def test_directions():
assert_equal(lexicon.scan("north"), [("direction", "north")])
result = lexicon.scan("north south east")
assert_equal(result, [("direction", "north"), ("direction", "south"),
("direction", "east")])
result = lexicon.scan("North soutH EAST")
assert_equal(result, [("direction", "north"), ("direction", "south"),
("direction", "east")])
def test_errors():
assert_equal(lexicon.scan("ASA"), [("error", "asa")])
result = lexicon.scan("bear IAS 123")
assert_equal(result, [("noun", "bear"), ("error", "ias"), ("number", 123)])
def test_numbers():
assert_equal(lexicon.scan("1234"), [("number", 1234)])
result = lexicon.scan("3 91234")
assert_equal(result, [("number", 3), ("number", 91234)])
def test_nouns():
assert_equal(lexicon.scan("bear"), [("noun", "bear")])
result = lexicon.scan("bear princess")
assert_equal(result, [("noun", "bear"), ("noun", "princess")])
def test_stops():
assert_equal(lexicon.scan("the"), [("stop", "the")])
result = lexicon.scan("the in of")
assert_equal(result, [("stop", "the"), ("stop", "in"), ("stop", "of")])
def test_verbs():
assert_equal(lexicon.scan("go"), [("verb", "go")])
result = lexicon.scan("go kill eat")
assert_equal(result, [("verb", "go"), ("verb", "kill"), ("verb", "eat")])