def test_cache():
my_rdd = Context().parallelize([1, 2, 3, 4], 2)
my_rdd = my_rdd.map(lambda x: x*x).cache()
print('no exec until here')
print(my_rdd.first())
print('executed map on first partition only')
print(my_rdd.collect())
print('now map() was executed on all partitions and should '
'not be executed again')
print(my_rdd.collect())
assert len(my_rdd.collect()) == 4 and 16 in my_rdd.collect()
def test_first_partitions():
my_rdd = Context().parallelize([1, 2, 2, 4, 1, 3, 5, 9], 3)
print(my_rdd.first())
assert my_rdd.first() == 1
