1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
|
discard """
output: '''
Error can be caught using yield
Infix `or` raises
Infix `and` raises
All() raises
Awaiting a async procedure call raises
Awaiting a future raises
'''
"""
import asyncdispatch
# This tests the behaviour of 'await' under different circumstances.
# Specifically, when an awaited future raises an exception then `await` should
# also raise that exception by `read`'ing that future. In cases where you don't
# want this behaviour, you can use `yield`.
# https://github.com/nim-lang/Nim/issues/4170
proc thrower(): Future[void] =
result = newFuture[void]()
result.fail(newException(Exception, "Test"))
proc dummy: Future[void] =
result = newFuture[void]()
result.complete()
proc testInfixOr() {.async.} =
# Test the infix `or` operator semantics.
var fut = thrower()
var fut2 = dummy()
await fut or fut2 # Should raise!
proc testInfixAnd() {.async.} =
# Test the infix `and` operator semantics.
var fut = thrower()
var fut2 = dummy()
await fut and fut2 # Should raise!
proc testAll() {.async.} =
# Test the `all` semantics.
var fut = thrower()
var fut2 = dummy()
await all(fut, fut2) # Should raise!
proc testCall() {.async.} =
await thrower()
proc testAwaitFut() {.async.} =
var fut = thrower()
await fut # This should raise.
proc tester() {.async.} =
# Test that we can handle exceptions without 'try'
var fut = thrower()
doAssert fut.finished
doAssert fut.failed
doAssert fut.error.msg == "Test"
yield fut # We are yielding a 'Future', so no `read` occurs.
doAssert fut.finished
doAssert fut.failed
doAssert fut.error.msg == "Test"
echo("Error can be caught using yield")
fut = testInfixOr()
yield fut
doAssert fut.finished
doAssert fut.failed
echo("Infix `or` raises")
fut = testInfixAnd()
yield fut
doAssert fut.finished
doAssert fut.failed
echo("Infix `and` raises")
fut = testAll()
yield fut
doAssert fut.finished
doAssert fut.failed
echo("All() raises")
fut = testCall()
yield fut
doAssert fut.failed
echo("Awaiting a async procedure call raises")
# Test that await will read the future and raise an exception.
fut = testAwaitFut()
yield fut
doAssert fut.failed
echo("Awaiting a future raises")
waitFor(tester())
|
