1
00:00:00,480 --> 00:00:03,480
foreign

2
00:00:10,880 --> 00:00:15,719
is an independent independent software

3
00:00:13,620 --> 00:00:18,300
consultant building python-based

4
00:00:15,719 --> 00:00:20,039
back-end devops and Data Systems she

5
00:00:18,300 --> 00:00:22,500
also teaches python via online

6
00:00:20,039 --> 00:00:24,539
month-long boot camps she's an open

7
00:00:22,500 --> 00:00:27,359
source Enthusiast and has contributed to

8
00:00:24,539 --> 00:00:30,980
pandas and Apache airflow please put

9
00:00:27,359 --> 00:00:30,980
your hands together for povani

10
00:00:32,120 --> 00:00:35,940
thank you

11
00:00:34,079 --> 00:00:40,340
thank you thanks for such a nice

12
00:00:35,940 --> 00:00:43,020
introduction first of all hello everyone

13
00:00:40,340 --> 00:00:45,719
hello everyone

14
00:00:43,020 --> 00:00:49,200
okay nice good now we are all awake I

15
00:00:45,719 --> 00:00:51,000
know we are hungry but

16
00:00:49,200 --> 00:00:53,160
just to put things into perspective I'm

17
00:00:51,000 --> 00:00:55,440
bhavani Ravi I've been fallen in love by

18
00:00:53,160 --> 00:00:57,660
with python seven years back and it's

19
00:00:55,440 --> 00:00:59,640
still going on I'm an independent

20
00:00:57,660 --> 00:01:01,920
software consultant I get thrown into

21
00:00:59,640 --> 00:01:04,680
technical problems and I Rise Up from

22
00:01:01,920 --> 00:01:07,320
there that's what I do for living

23
00:01:04,680 --> 00:01:09,180
and today we are here to build our own

24
00:01:07,320 --> 00:01:12,299
unit testing Library

25
00:01:09,180 --> 00:01:14,280
and when I put out this talk and tell to

26
00:01:12,299 --> 00:01:18,540
all my friends that the talkers accepted

27
00:01:14,280 --> 00:01:19,560
the very first question was why

28
00:01:18,540 --> 00:01:22,140
Center

29
00:01:19,560 --> 00:01:23,460
why even your own testing Library

30
00:01:22,140 --> 00:01:25,740
and

31
00:01:23,460 --> 00:01:30,500
I don't have a perfect answer for that I

32
00:01:25,740 --> 00:01:30,500
have an answer for that one is it's fun

33
00:01:30,840 --> 00:01:34,799
remember when you all first started

34
00:01:33,240 --> 00:01:36,780
programming remember that moment when

35
00:01:34,799 --> 00:01:38,520
you've fallen in love with that first

36
00:01:36,780 --> 00:01:41,820
program that you wrote it gave you that

37
00:01:38,520 --> 00:01:44,820
spark and kept you hooked all along mine

38
00:01:41,820 --> 00:01:46,799
was printing the first 10 numbers and I

39
00:01:44,820 --> 00:01:49,619
changed the program to ten thousand and

40
00:01:46,799 --> 00:01:52,500
then to a lakh until the system crashed

41
00:01:49,619 --> 00:01:55,619
but there came a point where programs

42
00:01:52,500 --> 00:01:58,320
like that got really boring and now I

43
00:01:55,619 --> 00:01:59,340
can do this for fun and I hope you can

44
00:01:58,320 --> 00:02:01,380
too

45
00:01:59,340 --> 00:02:03,180
and there's this Rich environments quote

46
00:02:01,380 --> 00:02:05,820
what you don't create you don't

47
00:02:03,180 --> 00:02:06,960
understand and I pretty much love this

48
00:02:05,820 --> 00:02:09,420
quote

49
00:02:06,960 --> 00:02:11,819
and as a result of that I created own

50
00:02:09,420 --> 00:02:15,180
flask my own version of flask

51
00:02:11,819 --> 00:02:16,220
application and that was almost a year

52
00:02:15,180 --> 00:02:19,260
back

53
00:02:16,220 --> 00:02:22,739
it's been too long since I've had fun so

54
00:02:19,260 --> 00:02:25,980
now I am after Pi test

55
00:02:22,739 --> 00:02:27,440
the only problem was I've been using pi

56
00:02:25,980 --> 00:02:30,480
test pretty much

57
00:02:27,440 --> 00:02:31,920
extensively the last uh eight months and

58
00:02:30,480 --> 00:02:34,140
the hundred percent test coverage from

59
00:02:31,920 --> 00:02:36,239
the previous talk all of that was so

60
00:02:34,140 --> 00:02:38,280
relatable and I love all of these

61
00:02:36,239 --> 00:02:40,620
features that by test provides the test

62
00:02:38,280 --> 00:02:42,959
Runner parameterized test cases expected

63
00:02:40,620 --> 00:02:45,300
exceptions fixtures mocking you name

64
00:02:42,959 --> 00:02:46,640
them I use them

65
00:02:45,300 --> 00:02:49,080
and

66
00:02:46,640 --> 00:02:50,519
show all fans how many of you have used

67
00:02:49,080 --> 00:02:52,920
by test

68
00:02:50,519 --> 00:02:55,019
okay everybody almost everybody if you

69
00:02:52,920 --> 00:02:57,360
have not used it your logic will look

70
00:02:55,019 --> 00:02:59,640
something like this and your Associated

71
00:02:57,360 --> 00:03:02,099
test case which starts with test

72
00:02:59,640 --> 00:03:04,920
underscore followed by you call your

73
00:03:02,099 --> 00:03:07,080
logic and test whether that uh that the

74
00:03:04,920 --> 00:03:09,000
logic behaves the exact same way and

75
00:03:07,080 --> 00:03:10,800
that's a very simple test case this is

76
00:03:09,000 --> 00:03:14,459
your parameterized test case where you

77
00:03:10,800 --> 00:03:16,319
pass a bunch of data and hope that all

78
00:03:14,459 --> 00:03:17,580
the data that you're passing behave the

79
00:03:16,319 --> 00:03:19,860
same way as well

80
00:03:17,580 --> 00:03:21,360
and you can also expect your

81
00:03:19,860 --> 00:03:24,780
functionality to raise a particular

82
00:03:21,360 --> 00:03:26,879
exception and a pie test will capture

83
00:03:24,780 --> 00:03:29,519
that

84
