-
Notifications
You must be signed in to change notification settings - Fork 0
/
essential-pytest-2.html
750 lines (680 loc) · 41.7 KB
/
essential-pytest-2.html
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
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1" />
<meta name="description" content="" />
<meta name="author" content="Simon Larsén" />
<meta name="generator" content="Pelican (VoidyBootstrap theme)" />
<title>Essential pytest pt. 2: Selecting tests to run - Programming for fun and profit</title>
<link rel="stylesheet"
href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css"
integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u"
crossorigin="anonymous" />
<link rel="stylesheet"
href="https://use.fontawesome.com/releases/v5.0.13/css/all.css"
integrity="sha384-DNOHZ68U8hZfKXOrtjWvjxusGo9WQnrNx2sqG0tfsghAvtVlRW3tvkXWZh58N9jp"
crossorigin="anonymous"
/>
<link rel="stylesheet" href="https://slar.se/theme/css/dracula.css" />
<link rel="stylesheet" href="https://slar.se/theme/css/voidybootstrap.css" />
<link rel="stylesheet" href="https://slar.se/theme/css/search.css" />
<link rel="shortcut icon" href="https://slar.se/favicon.ico" />
<link rel="stylesheet" href="https://files.stork-search.net/basic.css" /> <link href="https://slar.se/feeds/all.atom.xml" type="application/atom+xml" rel="alternate" title="Programming for fun and profit Atom Feed" />
</head>
<body>
<nav class="navbar navbar-default">
<div class="container">
<div class="navbar-header">
<button type="button" class="navbar-toggle"
data-toggle="collapse" data-target="#main-navbar-collapse">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="https://slar.se/" rel="home">
<i class="fas fa-home fa-fw fa-lg"> </i> </a>
</div>
<div class="collapse navbar-collapse" id="main-navbar-collapse">
<ul class="nav navbar-nav">
<li>
<a href="https://slar.se/pages/about.html">About</a>
</li>
<li>
<a href="https://slar.se/pages/publications-and-essays.html">Publications and Essays</a>
</li>
<li>
<a href="https://slar.se/pages/wiki.html">Wiki</a>
</li>
<li>
<a href="https://slar.se/pages/license.html">License</a>
</li>
<li>
<a href="https://slar.se/pages/projects.html">Projects</a>
</li>
<li><a href="https://slar.se/resume.pdf">Resume</a></li>
<li class="divider"></li>
<li class="">
<a href="https://slar.se/archives.html">Archives</a>
</li>
<li class="divider"></li>
<li><a href="https://slar.se/feeds/all.atom.xml"
type="application/atom+xml" rel="alternate">
<i class="fas fa-rss fa-fw fa-lg"></i> </a></li>
</ul> <!-- /nav -->
</div> <!-- /navbar-collapse -->
</div> <!-- /container -->
</nav> <!-- /navbar -->
<div class="jumbotron" id="overview">
<div class="container">
<h1><a href="https://slar.se/">Programming for fun and profit</a></h1>
<p class="lead">A blog about software engineering, programming languages and technical tinkering</p>
</div>
</div>
<div class="container" id="main-container">
<div class="row">
<div class="col-md-9" id="content">
<article itemscope="itemscope" itemtype="http://schema.org/BlogPosting">
<header class="article-header">
<abbr class="article-header-date">
Sat 03 October 2020
</abbr> <h1 class="article-header-title">
<a href="https://slar.se/essential-pytest-2.html" rel="bookmark"
title="Permalink to Essential pytest pt. 2: Selecting tests to run">
Essential pytest pt. 2: Selecting tests to run
</a>
</h1><div class="article-header-info">
<p>
Posted by <a href="https://slar.se/author/simon-larsen.html">Simon Larsén</a>
in
<a href="https://slar.se/category/testing.html">
Testing</a>
</p>
</div> <!-- /.article-header-info --><div class="article-tag-list">
<span class="label label-default">Tags</span>
<a href="https://slar.se/tag/python.html"><i class="fas fa-tag"></i>python</a>
<a href="https://slar.se/tag/pytest.html"><i class="fas fa-tag"></i>pytest</a>
<a href="https://slar.se/tag/testing.html"><i class="fas fa-tag"></i>testing</a>
</div> </header>
<div class="content-body" itemprop="text articleBody">
<p>This is the second part of a series of small articles detailing some of the
functionality of the <a href="https://docs.pytest.org/en/latest/">pytest</a> testing
