MUST return Consistent only when the input document is consistent and Inconsistent only when the input document is not consistent, with respect to the datatype theory of the checker.

An OWL consistency checker is complete and terminating, if, given sufficient (but finite) resources (CPU cycles and memory) and the absence of network errors, it will always return either Consistent or Inconsistent. It has been shown that for OWL Lite and DL it is possible to construct a complete and terminating consistency checker (the languages are decidable), and that for OWL full it is not possible to construct a complete and terminating consistency checker (the language is undecidable, [Practical Reasoning]).

An OWL consistency checker SHOULD NOT return Unknown. Unknown, while sometimes needed, is not a desired response.

5. Testing an OWL Implementation (Informative)

5.1. OWL Syntax Checkers

An OWL syntax checker when presented with any of the test files must return the indicated result.

5.2. OWL Consistency Checker

6. Manifest Files (Informative)

The Manifest file follows the RDF schema developed for the RDF Test Cases [RDF Test Cases].

Specifically each test has its own Manifest file, and is identified from the URI reference formed from the Manifest file's URL with a fragment test.

Where otest is bound to http://www.w3.org/2002/03owlt/testOntology# and rtest is bound to http://www.w3.org/2000/10/rdf-tests/rdfcore/testSchema#.

The name of the original author of the test is shown using a dc:creator property, see [Dublin Core].

A description of the test is given (using XHTML markup [XHTML]) as the value of the rtest:description property.

An issue, if any, from the OWL Issues list [OWL Issues], is the value of a rtest:issue property.

An appropriate language feature, from the OWL namespace, if any, is the value of the otest:feature property.

The input documents with the test data are found as the value of the rtest:inputDocument property or as the value of both the rtest:premiseDocument and the rtest:conclusionDocument. The support files for import entailment tests, import level tests and test imports-002 are found as the values of otest:importedPremiseDocument.

The conformance level associated with both files and tests are given with the otest:level property. The value for each document and test is one of otest:Full, otest:DL, otest:Lite or otest:Other (documents only).

The datatypes used in the test are given with the otest:usedDatatype property or with one of its subproperties: otest:supportedDatatype or otest:notSupportedDatatype. These indicate that the test is only valid when the datatype is supported or not supported respectively by the datatype theory being used.

7. The OWL Tests (Normative)

7.3. Additional Description Logic Tests

These tests are ones that are either known from the literature (for instance, from [Heinsohn et al.]), or from test suites contributed by Network Inference, or developed by the Working Group.

7.4. Miscellaneous Tests

These tests are ones that do not fit any other category. Some are taken from the [OWL Guide]; others reflect various aspects of OWL, that were not formal issues addressed by the working group.

A. Test Creation, Approval and Modification (Informative)

A.1. Creation

Tests are created by members of the working group. An (optional) test editor is provided to facilitate this. Tests are then placed in the appropriate directory in the test web site. This is done using CVS access to the W3C CVS server [W3C CVS].

When created, tests are given a status of "PROPOSED". The author of the test creates a Manifest file in the directory of the new test, identifying:

A.2. Approval

At the chair's discretion, individual tests or groups of tests are put to the working group in the weekly telecon or at a face-to-face meeting.

The working group may take account of favourable review of the tests and/or implementation reports, as well as other factors.

If the Working Group approves a test, then it is included in the test case document.

The Working Group may reject a test, in which case its status is changed to "REJECTED". This does not indicate that the converse of the test has been accepted. There may be stylistic or other grounds for rejecting technically correct tests.

The Working Group has complete discretion to approve or reject tests independent of their conformance with this process or their conformance with the OWL working drafts.

In the light of new information, and at the chairs' discretion, the working group may review any previous decision regarding any test cases. The status of "OBSOLETED" may be used where a test has ceased to be appropriate.

A.3. Modification

The editors may make editorial changes to approved and proposed tests. This includes:

B. Stylistic Preferences (Informative)

There is a preference for the following stylistic rules. None of these rules is obligatory, but test authors should be minded that it will be easier to gain working group consensus if they follow these rules.