00:03:26,879 --> 00:03:33,060
so I thought okay let's start building

85
00:03:29,519 --> 00:03:35,640
it and the first place to start is

86
00:03:33,060 --> 00:03:38,700
reverse engineer it and I went and

87
00:03:35,640 --> 00:03:41,280
looked into Pi test source code and this

88
00:03:38,700 --> 00:03:42,360
was the reaction

89
00:03:41,280 --> 00:03:43,920
I

90
00:03:42,360 --> 00:03:47,580
well

91
00:03:43,920 --> 00:03:51,540
it has about 130k lines of code

92
00:03:47,580 --> 00:03:53,819
earliest comment was on 2007 and so far

93
00:03:51,540 --> 00:03:55,920
there are 5000 PRS being merged for the

94
00:03:53,819 --> 00:03:58,319
project which is a lot more than flask

95
00:03:55,920 --> 00:04:00,180
flask was very rather simple what I'm

96
00:03:58,319 --> 00:04:02,540
trying to say with all this is It's hard

97
00:04:00,180 --> 00:04:06,120
to reverse and generate

98
00:04:02,540 --> 00:04:08,400
the next option was chargpt or GitHub

99
00:04:06,120 --> 00:04:11,640
co-pilot because we are all relying on

100
00:04:08,400 --> 00:04:13,080
that so much but things like this llms

101
00:04:11,640 --> 00:04:16,199
really work if there are previous

102
00:04:13,080 --> 00:04:17,820
examples available unfortunately even if

103
00:04:16,199 --> 00:04:19,079
you Google right now there are not a lot

104
00:04:17,820 --> 00:04:21,060
of examples on how do you build a

105
00:04:19,079 --> 00:04:24,479
listing library from scratch

106
00:04:21,060 --> 00:04:25,440
so again thrown out of all the options

107
00:04:24,479 --> 00:04:26,460
here

108
00:04:25,440 --> 00:04:28,759
so

109
00:04:26,460 --> 00:04:31,259
building my own testing Library

110
00:04:28,759 --> 00:04:33,120
reflecting whatever Pi test provides as

111
00:04:31,259 --> 00:04:36,960
an interface I'm gonna have all these

112
00:04:33,120 --> 00:04:39,240
features and let's see how that goes

113
00:04:36,960 --> 00:04:41,160
first starting with the test Runner I'm

114
00:04:39,240 --> 00:04:43,979
going to be live coding this and if I

115
00:04:41,160 --> 00:04:47,160
make any mistakes please be kind to me

116
00:04:43,979 --> 00:04:50,160
and the test Runner this is all our

117
00:04:47,160 --> 00:04:52,500
version this is not by this version so

118
00:04:50,160 --> 00:04:56,040
it has an interface that looks like this

119
00:04:52,500 --> 00:04:58,560
you do PI test followed by the directory

120
00:04:56,040 --> 00:05:00,120
that you want to test and if we think

121
00:04:58,560 --> 00:05:01,440
about it how would you write a test

122
00:05:00,120 --> 00:05:04,380
Runner

123
00:05:01,440 --> 00:05:06,660
first problem is finding out all the

124
00:05:04,380 --> 00:05:08,520
test functions that are there in all the

125
00:05:06,660 --> 00:05:12,180
test files under that for the particular

126
00:05:08,520 --> 00:05:15,120
directory and then you have to run them

127
00:05:12,180 --> 00:05:17,280
maintain a streak of success and failure

128
00:05:15,120 --> 00:05:20,220
and if there is an error you have to

129
00:05:17,280 --> 00:05:21,540
report them can we live code it

130
00:05:20,220 --> 00:05:23,880
okay

131
00:05:21,540 --> 00:05:26,220
I did say we are going to do things from

132
00:05:23,880 --> 00:05:28,380
scratch but I kind of lied

133
00:05:26,220 --> 00:05:31,440
so we're gonna

134
00:05:28,380 --> 00:05:33,720
start with this so here's my test

135
00:05:31,440 --> 00:05:36,660
function okay

136
00:05:33,720 --> 00:05:39,840
here's my own test module which is where

137
00:05:36,660 --> 00:05:41,220
we're gonna fill out things uh the test

138
00:05:39,840 --> 00:05:44,160
Runner is the only thing that's going to

139
00:05:41,220 --> 00:05:46,560
run everything else is a race an

140
00:05:44,160 --> 00:05:48,120
accepted reception parameterize picture

141
00:05:46,560 --> 00:05:51,180
which we will come back and fill in

142
00:05:48,120 --> 00:05:52,919
later here is my test Runner and some of

143
00:05:51,180 --> 00:05:56,340
the complex complexities I have written

144
00:05:52,919 --> 00:05:59,820
away using certain functions so

145
00:05:56,340 --> 00:06:02,699
I have got all the test files I've got

146
00:05:59,820 --> 00:06:04,800
all the test objects here and the only

147
00:06:02,699 --> 00:06:07,919
thing that we have to do right now is

148
00:06:04,800 --> 00:06:11,060
run the test cases so what do we mean

149
00:06:07,919 --> 00:06:11,060
when we run the test case

150
00:06:15,780 --> 00:06:20,580
we have a test uh sorry we have a test

151
00:06:18,419 --> 00:06:22,800
file with a bunch of functions we have

152
00:06:20,580 --> 00:06:24,600
loaded all that function into our module

153
00:06:22,800 --> 00:06:26,580
now we have the test function name and

154
00:06:24,600 --> 00:06:29,580
the test function object and running

155
00:06:26,580 --> 00:06:33,479
would running them would actually mean

156
00:06:29,580 --> 00:06:36,259
calling that test function object and if

157
00:06:33,479 --> 00:06:36,259
I run this

158
00:06:36,780 --> 00:06:41,520
so I'm going to use the own Pi test

159
00:06:39,000 --> 00:06:43,440
module and pass all the test cases all

160
00:06:41,520 --> 00:06:44,940
this functionality of reading the

161
00:06:43,440 --> 00:06:48,539
directory reading all the functions has

162
00:06:44,940 --> 00:06:50,940
been already written so if I run this it

163
00:06:48,539 --> 00:06:53,520
says success no address has been found