framework that I find most essential. The series assumes you know how to run
tests with <code>pytest</code> already.</p>
<p>In this second part, we'll take a look at the <code>-k</code> and <code>-m</code> options to control
which tests in the test suite are executed.</p>
<h2>The test suite</h2>
<p>In this article, we'll use the test suite from <a href="https://slar.se/essential-pytest-1.html">the first
article</a>.</p>
<div class="highlight"><pre><span></span><code><span class="c1"># test_mul.py</span>
<span class="k">def</span> <span class="nf">mul</span><span class="p">(</span><span class="n">lhs</span><span class="p">,</span> <span class="n">rhs</span><span class="p">):</span>
<span class="k">return</span> <span class="n">lhs</span> <span class="o">*</span> <span class="n">rhs</span>
<span class="k">def</span> <span class="nf">test_multiply_equal_numbers</span><span class="p">():</span>
<span class="k">assert</span> <span class="n">mul</span><span class="p">(</span><span class="mi">5</span><span class="p">,</span> <span class="mi">5</span><span class="p">)</span> <span class="o">==</span> <span class="mi">25</span>
<span class="k">def</span> <span class="nf">test_multiply_by_zero</span><span class="p">():</span>
<span class="k">assert</span> <span class="n">mul</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="mi">0</span><span class="p">)</span> <span class="o">==</span> <span class="mi">0</span>
<span class="k">def</span> <span class="nf">test_multiply_different_numbers</span><span class="p">():</span>
<span class="k">assert</span> <span class="n">mul</span><span class="p">(</span><span class="mi">5</span><span class="p">,</span> <span class="mi">3</span><span class="p">)</span> <span class="o">==</span> <span class="mi">15</span>
</code></pre></div>
<p>Note that <code>mul</code> is now correctly implemented, so all tests will pass.</p>
<div class="highlight"><pre><span></span><code>$<span class="w"> </span>pytest<span class="w"> </span>-v
<span class="o">==========================</span><span class="w"> </span><span class="nb">test</span><span class="w"> </span>session<span class="w"> </span><span class="nv">starts</span><span class="w"> </span><span class="o">===========================</span>
platform<span class="w"> </span>linux<span class="w"> </span>--<span class="w"> </span>Python<span class="w"> </span><span class="m">3</span>.8.5,<span class="w"> </span>pytest-6.1.0,<span class="w"> </span>py-1.9.0,<span class="w"> </span>pluggy-0.13.1
cachedir:<span class="w"> </span>.pytest_cache
rootdir:<span class="w"> </span>/home/slarse/python
collected<span class="w"> </span><span class="m">3</span><span class="w"> </span>items<span class="w"> </span>
mul.py::test_multiply_equal_numbers<span class="w"> </span>PASSED<span class="w"> </span><span class="o">[</span><span class="w"> </span><span class="m">33</span>%<span class="o">]</span>
mul.py::test_multiply_by_zero<span class="w"> </span>PASSED<span class="w"> </span><span class="o">[</span><span class="w"> </span><span class="m">66</span>%<span class="o">]</span>
mul.py::test_multiply_different_numbers<span class="w"> </span>PASSED<span class="w"> </span><span class="o">[</span><span class="m">100</span>%<span class="o">]</span>
<span class="o">===========================</span><span class="w"> </span><span class="m">3</span><span class="w"> </span>passed<span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="m">0</span>.01s<span class="w"> </span><span class="o">============================</span>
</code></pre></div>
<p>Now, let's learn how to run subsets of these tests, without modifying the
source code.</p>
<h2>Using the <code>-k</code> option to select tests by substring matching</h2>
<p>The <code>-k</code> option is wonderful, and allows us to select a subset of tests to
execute based on simple substring matching. The simplest use of <code>-k</code> is to
provide it with a whitespace-less string. Any test with a name that <em>contains</em>
that string will be executed. To be clear, the name of a test is e.g.
