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
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
|
from pytest import raises
from promise import Promise, async_instance
from promise.dataloader import DataLoader
def id_loader(**options):
load_calls = []
resolve = options.pop("resolve", Promise.resolve)
def fn(keys):
load_calls.append(keys)
return resolve(keys)
identity_loader = DataLoader(fn, **options)
return identity_loader, load_calls
def test_build_a_simple_data_loader():
def call_fn(keys):
return Promise.resolve(keys)
identity_loader = DataLoader(call_fn)
promise1 = identity_loader.load(1)
assert isinstance(promise1, Promise)
value1 = promise1.get()
assert value1 == 1
def test_supports_loading_multiple_keys_in_one_call():
def call_fn(keys):
return Promise.resolve(keys)
identity_loader = DataLoader(call_fn)
promise_all = identity_loader.load_many([1, 2])
assert isinstance(promise_all, Promise)
values = promise_all.get()
assert values == [1, 2]
promise_all = identity_loader.load_many([])
assert isinstance(promise_all, Promise)
values = promise_all.get()
assert values == []
def test_batches_multiple_requests():
@Promise.safe
def do():
identity_loader, load_calls = id_loader()
promise1 = identity_loader.load(1)
promise2 = identity_loader.load(2)
p = Promise.all([promise1, promise2])
value1, value2 = p.get()
assert value1 == 1
assert value2 == 2
assert load_calls == [[1, 2]]
do().get()
def test_batches_multiple_requests_with_max_batch_sizes():
@Promise.safe
def do():
identity_loader, load_calls = id_loader(max_batch_size=2)
promise1 = identity_loader.load(1)
promise2 = identity_loader.load(2)
promise3 = identity_loader.load(3)
p = Promise.all([promise1, promise2, promise3])
value1, value2, value3 = p.get()
assert value1 == 1
assert value2 == 2
assert value3 == 3
assert load_calls == [[1, 2], [3]]
do().get()
def test_coalesces_identical_requests():
@Promise.safe
def do():
identity_loader, load_calls = id_loader()
promise1 = identity_loader.load(1)
promise2 = identity_loader.load(1)
assert promise1 == promise2
p = Promise.all([promise1, promise2])
value1, value2 = p.get()
assert value1 == 1
assert value2 == 1
assert load_calls == [[1]]
do().get()
def test_caches_repeated_requests():
@Promise.safe
def do():
identity_loader, load_calls = id_loader()
a, b = Promise.all([identity_loader.load("A"), identity_loader.load("B")]).get()
assert a == "A"
assert b == "B"
assert load_calls == [["A", "B"]]
a2, c = Promise.all(
[identity_loader.load("A"), identity_loader.load("C")]
).get()
assert a2 == "A"
assert c == "C"
assert load_calls == [["A", "B"], ["C"]]
a3, b2, c2 = Promise.all(
[
identity_loader.load("A"),
identity_loader.load("B"),
identity_loader.load("C"),
]
).get()
assert a3 == "A"
assert b2 == "B"
assert c2 == "C"
assert load_calls == [["A", "B"], ["C"]]
do().get()
def test_clears_single_value_in_loader():
@Promise.safe
def do():
identity_loader, load_calls = id_loader()
a, b = Promise.all([identity_loader.load("A"), identity_loader.load("B")]).get()
assert a == "A"
assert b == "B"
assert load_calls == [["A", "B"]]
identity_loader.clear("A")
a2, b2 = Promise.all(
[identity_loader.load("A"), identity_loader.load("B")]
).get()
assert a2 == "A"
assert b2 == "B"
assert load_calls == [["A", "B"], ["A"]]
do().get()
def test_clears_all_values_in_loader():
@Promise.safe
def do():
identity_loader, load_calls = id_loader()
a, b = Promise.all([identity_loader.load("A"), identity_loader.load("B")]).get()
assert a == "A"
assert b == "B"
assert load_calls == [["A", "B"]]
identity_loader.clear_all()
a2, b2 = Promise.all(
[identity_loader.load("A"), identity_loader.load("B")]
).get()
assert a2 == "A"
assert b2 == "B"
assert load_calls == [["A", "B"], ["A", "B"]]
do().get()
def test_does_not_replace_cache_map():
@Promise.safe
def do():
identity_loader, _ = id_loader()
a, b = Promise.all([identity_loader.load("A"), identity_loader.load("B")]).get()
assert a == "A"
assert b == "B"
cache_map = identity_loader._promise_cache
identity_loader.clear_all()
assert id(identity_loader._promise_cache) == id(cache_map)
do().get()
def test_allows_priming_the_cache():
@Promise.safe
def do():
identity_loader, load_calls = id_loader()
identity_loader.prime("A", "A")