164
00:06:50,940 --> 00:06:55,680
whether it's really working or not I

165
00:06:53,520 --> 00:06:58,680
might not know so what I'm gonna do is

166
00:06:55,680 --> 00:07:00,600
in my case I'm going to make it 10 and

167
00:06:58,680 --> 00:07:03,020
see what happens

168
00:07:00,600 --> 00:07:03,020
okay

169
00:07:03,060 --> 00:07:07,020
there we have it our first assertion

170
00:07:05,100 --> 00:07:08,880
error so it's not just a matter of

171
00:07:07,020 --> 00:07:10,680
calling the function to run the test

172
00:07:08,880 --> 00:07:12,120
case you have to also maintain a streak

173
00:07:10,680 --> 00:07:13,560
of all your errors

174
00:07:12,120 --> 00:07:16,500
so

175
00:07:13,560 --> 00:07:18,740
let's wrap this in a very nice try and

176
00:07:16,500 --> 00:07:18,740
accept

177
00:07:25,500 --> 00:07:31,020
all right so we're gonna wrap it in a

178
00:07:27,660 --> 00:07:33,900
nice except and there we go so we're

179
00:07:31,020 --> 00:07:36,720
gonna keep a track of our exception

180
00:07:33,900 --> 00:07:39,180
and under here if there are any errors

181
00:07:36,720 --> 00:07:40,860
we have to print them so let's print it

182
00:07:39,180 --> 00:07:46,340
for

183
00:07:40,860 --> 00:07:46,340
wow life coding is hard so here we go

184
00:07:46,740 --> 00:07:50,819
I'm kind of cheating right here but it's

185
00:07:48,900 --> 00:07:52,860
okay so we are capturing all the errors

186
00:07:50,819 --> 00:07:55,460
we are getting a trace back and we're

187
00:07:52,860 --> 00:07:55,460
printing them

188
00:07:56,340 --> 00:07:59,160
hmm

189
00:07:57,720 --> 00:08:01,080
so okay

190
00:07:59,160 --> 00:08:03,599
we have something running here and then

191
00:08:01,080 --> 00:08:05,099
there is an error under test ad these

192
00:08:03,599 --> 00:08:07,080
are the this is a trace bag and where

193
00:08:05,099 --> 00:08:09,660
the session error is happening let's

194
00:08:07,080 --> 00:08:11,759
also give some more meaningful things so

195
00:08:09,660 --> 00:08:15,620
that we know something is running

196
00:08:11,759 --> 00:08:15,620
running desk keys

197
00:08:16,500 --> 00:08:20,639
test function name

198
00:08:18,060 --> 00:08:22,860
all right so we know that it's running

199
00:08:20,639 --> 00:08:26,099
certain test cases there are certain

200
00:08:22,860 --> 00:08:29,759
errors let's revert the spark that's our

201
00:08:26,099 --> 00:08:32,039
test Runner so now we have a test Runner

202
00:08:29,759 --> 00:08:35,719
which takes all the text objects runs

203
00:08:32,039 --> 00:08:37,740
them marks them success marks them error

204
00:08:35,719 --> 00:08:40,380
we're good to go

205
00:08:37,740 --> 00:08:42,959
the next thing is the easiest one of all

206
00:08:40,380 --> 00:08:44,940
accepted exceptions so looking at this

207
00:08:42,959 --> 00:08:48,240
by test.racist we are going to implement

208
00:08:44,940 --> 00:08:51,200
the races what can you make out of it

209
00:08:48,240 --> 00:08:51,200
the interface

210
00:08:52,680 --> 00:08:58,680
races is a context manager

211
00:08:55,920 --> 00:09:01,680
and context managers if you have seen it

212
00:08:58,680 --> 00:09:04,140
it comes with an entry and an exit block

213
00:09:01,680 --> 00:09:06,120
it is initialized with an exception type

214
00:09:04,140 --> 00:09:09,540
that you're expecting

215
00:09:06,120 --> 00:09:11,100
and when exiting the block you have to

216
00:09:09,540 --> 00:09:13,380
ensure that the particular exception

217
00:09:11,100 --> 00:09:15,300
that you have mentioned should be raised

218
00:09:13,380 --> 00:09:16,740
and if not we are going to raise an

219
00:09:15,300 --> 00:09:17,940
assertion error

220
00:09:16,740 --> 00:09:20,880
and

221
00:09:17,940 --> 00:09:21,899
oops not here yet

222
00:09:20,880 --> 00:09:25,680
okay

223
00:09:21,899 --> 00:09:30,480
so let's go to our PI test.races own pi

224
00:09:25,680 --> 00:09:33,360
test.races and this is my template block

225
00:09:30,480 --> 00:09:36,480
so right now to test this particular

226
00:09:33,360 --> 00:09:38,339
aspect of it I have a very nicely

227
00:09:36,480 --> 00:09:40,440
written test case right here so this is

228
00:09:38,339 --> 00:09:43,680
going to address type error if I'm

229
00:09:40,440 --> 00:09:45,060
passing anything that's not a integer to

230
00:09:43,680 --> 00:09:47,399
my uh

231
00:09:45,060 --> 00:09:50,100
ad subtract multiple divide

232
00:09:47,399 --> 00:09:51,060
so let's run this now it raises a type

233
00:09:50,100 --> 00:09:53,040
error

234
00:09:51,060 --> 00:09:54,839
and it's not being captured it's not

235
00:09:53,040 --> 00:09:57,540
being handled because we haven't

236
00:09:54,839 --> 00:09:59,940
implemented this Rises yet if you've

237
00:09:57,540 --> 00:10:02,040
perfectly implemented it then it would

238
00:09:59,940 --> 00:10:04,019
just pass through and Mark everything as

239
00:10:02,040 --> 00:10:06,660
access because the function is working

240
00:10:04,019 --> 00:10:09,779
as expected so at enter we don't have to

241
00:10:06,660 --> 00:10:13,200
do anything at Exit we have to check

242
00:10:09,779 --> 00:10:15,959
if the first the exception type is none

243
00:10:13,200 --> 00:10:19,560
or not if it's none no exception has

244
00:10:15,959 --> 00:10:21,300
been raised so that is there and if the

245
00:10:19,560 --> 00:10:22,800
exception type is not there then we are

246
00:10:21,300 --> 00:10:24,779