<code>mul.py::test_multiply_equal_numbers</code>, that is to say, the qualified path to it.</p>
<p>As a simple example, we can select only the test that multiplies by zero like
so.</p>
<div class="highlight"><pre><span></span><code>$<span class="w"> </span>pytest<span class="w"> </span>-v<span class="w"> </span>-k<span class="w"> </span><span class="nv">zero</span>
<span class="o">==========================</span><span class="w"> </span><span class="nb">test</span><span class="w"> </span>session<span class="w"> </span><span class="nv">starts</span><span class="w"> </span><span class="o">===========================</span>
platform<span class="w"> </span>linux<span class="w"> </span>--<span class="w"> </span>Python<span class="w"> </span><span class="m">3</span>.8.5,<span class="w"> </span>pytest-6.1.0,<span class="w"> </span>py-1.9.0,<span class="w"> </span>pluggy-0.13.1
cachedir:<span class="w"> </span>.pytest_cache
rootdir:<span class="w"> </span>/home/slarse/python
collected<span class="w"> </span><span class="m">3</span><span class="w"> </span>items<span class="w"> </span>/<span class="w"> </span><span class="m">2</span><span class="w"> </span>deselected<span class="w"> </span>/<span class="w"> </span><span class="m">1</span><span class="w"> </span>selected<span class="w"> </span>
test_mul.py::test_multiply_by_zero<span class="w"> </span>PASSED<span class="w"> </span><span class="o">[</span><span class="m">100</span>%<span class="o">]</span>
<span class="o">====================</span><span class="w"> </span><span class="m">1</span><span class="w"> </span>passed,<span class="w"> </span><span class="m">2</span><span class="w"> </span>deselected<span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="m">0</span>.05s<span class="w"> </span><span class="o">=====================</span>
</code></pre></div>
<p>Note that 2 tests were deselected. It is also possible to create logical
expressions using <code>not</code>, <code>or</code> and <code>and</code>. <code>not</code> simply inverts the condition:
any test that does <em>not</em> match the substring is executed.</p>
<div class="highlight"><pre><span></span><code>$<span class="w"> </span>pytest<span class="w"> </span>-v<span class="w"> </span>-k<span class="w"> </span><span class="s1">'not zero'</span>
<span class="o">==========================</span><span class="w"> </span><span class="nb">test</span><span class="w"> </span>session<span class="w"> </span><span class="nv">starts</span><span class="w"> </span><span class="o">===========================</span>
platform<span class="w"> </span>linux<span class="w"> </span>--<span class="w"> </span>Python<span class="w"> </span><span class="m">3</span>.8.5,<span class="w"> </span>pytest-6.1.0,<span class="w"> </span>py-1.9.0,<span class="w"> </span>pluggy-0.13.1
cachedir:<span class="w"> </span>.pytest_cache
rootdir:<span class="w"> </span>/home/slarse/python
collected<span class="w"> </span><span class="m">3</span><span class="w"> </span>items<span class="w"> </span>/<span class="w"> </span><span class="m">1</span><span class="w"> </span>deselected<span class="w"> </span>/<span class="w"> </span><span class="m">2</span><span class="w"> </span>selected<span class="w"> </span>
test_mul.py::test_multiply_equal_numbers<span class="w"> </span>PASSED<span class="w"> </span><span class="o">[</span><span class="w"> </span><span class="m">50</span>%<span class="o">]</span>
test_mul.py::test_multiply_different_numbers<span class="w"> </span>PASSED<span class="w"> </span><span class="o">[</span><span class="m">100</span>%<span class="o">]</span>
<span class="o">====================</span><span class="w"> </span><span class="m">2</span><span class="w"> </span>passed,<span class="w"> </span><span class="m">1</span><span class="w"> </span>deselected<span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="m">0</span>.05s<span class="w"> </span><span class="o">=====================</span>
</code></pre></div>
