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from test.data import bob, cheese, hates, likes, michel, pizza, tarek
from rdflib import Graph
class TestGraphSlice:
def test_slice(self):
"""
We pervert the slice object,
and use start, stop, step as subject, predicate, object
all operations return generators over full triples
"""
def sl(x, y):
return len(list(x)) == y
def soe(x, y):
return set([a[2] for a in x]) == set(y) # equals objects
g = Graph()
g.add((tarek, likes, pizza))
g.add((tarek, likes, cheese))
g.add((michel, likes, pizza))
g.add((michel, likes, cheese))
g.add((bob, likes, cheese))
g.add((bob, hates, pizza))
g.add((bob, hates, michel)) # gasp!
# Single terms are all trivial:
# single index slices by subject, i.e. return triples((x,None,None))
# tell me everything about "tarek"
sl(g[tarek], 2)
# single slice slices by s,p,o, with : used to split
# tell me everything about "tarek" (same as above)
sl(g[tarek::], 2)
# give me every "likes" relationship
sl(g[:likes:], 5)
# give me every relationship to pizza
sl(g[::pizza], 3)
# give me everyone who likes pizza
sl(g[:likes:pizza], 2)
# does tarek like pizza?
assert g[tarek:likes:pizza] is True
# More intesting is using paths
# everything hated or liked
sl(g[: hates | likes], 7)
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