raising an assertion error both the

247
00:10:22,800 --> 00:10:27,240
cases Association error different logic

248
00:10:24,779 --> 00:10:29,940
but how is GitHub copilot doing all that

249
00:10:27,240 --> 00:10:33,019
because I have practiced this almost 100

250
00:10:29,940 --> 00:10:35,459
times so far so

251
00:10:33,019 --> 00:10:37,260
assertion error raised when the

252
00:10:35,459 --> 00:10:41,220
exception type is none or if it's not

253
00:10:37,260 --> 00:10:43,459
matched so now let's run this

254
00:10:41,220 --> 00:10:45,779
okay that's weird

255
00:10:43,459 --> 00:10:49,680
since we have already handled the

256
00:10:45,779 --> 00:10:52,079
exception we also have to Market as true

257
00:10:49,680 --> 00:10:54,899
that you don't have to do anything just

258
00:10:52,079 --> 00:10:57,000
everything is nice and good

259
00:10:54,899 --> 00:11:00,120
so now it has ran the test cases it has

260
00:10:57,000 --> 00:11:02,040
also ran the test Rises and things are

261
00:11:00,120 --> 00:11:04,260
fine and well but

262
00:11:02,040 --> 00:11:06,600
is it really working well

263
00:11:04,260 --> 00:11:08,700
so instead of this zero division error I

264
00:11:06,600 --> 00:11:10,620
am going to mark it as typewriter as

265
00:11:08,700 --> 00:11:12,180
well now our function should fail

266
00:11:10,620 --> 00:11:14,399
because it's expecting something and

267
00:11:12,180 --> 00:11:16,680
resulting in something

268
00:11:14,399 --> 00:11:21,000
there we go we have an assertion error

269
00:11:16,680 --> 00:11:23,820
my yes raised typewriter has been raised

270
00:11:21,000 --> 00:11:26,040
instead of a zero division error so yeah

271
00:11:23,820 --> 00:11:29,540
kind of works there

272
00:11:26,040 --> 00:11:29,540
let's revert this back

273
00:11:30,420 --> 00:11:35,420
and life is all good nice and successful

274
00:11:33,180 --> 00:11:35,420
again

275
00:11:36,899 --> 00:11:40,200
good

276
00:11:38,160 --> 00:11:42,660
the next thing is parameterized test

277
00:11:40,200 --> 00:11:44,640
case again this isn't this this might

278
00:11:42,660 --> 00:11:46,320
look very difficult but it's also very

279
00:11:44,640 --> 00:11:48,079
simple

280
00:11:46,320 --> 00:11:50,040
or the drill looking at

281
00:11:48,079 --> 00:11:51,480
bytest.mark.paramel trials what can you

282
00:11:50,040 --> 00:11:54,980
make out of it

283
00:11:51,480 --> 00:11:54,980
what python construct it is

284
00:11:55,200 --> 00:12:00,000
a decorator and if you look at it it's

285
00:11:57,899 --> 00:12:03,360
not just a normal decorator it's a

286
00:12:00,000 --> 00:12:05,760
decorator with arguments oh scary

287
00:12:03,360 --> 00:12:08,399
when it's so first you are registering

288
00:12:05,760 --> 00:12:10,140
the parameters the second your uh you're

289
00:12:08,399 --> 00:12:12,000
registering the function and then you're

290
00:12:10,140 --> 00:12:14,279
gonna return a wrapper all of that has

291
00:12:12,000 --> 00:12:17,100
to happen

292
00:12:14,279 --> 00:12:19,140
and when once you have the function then

293
00:12:17,100 --> 00:12:21,540
the function is being called you have to

294
00:12:19,140 --> 00:12:22,920
run it n times so that all your subtest

295
00:12:21,540 --> 00:12:25,380
also runs

296
00:12:22,920 --> 00:12:27,540
and lock the results even if there is

297
00:12:25,380 --> 00:12:29,880
failure in either one of them you have

298
00:12:27,540 --> 00:12:33,180
to ensure that that is captured and

299
00:12:29,880 --> 00:12:38,360
finally you will get there

300
00:12:33,180 --> 00:12:38,360
so Pi tested parameterize here is my

301
00:12:38,540 --> 00:12:44,940
is going to fill it the keys are look

302
00:12:42,660 --> 00:12:47,220
okay first the test case the own tester

303
00:12:44,940 --> 00:12:49,500
parameterize looks something like this

304
00:12:47,220 --> 00:12:51,980
here I've used Python's eval don't ever

305
00:12:49,500 --> 00:12:53,820
use it in production

306
00:12:51,980 --> 00:12:56,940
and

307
00:12:53,820 --> 00:12:59,519
yeah so to the parameters I am passing

308
00:12:56,940 --> 00:13:01,800
like three four Arguments for me to test

309
00:12:59,519 --> 00:13:03,839
it and your keys are going to be this

310
00:13:01,800 --> 00:13:06,959
your values are going to be this first

311
00:13:03,839 --> 00:13:08,940
when registering the arguments I have to

312
00:13:06,959 --> 00:13:12,839
put it in a nice format so that I can

313
00:13:08,940 --> 00:13:14,220
just pass it as argument so let's make a

314
00:13:12,839 --> 00:13:18,600
test args

315
00:13:14,220 --> 00:13:20,940
list and here we are going to

316
00:13:18,600 --> 00:13:22,800
okay

317
00:13:20,940 --> 00:13:25,139
different than the previous one but sure

318
00:13:22,800 --> 00:13:26,459
next what we're going to do is we are

319
00:13:25,139 --> 00:13:27,660
going to when the function is being

320
00:13:26,459 --> 00:13:30,839
called when your test case is being

321
00:13:27,660 --> 00:13:36,139
called You're creating subtests so let's

322
00:13:30,839 --> 00:13:36,139
create I comma test ARG

323
00:13:36,860 --> 00:13:41,779
in numerate of test arguments

324
00:13:42,740 --> 00:13:47,839
then we'll print that we are running the

325
00:13:45,300 --> 00:13:47,839
subdes

326
00:13:50,399 --> 00:13:55,940
and also call the particular function

327
00:13:52,740 --> 00:13:55,940
with the test argument

328
00:13:55,980 --> 00:14:00,779