<p>With <code>or</code>, we can select tests that match any of a number of substrings.</p>
<div class="highlight"><pre><span></span><code>$<span class="w"> </span>pytest<span class="w"> </span>-v<span class="w"> </span>-k<span class="w"> </span><span class="s1">'equal or different'</span>
<span class="o">==========================</span><span class="w"> </span><span class="nb">test</span><span class="w"> </span>session<span class="w"> </span><span class="nv">starts</span><span class="w"> </span><span class="o">===========================</span>
platform<span class="w"> </span>linux<span class="w"> </span>--<span class="w"> </span>Python<span class="w"> </span><span class="m">3</span>.8.5,<span class="w"> </span>pytest-6.1.0,<span class="w"> </span>py-1.9.0,<span class="w"> </span>pluggy-0.13.1
/usr/bin/python
cachedir:<span class="w"> </span>.pytest_cache
rootdir:<span class="w"> </span>/home/slarse/python
collected<span class="w"> </span><span class="m">3</span><span class="w"> </span>items<span class="w"> </span>/<span class="w"> </span><span class="m">1</span><span class="w"> </span>deselected<span class="w"> </span>/<span class="w"> </span><span class="m">2</span><span class="w"> </span>selected<span class="w"> </span>
test_mul.py::test_multiply_equal_numbers<span class="w"> </span>PASSED<span class="w"> </span><span class="o">[</span><span class="w"> </span><span class="m">50</span>%<span class="o">]</span>
test_mul.py::test_multiply_different_numbers<span class="w"> </span>PASSED<span class="w"> </span><span class="o">[</span><span class="m">100</span>%<span class="o">]</span>
<span class="o">====================</span><span class="w"> </span><span class="m">2</span><span class="w"> </span>passed,<span class="w"> </span><span class="m">1</span><span class="w"> </span>deselected<span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="m">0</span>.06s<span class="w"> </span><span class="o">=====================</span>
</code></pre></div>
<p>Finally, <code>and</code> allows us to select tests that match multiple substrings.</p>
<div class="highlight"><pre><span></span><code>$<span class="w"> </span>pytest<span class="w"> </span>-v<span class="w"> </span>-k<span class="w"> </span><span class="s1">'multiply and equal'</span>
<span class="o">==========================</span><span class="w"> </span><span class="nb">test</span><span class="w"> </span>session<span class="w"> </span><span class="nv">starts</span><span class="w"> </span><span class="o">===========================</span>
platform<span class="w"> </span>linux<span class="w"> </span>--<span class="w"> </span>Python<span class="w"> </span><span class="m">3</span>.8.5,<span class="w"> </span>pytest-6.1.0,<span class="w"> </span>py-1.9.0,<span class="w"> </span>pluggy-0.13.1
/usr/bin/python
cachedir:<span class="w"> </span>.pytest_cache
rootdir:<span class="w"> </span>/home/slarse/python
collected<span class="w"> </span><span class="m">3</span><span class="w"> </span>items<span class="w"> </span>/<span class="w"> </span><span class="m">2</span><span class="w"> </span>deselected<span class="w"> </span>/<span class="w"> </span><span class="m">1</span><span class="w"> </span>selected<span class="w"> </span>
test_mul.py::test_multiply_equal_numbers<span class="w"> </span>PASSED<span class="w"> </span><span class="o">[</span><span class="m">100</span>%<span class="o">]</span>
<span class="o">====================</span><span class="w"> </span><span class="m">1</span><span class="w"> </span>passed,<span class="w"> </span><span class="m">2</span><span class="w"> </span>deselected<span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="m">0</span>.05s<span class="w"> </span><span class="o">=====================</span>
</code></pre></div>
<p>And that's pretty much all there is to the <code>-k</code> option. It's extremely useful
when test suites grow in size, and I use it daily.</p>
<h2>Using the <code>-m</code> option to select by marker</h2>
