def test_with_block():
let_ = (let()
| ('x', expr('x'))
| ('y', expr('y'))
)
@let_.in_()
def _(x, y):
return x + y
assert let_.end == 'xy'
def test_should_throw():
try:
(let()
| ('x', expr('x'))
| ('y', expr('y'))
).in_("hogee")
except TypeError:
assert True
else:
assert False
def test_executed():
(let() | ('x', lambda: 10)
).in_(lambda x: eq_(x, 10))
r = (let()
| ('x', lambda: 10)
| ('y', lambda: 20)
| ('size', lambda x, y: x * y)
| ('hoge', lambda x, y: 'fooo')
).in_(lambda x, y, size: 'x = {x}, y = {y}, x * y = {size}'.format(x=x, y=y, size=size))
assert r == 'x = 10, y = 20, x * y = 200'
r = [
(let()
| ('_i', lambda: str(i))
| ('r', lambda: 'even' if i % 2 == 0 else 'odd')
).in_(lambda _i, r: _i + ' is an ' + r + ' number.')
for i in range(1, 5)
]
assert r == \
['1 is an odd number.', '2 is an even number.', '3 is an odd number.', '4 is an even number.']
def test_lazy_evalucated():
'''
The let-expr module evalucate the expression is demanded as arguments.
And content of that expression would not be evalucated.
'''
watcher = LoadOrderWatcher()
(let()
| ('x', lambda: watcher.append('Iam x'))
| ('y', lambda: watcher.append('Iam y'))
| ('z', lambda y: watcher.append('Iam z'))
).in_(lambda z: None)
watcher.expected(
'Iam y',
'Iam z',
)