a, b = Promise.all([identity_loader.load("A"), identity_loader.load("B")]).get()
assert a == "A"
assert b == "B"
assert load_calls == [["B"]]
do().get()
def test_does_not_prime_keys_that_already_exist():
@Promise.safe
def do():
identity_loader, load_calls = id_loader()
identity_loader.prime("A", "X")
a1 = identity_loader.load("A").get()
b1 = identity_loader.load("B").get()
assert a1 == "X"
assert b1 == "B"
identity_loader.prime("A", "Y")
identity_loader.prime("B", "Y")
a2 = identity_loader.load("A").get()
b2 = identity_loader.load("B").get()
assert a2 == "X"
assert b2 == "B"
assert load_calls == [["B"]]
do().get()
# Represents Errors
def test_resolves_to_error_to_indicate_failure():
@Promise.safe
def do():
def resolve(keys):
mapped_keys = [
key if key % 2 == 0 else Exception("Odd: {}".format(key))
for key in keys
]
return Promise.resolve(mapped_keys)
even_loader, load_calls = id_loader(resolve=resolve)
with raises(Exception) as exc_info:
even_loader.load(1).get()
assert str(exc_info.value) == "Odd: 1"
value2 = even_loader.load(2).get()
assert value2 == 2
assert load_calls == [[1], [2]]
do().get()
def test_can_represent_failures_and_successes_simultaneously():
@Promise.safe
def do():
def resolve(keys):
mapped_keys = [
key if key % 2 == 0 else Exception("Odd: {}".format(key))
for key in keys
]
return Promise.resolve(mapped_keys)
even_loader, load_calls = id_loader(resolve=resolve)
promise1 = even_loader.load(1)
promise2 = even_loader.load(2)
with raises(Exception) as exc_info:
promise1.get()
assert str(exc_info.value) == "Odd: 1"
value2 = promise2.get()
assert value2 == 2
assert load_calls == [[1, 2]]
do().get()
def test_caches_failed_fetches():
@Promise.safe
def do():
def resolve(keys):
mapped_keys = [Exception("Error: {}".format(key)) for key in keys]
return Promise.resolve(mapped_keys)
error_loader, load_calls = id_loader(resolve=resolve)
with raises(Exception) as exc_info:
error_loader.load(1).get()
assert str(exc_info.value) == "Error: 1"
with raises(Exception) as exc_info:
error_loader.load(1).get()
assert str(exc_info.value) == "Error: 1"
assert load_calls == [[1]]
do().get()
def test_caches_failed_fetches():
@Promise.safe
def do():
identity_loader, load_calls = id_loader()
identity_loader.prime(1, Exception("Error: 1"))
with raises(Exception) as exc_info:
identity_loader.load(1).get()
assert load_calls == []
do().get()
# It is resilient to job queue ordering
# def test_batches_loads_occuring_within_promises():
# @Promise.safe
# def do():
# identity_loader, load_calls = id_loader()
# values = Promise.all([
# identity_loader.load('A'),
# Promise.resolve(None).then(lambda v: Promise.resolve(None)).then(
# lambda v: identity_loader.load('B')
# )
# ]).get()
# assert values == ['A', 'B']
# assert load_calls == [['A', 'B']]
# do().get()
def test_catches_error_if_loader_resolver_fails():
@Promise.safe
def do():
def do_resolve(x):
raise Exception("AOH!")
a_loader, a_load_calls = id_loader(resolve=do_resolve)
with raises(Exception) as exc_info:
a_loader.load("A1").get()
assert str(exc_info.value) == "AOH!"
do().get()
def test_can_call_a_loader_from_a_loader():
@Promise.safe
def do():
deep_loader, deep_load_calls = id_loader()
a_loader, a_load_calls = id_loader(
resolve=lambda keys: deep_loader.load(tuple(keys))
)
b_loader, b_load_calls = id_loader(
resolve=lambda keys: deep_loader.load(tuple(keys))
)
a1, b1, a2, b2 = Promise.all(
[
a_loader.load("A1"),
b_loader.load("B1"),
a_loader.load("A2"),
b_loader.load("B2"),
]
).get()
assert a1 == "A1"
assert b1 == "B1"
assert a2 == "A2"
assert b2 == "B2"
assert a_load_calls == [["A1", "A2"]]
assert b_load_calls == [["B1", "B2"]]
assert deep_load_calls == [[("A1", "A2"), ("B1", "B2")]]
do().get()
def test_dataloader_clear_with_missing_key_works():
@Promise.safe
def do():
def do_resolve(x):
return x
a_loader, a_load_calls = id_loader(resolve=do_resolve)
assert a_loader.clear("A1") == a_loader
do().get()
def test_wrong_loader_return_type_does_not_block_async_instance():
@Promise.safe
def do():
def do_resolve(x):
return x
a_loader, a_load_calls = id_loader(resolve=do_resolve)
with raises(Exception):
a_loader.load("A1").get()
assert async_instance.have_drained_queues
with raises(Exception):
a_loader.load("A2").get()
assert async_instance.have_drained_queues
do().get()
|