so when previously when we were calling

329
00:13:58,920 --> 00:14:02,700
the test function it was just calling

330
00:14:00,779 --> 00:14:04,740
that one particular test object right

331
00:14:02,700 --> 00:14:07,320
now what we are calling is the wrapped

332
00:14:04,740 --> 00:14:08,639
decorator so inside the lab tech Creator

333
00:14:07,320 --> 00:14:10,440
instead of directly calling the function

334
00:14:08,639 --> 00:14:12,060
we are calling the function n number of

335
00:14:10,440 --> 00:14:13,500
times based on the parameters that is

336
00:14:12,060 --> 00:14:14,639
getting registered

337
00:14:13,500 --> 00:14:17,040
so

338
00:14:14,639 --> 00:14:17,820
let's run this

339
00:14:17,040 --> 00:14:21,360
um

340
00:14:17,820 --> 00:14:23,880
yeah so you have running sub uh subtest

341
00:14:21,360 --> 00:14:25,800
0 1 2 depending on the parameters if I

342
00:14:23,880 --> 00:14:28,920
go and add more it's going to add more

343
00:14:25,800 --> 00:14:30,959
if I change something here that also

344
00:14:28,920 --> 00:14:33,720
gets handled because we have taken care

345
00:14:30,959 --> 00:14:35,040
of assertion errors globally not you

346
00:14:33,720 --> 00:14:37,160
have to do you don't have to do anything

347
00:14:35,040 --> 00:14:41,240
particularly inside the parameterization

348
00:14:37,160 --> 00:14:41,240
so that is also good

349
00:14:41,399 --> 00:14:44,399
great

350
00:14:45,600 --> 00:14:50,880
all good now

351
00:14:48,480 --> 00:14:53,940
we have a decorator that takes arguments

352
00:14:50,880 --> 00:14:54,899
and a function looped over it all good

353
00:14:53,940 --> 00:14:58,500
to go

354
00:14:54,899 --> 00:15:00,720
the last but the scary part is fixtures

355
00:14:58,500 --> 00:15:03,600
this is a scary thing for me very easy

356
00:15:00,720 --> 00:15:04,620
to use very nice feature of Pi test but

357
00:15:03,600 --> 00:15:06,240
this one

358
00:15:04,620 --> 00:15:08,519
suck my brain out because I have to

359
00:15:06,240 --> 00:15:10,980
implement it all by myself

360
00:15:08,519 --> 00:15:13,440
and fixtures are great because you can

361
00:15:10,980 --> 00:15:16,500
do a ton of things from there

362
00:15:13,440 --> 00:15:19,260
you can define a whole large data set

363
00:15:16,500 --> 00:15:21,839
and have it available and multiple tests

364
00:15:19,260 --> 00:15:24,000
can use it or you can do your setup and

365
00:15:21,839 --> 00:15:25,620
tear down and there are Pi test comes

366
00:15:24,000 --> 00:15:28,980
with enormous amount of features this or

367
00:15:25,620 --> 00:15:31,800
to use scoping you can put it in your

368
00:15:28,980 --> 00:15:34,260
conf test and the variety no wonder they

369
00:15:31,800 --> 00:15:37,079
have 130k lines right they want to make

370
00:15:34,260 --> 00:15:39,180
your life easier so

371
00:15:37,079 --> 00:15:41,940
it's a decorator again

372
00:15:39,180 --> 00:15:43,079
and you can register a function as a

373
00:15:41,940 --> 00:15:46,139
fixture

374
00:15:43,079 --> 00:15:49,680
and when you are running the test case

375
00:15:46,139 --> 00:15:52,139
you have to ensure that you are passing

376
00:15:49,680 --> 00:15:55,680
the argument which is a fixture which in

377
00:15:52,139 --> 00:15:58,560
turn is a function which is decorated

378
00:15:55,680 --> 00:16:01,920
appeared yeah that's how I felt too

379
00:15:58,560 --> 00:16:04,800
handling test argument that is a fixture

380
00:16:01,920 --> 00:16:06,839
and then you have fixtures that are just

381
00:16:04,800 --> 00:16:09,660
data fixtures which is going to return

382
00:16:06,839 --> 00:16:11,160
dictionary or a list or a tuple or you

383
00:16:09,660 --> 00:16:14,160
have yielding fixtures which is going to

384
00:16:11,160 --> 00:16:16,139
yield and then do something later so all

385
00:16:14,160 --> 00:16:19,639
of these things are going on

386
00:16:16,139 --> 00:16:19,639
let's try to implement this

387
00:16:23,220 --> 00:16:28,500
so here is our beautiful fixture

388
00:16:26,519 --> 00:16:30,240
and that's it

389
00:16:28,500 --> 00:16:31,980
that's all you have to do for fixtures

390
00:16:30,240 --> 00:16:35,220
because

391
00:16:31,980 --> 00:16:38,100
you register a function as a fixture and

392
00:16:35,220 --> 00:16:39,899
your job is done but a lot of things

393
00:16:38,100 --> 00:16:43,079
that you have to do is in your test

394
00:16:39,899 --> 00:16:45,000
Runner you have to ensure that you are

395
00:16:43,079 --> 00:16:47,040
passing the arguments so far when we are

396
00:16:45,000 --> 00:16:49,980
calling the test function we are not

397
00:16:47,040 --> 00:16:52,500
passing any arguments so first thing

398
00:16:49,980 --> 00:16:55,800
that we have to do is to find out what

399
00:16:52,500 --> 00:17:00,060
arguments like parameters are there

400
00:16:55,800 --> 00:17:03,120
in your test function so this particular

401
00:17:00,060 --> 00:17:05,220
construct code variable names will give

402
00:17:03,120 --> 00:17:09,959
you all the arguments of a particular

403
00:17:05,220 --> 00:17:11,760
function and for args in test args we

404
00:17:09,959 --> 00:17:14,459
have to see whether that particular

405
00:17:11,760 --> 00:17:16,199
picture is in a fiction mapping

406
00:17:14,459 --> 00:17:18,959
but we haven't defined our fiction

407
00:17:16,199 --> 00:17:20,640
mapping yet so let's go to that here I

408
00:17:18,959 --> 00:17:23,459
