def it_uses_batch_size():
with zest.mock(zap._cpu_count) as m:
sl = zap._make_batch_slices(_batch_size=2,
n_rows=6,
_limit_slice=None)
assert sl == [(0, 2), (2, 4), (4, 6)]
assert not m.called()
def it_limits_from_start():
sl = zap._make_batch_slices(_batch_size=2,
n_rows=6,
_limit_slice=slice(2, 6))
assert sl == [
(2, 4),
(4, 6),
]
def it_solves_for_batch_size_by_scaling_the_cpu_count():
with zest.mock(zap._cpu_count, returns=2):
sl = zap._make_batch_slices(_batch_size=None,
n_rows=32,
_limit_slice=None)
assert sl == [
(0, 3),
(3, 6),
(6, 9),
(9, 12),
(12, 15),
(15, 18),
(18, 21),
(21, 24),
(24, 27),
(27, 30),
(30, 32),
]
def it_raises_on_illegal_batch_size():
with zest.raises(ValueError):
zap._make_batch_slices(_batch_size=-5,
n_rows=10,
_limit_slice=None)
def it_handles_zero_rows():
sl = zap._make_batch_slices(_batch_size=10,
n_rows=0,
_limit_slice=None)
assert sl == []
def it_handles_one_large_batch():
sl = zap._make_batch_slices(_batch_size=10,
n_rows=6,
_limit_slice=None)
assert sl == [(0, 6)]
def it_handles_odd():
sl = zap._make_batch_slices(_batch_size=5, n_rows=6, _limit_slice=None)
assert sl == [(0, 5), (5, 6)]
def it_solves_for_batch_size_by_scaling_the_cpu_count_and_clamps():
with zest.mock(zap._cpu_count, returns=2):
sl = zap._make_batch_slices(_batch_size=None,
n_rows=6,
_limit_slice=None)
assert sl == [(0, 2), (2, 4), (4, 6)]