<p>With <code>-m</code>, we can select tests by <em>markers</em>. You can mark a test function (or
class) by placing a decorator above it.</p>
<div class="highlight"><pre><span></span><code><span class="c1"># test_mul.py</span>
<span class="kn">import</span> <span class="nn">pytest</span>
<span class="k">def</span> <span class="nf">mul</span><span class="p">(</span><span class="n">lhs</span><span class="p">,</span> <span class="n">rhs</span><span class="p">):</span>
<span class="k">return</span> <span class="n">lhs</span> <span class="o">*</span> <span class="n">rhs</span>
<span class="nd">@pytest</span><span class="o">.</span><span class="n">mark</span><span class="o">.</span><span class="n">normcase</span>
<span class="k">def</span> <span class="nf">test_multiply_equal_numbers</span><span class="p">():</span>
<span class="k">assert</span> <span class="n">mul</span><span class="p">(</span><span class="mi">5</span><span class="p">,</span> <span class="mi">5</span><span class="p">)</span> <span class="o">==</span> <span class="mi">25</span>
<span class="nd">@pytest</span><span class="o">.</span><span class="n">mark</span><span class="o">.</span><span class="n">edgecase</span>
<span class="k">def</span> <span class="nf">test_multiply_by_zero</span><span class="p">():</span>
<span class="k">assert</span> <span class="n">mul</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="mi">0</span><span class="p">)</span> <span class="o">==</span> <span class="mi">0</span>
<span class="nd">@pytest</span><span class="o">.</span><span class="n">mark</span><span class="o">.</span><span class="n">normcase</span>
<span class="k">def</span> <span class="nf">test_multiply_different_numbers</span><span class="p">():</span>
<span class="k">assert</span> <span class="n">mul</span><span class="p">(</span><span class="mi">5</span><span class="p">,</span> <span class="mi">3</span><span class="p">)</span> <span class="o">==</span> <span class="mi">15</span>
</code></pre></div>
<p>Note that we must actually import the <code>pytest</code> module to be able to mark tests
with <code>@pytest.mark.x</code>. Now, we can run all tests marked with e.g. <code>normcase</code>
like so.</p>
<div class="highlight"><pre><span></span><code>$<span class="w"> </span>pytest<span class="w"> </span>-v<span class="w"> </span>-m<span class="w"> </span><span class="nv">normcase</span>
<span class="o">==========================</span><span class="w"> </span><span class="nb">test</span><span class="w"> </span>session<span class="w"> </span><span class="nv">starts</span><span class="w"> </span><span class="o">===========================</span>
platform<span class="w"> </span>linux<span class="w"> </span>--<span class="w"> </span>Python<span class="w"> </span><span class="m">3</span>.8.5,<span class="w"> </span>pytest-6.1.0,<span class="w"> </span>py-1.9.0,<span class="w"> </span>pluggy-0.13.1
cachedir:<span class="w"> </span>.pytest_cache
rootdir:<span class="w"> </span>/home/slarse/python
collected<span class="w"> </span><span class="m">3</span><span class="w"> </span>items<span class="w"> </span>/<span class="w"> </span><span class="m">1</span><span class="w"> </span>deselected<span class="w"> </span>/<span class="w"> </span><span class="m">2</span><span class="w"> </span>selected<span class="w"> </span>
test_mul.py::test_multiply_equal_numbers<span class="w"> </span>PASSED<span class="w"> </span><span class="o">[</span><span class="w"> </span><span class="m">50</span>%<span class="o">]</span>
test_mul.py::test_multiply_different_numbers<span class="w"> </span>PASSED<span class="w"> </span><span class="o">[</span><span class="m">100</span>%<span class="o">]</span>
<span class="o">============================</span><span class="w"> </span>warnings<span class="w"> </span><span class="nv">summary</span><span class="w"> </span><span class="o">============================</span>
test_mul.py:6