have some logic to get all the test

409
00:17:20,640 --> 00:17:25,260
functions this does nothing but get all

410
00:17:23,459 --> 00:17:27,299
the members of the module

411
00:17:25,260 --> 00:17:29,520
finds out all the functions that starts

412
00:17:27,299 --> 00:17:32,880
with test underscore this time we are

413
00:17:29,520 --> 00:17:34,440
also going to check if members of one

414
00:17:32,880 --> 00:17:37,400
which is the object

415
00:17:34,440 --> 00:17:37,400
Dot

416
00:17:39,660 --> 00:17:43,799
name is a fixture wrapper because we

417
00:17:41,880 --> 00:17:45,480
have wrapped it in a fixture then we are

418
00:17:43,799 --> 00:17:48,419
going to store it in the fixture app

419
00:17:45,480 --> 00:17:51,419
picture mapping so great

420
00:17:48,419 --> 00:17:54,660
so it's in the fixture mapping then you

421
00:17:51,419 --> 00:17:56,880
call it that is your test argument

422
00:17:54,660 --> 00:17:58,919
let's also create a list

423
00:17:56,880 --> 00:18:01,080
of course this code is never going to be

424
00:17:58,919 --> 00:18:03,179
used or being production so all the

425
00:18:01,080 --> 00:18:05,419
solid yagni principles doesn't apply

426
00:18:03,179 --> 00:18:05,419
here

427
00:18:05,520 --> 00:18:08,179
list

428
00:18:08,460 --> 00:18:13,559
all right we are not going to use it

429
00:18:11,940 --> 00:18:15,900
test

430
00:18:13,559 --> 00:18:18,240
s

431
00:18:15,900 --> 00:18:21,720
dot append we are going to call the

432
00:18:18,240 --> 00:18:23,940
fixture and get the result put it in a

433
00:18:21,720 --> 00:18:27,000
test art list

434
00:18:23,940 --> 00:18:30,120
and gonna pass it to

435
00:18:27,000 --> 00:18:31,380
desktop list now when I run this it's

436
00:18:30,120 --> 00:18:34,200
gonna pass

437
00:18:31,380 --> 00:18:35,400
let's uncomment these test cases here I

438
00:18:34,200 --> 00:18:38,820
have a fixture that is getting

439
00:18:35,400 --> 00:18:41,640
registered and we have a

440
00:18:38,820 --> 00:18:42,720
a test con which is going to execute a

441
00:18:41,640 --> 00:18:43,980
particular connection which is also

442
00:18:42,720 --> 00:18:48,179
going to raise an operational error

443
00:18:43,980 --> 00:18:49,380
because I don't even have the database

444
00:18:48,179 --> 00:18:51,660
don't

445
00:18:49,380 --> 00:18:53,580
it's raising an assertion error which is

446
00:18:51,660 --> 00:18:56,580
weird because

447
00:18:53,580 --> 00:18:58,320
it's expecting an operational error but

448
00:18:56,580 --> 00:19:01,440
it's actually getting an attribute error

449
00:18:58,320 --> 00:19:04,020
what do you think is happening here

450
00:19:01,440 --> 00:19:06,660
Beyond errors like that has popped up

451
00:19:04,020 --> 00:19:09,720
and the problem is because of what's

452
00:19:06,660 --> 00:19:11,400
happening in con fixture if we go go

453
00:19:09,720 --> 00:19:12,840
here and print out what is actually

454
00:19:11,400 --> 00:19:15,299
getting passed when we are running the

455
00:19:12,840 --> 00:19:17,340
test case is you can see that it's a

456
00:19:15,299 --> 00:19:19,679
generator this is where I said it's an

457
00:19:17,340 --> 00:19:22,500
yielding function not

458
00:19:19,679 --> 00:19:24,419
a direct data fixture so we have to do

459
00:19:22,500 --> 00:19:25,860
something even more crazy

460
00:19:24,419 --> 00:19:28,559
uh

461
00:19:25,860 --> 00:19:30,660
again back to our test Runner here we

462
00:19:28,559 --> 00:19:32,780
have an argument which is the fixture we

463
00:19:30,660 --> 00:19:36,500
know that great

464
00:19:32,780 --> 00:19:36,500
now we have to get

465
00:19:39,480 --> 00:19:45,360
let's get the fixture object

466
00:19:42,960 --> 00:19:48,440
and we have to check if the fixture

467
00:19:45,360 --> 00:19:48,440
object has

468
00:19:49,440 --> 00:19:55,740
the next argument in it so that we know

469
00:19:52,799 --> 00:19:59,039
it's a yielding gen it's a generator if

470
00:19:55,740 --> 00:20:01,380
it's a generator we are going to call it

471
00:19:59,039 --> 00:20:03,480
and then store that value

472
00:20:01,380 --> 00:20:05,940
else

473
00:20:03,480 --> 00:20:09,780
we're going to call that object directly

474
00:20:05,940 --> 00:20:11,760
so that's the logic

475
00:20:09,780 --> 00:20:13,559
there are two types of fixtures one is

476
00:20:11,760 --> 00:20:16,559
an yielding fixture which is a generator

477
00:20:13,559 --> 00:20:19,020
the other one is a direct fixture object

478
00:20:16,559 --> 00:20:20,640
which just passes the data and we have

479
00:20:19,020 --> 00:20:22,260
handled both the cases now let's run

480
00:20:20,640 --> 00:20:24,240
this

481
00:20:22,260 --> 00:20:26,760
oh still an assertion error this has

482
00:20:24,240 --> 00:20:29,100
also happened quite a bit of time and

483
00:20:26,760 --> 00:20:32,160
still legit

484
00:20:29,100 --> 00:20:34,799
it's still a generator object

485
00:20:32,160 --> 00:20:37,520
now I'm confused

486
00:20:34,799 --> 00:20:37,520
any help

487
00:20:38,940 --> 00:20:45,620
I didn't call it yes great

488
00:20:42,299 --> 00:20:45,620
oh I don't call

489
00:20:50,160 --> 00:20:52,700
hmm

490
00:20:57,360 --> 00:21:00,500
it's a fixture object

491
00:21:04,080 --> 00:21:08,580
we're calling it and then

492
00:21:06,780 --> 00:21:11,480
okay this is why I was scared of doing

493
00:21:08,580 --> 00:21:11,480
this but

494
00:21:14,340 --> 00:21:20,660
