def can_infer(expected_facts):
"""
Method that initiates the method chaining by constructing an ``InferenceAssertion`` object
with the given expected facts.
.. code-block:: python
can_infer(":Icaro a :Mortal")
This function is in ``diderot.__init__``, so it can be imported simply with
``from diderot import can_infer``.
"""
expected_facts = parse_facts(expected_facts)
return InferenceAssertion(expected_facts=expected_facts)
def from_facts(self, facts):
"""
This function is part of the method chaining and receives facts as argument,
so that the inference is triggered using ``self.expected_facts`` and ``facts``.
As part of the method chaining this function returns the object itself, after running the
inference process, which updates the ``self.assertion_value`` member.
.. code-block:: python
can_infer(":Icaro a :Mortal").from_facts(":Icaro a :Human . :Human rdfs:subClassOf :Mortal")
"""
self.facts = parse_facts(facts)
self._infer()
return self
def from_ontology(self, ontology):
"""
This function is part of the method chaining and receives the ontology as argument.
.. code-block:: python
can_answer("SELECT * WHERE {?s ?p ?o}").from_ontology(":Icaro a :Human . :Human rdfs:subClassOf :Mortal")
If the query to the selected ontology returns ``True`` (for ``ASK`` queries)
or a non-empty result (for ``SELECT`` queries), ``self.assertion_value`` is set
to ``True``. Otherwise, ``self.assertion_value`` is set to ``False``.
If the query is not a ``ASK`` or ``SELECT`` query, a ``RuntimeError`` is raised.
As part of the method chaining this function returns the object itself.
"""
ontology_graph = parse_facts(ontology)
query_result = ontology_graph.query(self.question)
if query_result.construct:
raise RuntimeError("Only SELECT or ASK queries are accepted")
if query_result.askAnswer:
self.assertion_value = query_result.askAnswer[0]
if not self.assertion_value:
ASSERTION_ERROR_MESSAGE = "ASK query returned false.\n Query: {0}"
self.assertion_error_message = ASSERTION_ERROR_MESSAGE.format(self.question)
elif query_result.allVariables is not None:
self.assertion_value = len(query_result.selected) > 0
if not self.assertion_value:
ASSERTION_ERROR_MESSAGE = "SELECT query result is empty.\n Query: {0}"
self.assertion_error_message = ASSERTION_ERROR_MESSAGE.format(self.question)
else:
self.query_result = query_result
else:
raise RuntimeError("Unexpected exception parsing SPARQL query results:\n {0}".format(self.query_result))
return self
def test_parse_facts_invalid_type(self):
self.assertRaises(RuntimeError, parse_facts(10))
def test_parse_facts_rdflib_graph(self):
graph = get_empty_graph()
graph.add((URIRef(":Icaro"), RDF.type, URIRef(":Mortal")))
self.assertEqual(graph, parse_facts(graph))
def test_parse_facts_from_string(self, parse_ttl_string):
mocked_open = mock_open()
mocked_open.side_effect = IOError
with patch("diderot.utils.urlopen", mocked_open):
parse_facts(TTL_STRING)
parse_ttl_string.assert_called_with(TTL_STRING)
def test_parse_facts_from_file_path(self, parse_ttl_file):
parse_facts("db/test.n3", begin=2, end=3)
parse_ttl_file.assert_called_with(os.getcwd() + "/db/test.n3", 2, 3)
def test_parse_facts_from_uri(self, parse_ttl_string):
mocked_open = mock_open()
mocked_open.return_value = StringIO(TTL_STRING)
with patch("diderot.utils.urlopen", mocked_open):
parse_facts("http://test")
parse_ttl_string.assert_called_with(TTL_STRING)