<span class="w"> </span>/home/slarse/python/test_mul.py:6:<span class="w"> </span>PytestUnknownMarkWarning:<span class="w"> </span>Unknown<span class="w"> </span>pytest.mark.normcase<span class="w"> </span>-<span class="w"> </span>is<span class="w"> </span>this<span class="w"> </span>a<span class="w"> </span>typo?<span class="w"> </span>You<span class="w"> </span>can<span class="w"> </span>register<span class="w"> </span>custom<span class="w"> </span>marks<span class="w"> </span>to<span class="w"> </span>avoid<span class="w"> </span>this<span class="w"> </span>warning<span class="w"> </span>-<span class="w"> </span><span class="k">for</span><span class="w"> </span>details,<span class="w"> </span>see<span class="w"> </span>https://docs.pytest.org/en/stable/mark.html
<span class="w"> </span>@pytest.mark.normcase
<span class="o">[</span>...<span class="w"> </span><span class="m">2</span><span class="w"> </span>WARNINGS<span class="w"> </span>OMITTED<span class="w"> </span>...<span class="o">]</span>
--<span class="w"> </span>Docs:<span class="w"> </span>https://docs.pytest.org/en/stable/warnings.html
<span class="o">==============</span><span class="w"> </span><span class="m">2</span><span class="w"> </span>passed,<span class="w"> </span><span class="m">1</span><span class="w"> </span>deselected,<span class="w"> </span><span class="m">3</span><span class="w"> </span>warnings<span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="m">0</span>.01s<span class="w"> </span><span class="o">===============</span>
</code></pre></div>
<p>Note that this resulted in 3 warnings, one for each of the markings. The reason
for this is that newer versions of <code>pytest</code> want you to <em>register</em> markers, <a href="https://docs.pytest.org/en/stable/example/markers.html#registering-markers">as
described
here</a>.
The purpose of this is to avoid users misspelling markers, and registering them
will make the warnings go away.</p>
<p>As might be expected, the <code>-m</code> option also accepts logical expressions using
<code>not</code>, <code>and</code> and <code>or</code>, just like the <code>-k</code> option does. Personally, I very rarely
use <code>-m</code> when using <code>pytest</code>, but some people swear by it, which is why I wanted
to include it in this article.</p>
<h2>Trick: Grouping related tests into classes makes selection easier</h2>
<p>A trick that I like to employ is to group related tests into classes. The class
name is then incorporated into the test's name, and it becomes very easy to
select tests that are part of the same class. Here's a simple example, where I'm
testing two functions in the same module <code>test_arithmetics.py</code>:</p>
<div class="highlight"><pre><span></span><code><span class="c1"># test_arithmetics.py</span>
<span class="k">def</span> <span class="nf">mul</span><span class="p">(</span><span class="n">lhs</span><span class="p">,</span> <span class="n">rhs</span><span class="p">):</span>
<span class="k">return</span> <span class="n">lhs</span> <span class="o">*</span> <span class="n">rhs</span>
<span class="k">def</span> <span class="nf">div</span><span class="p">(</span><span class="n">lhs</span><span class="p">,</span> <span class="n">rhs</span><span class="p">):</span>
<span class="k">return</span> <span class="n">lhs</span> <span class="o">/</span> <span class="n">rhs</span>
<span class="k">class</span> <span class="nc">TestMul</span><span class="p">:</span>
<span class="w"> </span><span class="sd">"""Tests for the mul function."""</span>
<span class="k">def</span> <span class="nf">test_multiply_equal_numbers</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">assert</span> <span class="n">mul</span><span class="p">(</span><span class="mi">5</span><span class="p">,</span> <span class="mi">5</span><span class="p">)</span> <span class="o">==</span> <span class="mi">25</span>
<span class="k">def</span> <span class="nf">test_multiply_by_zero</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">assert</span> <span class="n">mul</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="mi">0</span><span class="p">)</span> <span class="o">==</span> <span class="mi">0</span>