okay I'm gonna add more print statements

495
00:21:16,320 --> 00:21:20,660
very classic programmer move

496
00:21:21,660 --> 00:21:26,299
a picture object what is coming here

497
00:21:23,400 --> 00:21:26,299
it's a wrapper

498
00:21:30,780 --> 00:21:33,380
right

499
00:21:38,159 --> 00:21:43,799
okay I'm gonna pull out another classic

500
00:21:41,100 --> 00:21:46,860
programmer move is have your backup code

501
00:21:43,799 --> 00:21:49,980
go through that see what it does and

502
00:21:46,860 --> 00:21:51,600
just go with it so here is my perfectly

503
00:21:49,980 --> 00:21:55,400
running fixture

504
00:21:51,600 --> 00:21:55,400
stuff I'm gonna copy paste that

505
00:21:56,520 --> 00:22:02,580
all right so

506
00:21:59,940 --> 00:22:04,440
we have the fixture value here we are

507
00:22:02,580 --> 00:22:07,559
going to call return on it or you're

508
00:22:04,440 --> 00:22:10,760
gonna directly call next on it or just

509
00:22:07,559 --> 00:22:10,760
gonna directly append it

510
00:22:11,640 --> 00:22:14,480
so that's there

511
00:22:15,179 --> 00:22:20,720
perfectly out of sync okay much better

512
00:22:24,120 --> 00:22:28,820
still a lot of things test arcs to pass

513
00:22:32,220 --> 00:22:35,059
all right

514
00:22:38,820 --> 00:22:46,320
thank you so yes that is our fixture

515
00:22:43,020 --> 00:22:48,360
which is a healing fixture next we call

516
00:22:46,320 --> 00:22:49,740
next on it if not if it's a data fixture

517
00:22:48,360 --> 00:22:52,799
that will also work

518
00:22:49,740 --> 00:22:54,120
so after a very so thank you for that I

519
00:22:52,799 --> 00:22:55,080
didn't I forgot to put the thumbs up

520
00:22:54,120 --> 00:22:57,059
over here

521
00:22:55,080 --> 00:22:59,100
so if you want to go through the same

522
00:22:57,059 --> 00:23:01,080
thing you can you can go to my GitHub

523
00:22:59,100 --> 00:23:03,000
repository and try it out on your own

524
00:23:01,080 --> 00:23:05,340
there is a blog post associated with it

525
00:23:03,000 --> 00:23:07,760
with it which needs an update since a

526
00:23:05,340 --> 00:23:11,700
lot has changed in the last three months

527
00:23:07,760 --> 00:23:13,440
and what can you do to have fun is you

528
00:23:11,700 --> 00:23:16,320
can try implementing mocks on top of

529
00:23:13,440 --> 00:23:19,020
this or try testing this testing library

530
00:23:16,320 --> 00:23:21,539
or testing your own testing library or

531
00:23:19,020 --> 00:23:24,020
build your own eggs and have fun as a

532
00:23:21,539 --> 00:23:24,020
part of it

533
00:23:24,299 --> 00:23:29,039
yeah most importantly don't forgot the

534
00:23:27,299 --> 00:23:31,500
first program that you ever wrote which

535
00:23:29,039 --> 00:23:33,480
was very fun and kept you hooked so far

536
00:23:31,500 --> 00:23:35,159
and if you want to check out my other

537
00:23:33,480 --> 00:23:38,700
works here if you want to talk about

538
00:23:35,159 --> 00:23:41,580
python devops data data Ops I'm here

539
00:23:38,700 --> 00:23:43,700
thank you

540
00:23:41,580 --> 00:23:43,700
thank you

541
00:23:46,340 --> 00:23:50,360
we have some time for questions

542
00:23:51,720 --> 00:23:54,740
they're all too hungry

543
00:23:55,620 --> 00:23:58,940
oh just up there

544
00:24:08,460 --> 00:24:14,299
so I have a question regarding

545
00:24:11,340 --> 00:24:18,380
um once you have the test completed

546
00:24:14,299 --> 00:24:21,720
usually you end in a big trouble

547
00:24:18,380 --> 00:24:24,240
analyzing the test because usually you

548
00:24:21,720 --> 00:24:28,020
just need to look at the assertive

549
00:24:24,240 --> 00:24:30,299
statements but when things grow

550
00:24:28,020 --> 00:24:33,900
a bunch of things you have hundreds of

551
00:24:30,299 --> 00:24:37,020
tests and analyzing that is quite

552
00:24:33,900 --> 00:24:39,900
difficult so did you have any strategy

553
00:24:37,020 --> 00:24:43,159
once you have everything completed just

554
00:24:39,900 --> 00:24:45,799
for example instead of doing the assert

555
00:24:43,159 --> 00:24:48,720
racing specific

556
00:24:45,799 --> 00:24:51,500
assertions or custom exceptions do you

557
00:24:48,720 --> 00:24:51,500
have something in mind

558
00:24:53,220 --> 00:24:56,700
quite capture that question exactly what

559
00:24:55,679 --> 00:24:59,539
you

560
00:24:56,700 --> 00:25:02,640
when you are once the test is completed

561
00:24:59,539 --> 00:25:06,120
and the analysis of the test is a bit

562
00:25:02,640 --> 00:25:07,159
difficult so do you have any strategy

563
00:25:06,120 --> 00:25:09,840
for that

564
00:25:07,159 --> 00:25:11,520
all right so assertions I don't know

565
00:25:09,840 --> 00:25:13,679
whether this is what you're asking but

566
00:25:11,520 --> 00:25:16,919
if you do it with by test this is a pi

567
00:25:13,679 --> 00:25:18,980
test version of test case that's here

568
00:25:16,919 --> 00:25:18,980
um

569
00:25:19,080 --> 00:25:24,059
yes so when you do it with pi test I'm

570
00:25:21,960 --> 00:25:26,220
going to change things over here yeah

571
00:25:24,059 --> 00:25:28,679
any number would work and I'm going to

572
00:25:26,220 --> 00:25:31,559
run it with by test

573
00:25:28,679 --> 00:25:33,299
I have printed it pretty badly right

574
00:25:31,559 --> 00:25:34,980
because we are building it live but when

575
00:25:33,299 --> 00:25:37,080
you do it with whiteest it's gonna show

576
00:25:34,980 --> 00:25:39,900