B.1. Use of RDF/XML

B.2. Use of xml:base

Test and manifest files should have an xml:base attribute [XMLBASE] on the document element. This should show the preferred URL of the document, from which it is actually retrievable.

B.3. Use of .rdf Suffix

Test and manifest files should use the ".rdf" suffix. URIs should not. The URL used for xml:base declarations does not have a suffix.

B.4. Use of example Domains

All URLs in the test and manifest files should be retrievable web resources except for those that use domain names with "example" as the penultimate component (e.g. "http://www.example.org/ontology#prop").

B.5. Copyright

The following copyright statement should be included as an XML comment in every test file:

B.6. Description

The description should be included as an XML comment in each test file, and be included as RDF content in the Manifest file.

B.7. Directory Structure

Tests that relate principally to some owl property or class, should be put in a directory named using the local name of that property of class.

Otherwise, tests that relate to an issue should be put in a directory named like I3.4 where the issue number is taken from the OWL issue list [OWL Issues].

B.8. Test Numbering

Each file in a test should have the number of the test at the end of its name, before the suffix.

Note: the approved tests in a directory will not necessarily be contiguously numbered.

B.9. Triple Format of Test Data

Both the approved and proposed tests are shown both in RDF/XML, which is their normative form, and in a triples format. This lists the triples as subject, predicate and object, similar to the N-triples format described in [RDF Test Cases]. The following additional conventions are used:

In the N3 syntax [N3] used for namespace declarations, the first four appear as follows:

C. Proposed Tests (Informative)

C.3. Additional Description Logic Tests

These tests are ones that are either known from the literature (for instance, from [Heinsohn et al.]), or from test suites contributed by Network Inference, or developed by the Working Group.

C.4. Miscellaneous Tests

These tests are ones that do not fit any other category. Some are taken from the [OWL Guide]; others reflect various aspects of OWL, that were not formal issues addressed by the working group.

C.5. Extra Credit (Informative)

There is no expectation that any implementation will successfully run the tests in this section; any that do gain extra credit.

The intent is to illustrate the semantics of OWL, particularly OWL Full, as specified by [OWL Semantics and Abstract Syntax], with the specific goal of showing that it is possible to say things that it is not reasonable to expect an implementation to completely understand.

E. Acknowledgments (Informative)

The following people have contributed tests to this document: Sean Bechhofer, Ian Horrocks, Peter F. Patel-Schneider, Jeff Heflin, Jonathan Borden, Guide editors, Dan Connolly, Martin Dürst, Masayasu Ishikawa, Jim Hendler, and the editors.

This document is the result of extensive discussions within the Web Ontology Working Group as a whole. The members of this group working group included: Yasser al Safadi, Jean-François Baget, James Barnette, Sean Bechhofer, Jonathan Borden, Frederik Brysse, Stephen Buswell, Peter Crowther, Jos De Roo, David De Roure, Mike Dean, Larry Eshelman, Jérôme Euzenat, Dieter Fensel, Tim Finin, Nicholas Gibbins, Pat Hayes, Jeff Heflin, Ziv Hellman, James Hendler, Bernard Horan, Masahiro Hori, Ian Horrocks, Francesco Iannuzzelli, Mario Jeckle, Ruediger Klein, Ora Lassila, Alexander Maedche, Massimo Marchiori, Deborah McGuinness, Libby Miller, Enrico Motta, Leo Obrst, Laurent Olivry , Peter Patel-Schneider, Martin Pike, Marwan Sabbouh, Guus Schreiber, Shimizu Noboru, Michael Sintek, Michael Smith, Ned Smith, John Stanton, Lynn Andrea Stein, Herman ter Horst, Lynne R. Thompson, David Trastour, Frank van Harmelen, Raphael Volz, Evan Wallace, Christopher Welty, and John Yanosy.

F. Change Log

This section gives the changes resulting from last call comments on the OWL Working Drafts. In addition, other changes to the tests are also listed.

F.1. Last Call Changes

Each change is linked to the minutes where the decision was made, and the tests that changed are listed.