you exactly where that error happens and

577
00:25:37,080 --> 00:25:41,940
it also has a very nice Trace back that

578
00:25:39,900 --> 00:25:44,580
you can print with more verbose things

579
00:25:41,940 --> 00:25:46,860
so it doesn't matter at what level the

580
00:25:44,580 --> 00:25:48,720
error occurs you will have a complete

581
00:25:46,860 --> 00:25:51,480
race back of things and there are

582
00:25:48,720 --> 00:25:53,220
options in pi test to do that I think I

583
00:25:51,480 --> 00:25:54,659
when we do this case it's just an

584
00:25:53,220 --> 00:25:56,279
assertion error happening at that

585
00:25:54,659 --> 00:25:58,799
particular line but if you have it in

586
00:25:56,279 --> 00:26:01,740
your logic there also it works so let's

587
00:25:58,799 --> 00:26:06,380
say you are expecting five here but

588
00:26:01,740 --> 00:26:06,380
instead of add I'm gonna change this to

589
00:26:06,600 --> 00:26:10,860
oh

590
00:26:08,159 --> 00:26:12,659
let's do something fun

591
00:26:10,860 --> 00:26:14,580
10 always

592
00:26:12,659 --> 00:26:17,360
then it's also going to give you that

593
00:26:14,580 --> 00:26:17,360
whole Trace back

594
00:26:17,400 --> 00:26:22,500
yeah so here it says you know assert on

595
00:26:19,740 --> 00:26:24,120
the left you get 10 but on the 5 uh if

596
00:26:22,500 --> 00:26:26,340
you're making any particular logical

597
00:26:24,120 --> 00:26:30,679
error that also comes as a part of the

598
00:26:26,340 --> 00:26:30,679
price back okay thank you very much

599
00:26:32,460 --> 00:26:35,240
um no other questions

600
00:26:38,520 --> 00:26:40,580
thank you

601
00:26:46,400 --> 00:26:49,799
what do you think is the most useful

602
00:26:48,240 --> 00:26:51,779
Insight you've got about the internals

603
00:26:49,799 --> 00:26:53,580
of Pi test that you learn from this

604
00:26:51,779 --> 00:26:54,840
re-implementation is there some part of

605
00:26:53,580 --> 00:26:57,620
the internals that you know you wish

606
00:26:54,840 --> 00:26:57,620
people better understood

607
00:26:58,500 --> 00:27:05,299
oops

608
00:27:01,080 --> 00:27:05,299
I'm gonna go back to the slide where

609
00:27:07,740 --> 00:27:14,820
I was pretty overwhelmed scared uh it

610
00:27:10,980 --> 00:27:17,520
was very hard to even just look at it or

611
00:27:14,820 --> 00:27:19,559
understand it because it has built for

612
00:27:17,520 --> 00:27:22,080
so many different use cases even

613
00:27:19,559 --> 00:27:23,700
something as simple as fixture it

614
00:27:22,080 --> 00:27:25,860
behaves completely differently to what

615
00:27:23,700 --> 00:27:28,260
we what I have built so I have stopped

616
00:27:25,860 --> 00:27:30,059
drawing inspiration from pie test way

617
00:27:28,260 --> 00:27:34,580
early in the process and just built up

618
00:27:30,059 --> 00:27:34,580
my own version so that's

619
00:27:38,700 --> 00:27:41,240
hmm

620
00:27:52,559 --> 00:27:57,120
thank you for your talk could you talk

621
00:27:54,840 --> 00:27:59,940
us through the entry point of your code

622
00:27:57,120 --> 00:28:02,700
how it iterates over the test files

623
00:27:59,940 --> 00:28:05,460
finds the test classes finds the test

624
00:28:02,700 --> 00:28:09,740
methods and then works out what to run

625
00:28:05,460 --> 00:28:09,740
sure so it's pretty

626
00:28:09,779 --> 00:28:12,840
but sure

627
00:28:11,279 --> 00:28:15,120
all right

628
00:28:12,840 --> 00:28:17,940
that's my test Runner and it gets test

629
00:28:15,120 --> 00:28:23,059
files and then a bunch of test functions

630
00:28:17,940 --> 00:28:23,059
so test files is nothing but reading

631
00:28:24,059 --> 00:28:28,980
reading the directory if the directory

632
00:28:27,000 --> 00:28:31,880
does not have test in it you skip the

633
00:28:28,980 --> 00:28:34,679
directory and if it does have in it

634
00:28:31,880 --> 00:28:37,380
check get all the files that starts with

635
00:28:34,679 --> 00:28:38,640
tests and ends with pi and then return

636
00:28:37,380 --> 00:28:41,400
them

637
00:28:38,640 --> 00:28:43,140
so that's all the test files inside any

638
00:28:41,400 --> 00:28:45,840
particular directory of course I have

639
00:28:43,140 --> 00:28:48,539
done it for only one level

640
00:28:45,840 --> 00:28:51,059
and for the test function I'm importing

641
00:28:48,539 --> 00:28:53,400
the whole module like the whole file and

642
00:28:51,059 --> 00:28:56,039
going through its members using whether

643
00:28:53,400 --> 00:28:57,419
it's it's a function and if it if a

644
00:28:56,039 --> 00:28:59,279
function starts with test underscore

645
00:28:57,419 --> 00:29:01,640
that is a test function and I'm passing

646
00:28:59,279 --> 00:29:01,640
them back

647
00:29:04,980 --> 00:29:08,360
that's that help

648
00:29:08,460 --> 00:29:13,620
thank you

649
00:29:10,799 --> 00:29:15,360
okay thank you um thanks pavani for such

650
00:29:13,620 --> 00:29:17,419
an engaging talk

651
00:29:15,360 --> 00:29:17,419
um

652
00:29:18,600 --> 00:29:23,179
it's a token of our appreciation thank

653
00:29:20,340 --> 00:29:23,179
you thank you

654
00:29:27,020 --> 00:29:32,940
uh one small thing a very thank you to

655
00:29:30,179 --> 00:29:34,679
pycon Au they have sponsored me to come

656
00:29:32,940 --> 00:29:36,720
all the way from India to present the

657
00:29:34,679 --> 00:29:39,440
stock here thank you so much from the

658
00:29:36,720 --> 00:29:39,440
bottom of my heart