<span class="k">def</span> <span class="nf">test_multiply_different_numbers</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">assert</span> <span class="n">mul</span><span class="p">(</span><span class="mi">5</span><span class="p">,</span> <span class="mi">3</span><span class="p">)</span> <span class="o">==</span> <span class="mi">15</span>
<span class="k">class</span> <span class="nc">TestDiv</span><span class="p">:</span>
<span class="w"> </span><span class="sd">"""Tests for the div function."""</span>
<span class="k">def</span> <span class="nf">test_divide_equal_numbers</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">assert</span> <span class="n">div</span><span class="p">(</span><span class="mi">10</span><span class="p">,</span> <span class="mi">10</span><span class="p">)</span> <span class="o">==</span> <span class="mi">1</span>
</code></pre></div>
<p>Note that in grouping test functions into test classes, the <code>self</code> argument
must be added. This is a little bit annoying, as I rarely if ever use the
<code>self</code> argument in a test case, but it's something that has to be done.</p>
<p>Now, I can for example run only the tests in <code>TestDiv</code> like so.</p>
<div class="highlight"><pre><span></span><code>$<span class="w"> </span>pytest<span class="w"> </span>-v<span class="w"> </span>-k<span class="w"> </span><span class="nv">TestDiv</span>
<span class="o">==========================</span><span class="w"> </span><span class="nb">test</span><span class="w"> </span>session<span class="w"> </span><span class="nv">starts</span><span class="w"> </span><span class="o">===========================</span>
platform<span class="w"> </span>linux<span class="w"> </span>--<span class="w"> </span>Python<span class="w"> </span><span class="m">3</span>.8.5,<span class="w"> </span>pytest-6.1.0,<span class="w"> </span>py-1.9.0,<span class="w"> </span>pluggy-0.13.1
cachedir:<span class="w"> </span>.pytest_cache
rootdir:<span class="w"> </span>/home/slarse/python
collected<span class="w"> </span><span class="m">4</span><span class="w"> </span>items<span class="w"> </span>/<span class="w"> </span><span class="m">3</span><span class="w"> </span>deselected<span class="w"> </span>/<span class="w"> </span><span class="m">1</span><span class="w"> </span>selected<span class="w"> </span>
test_arithmetics.py::TestDiv::test_divide_equal_numbers<span class="w"> </span>PASSED<span class="w"> </span><span class="o">[</span><span class="m">100</span>%<span class="o">]</span>
<span class="o">====================</span><span class="w"> </span><span class="m">1</span><span class="w"> </span>passed,<span class="w"> </span><span class="m">3</span><span class="w"> </span>deselected<span class="w"> </span><span class="k">in</span><span class="w"> </span><span class="m">0</span>.05s<span class="w"> </span><span class="o">=====================</span>
</code></pre></div>
<p>Note that the test name that's printed above includes the class name, which is
why it is possible to select it with <code>-k</code>. Of course, grouping related tests
into modules is equally viable, as the module name (here, <code>test_arithmetics.py</code>)
is also part of the test name. I typically do both by creating one test module
per module of production code, and one test class per production code function.
This allows me to easily select tests at two levels of granularity, which comes
in very handy.</p>
<h2>Summary</h2>
<p>Selecting a subset of test cases to run is crucial to my development workflow.
When there are 100s or even 1000s of tests to run, running all of them is often
not what you want to do. My preferred way of selecting test cases is by using
the <code>-k</code> option to match substrings of test names, but the <code>-m</code> option is also
there for those that like to put marker decorators in their code. Finally,
grouping related tests into modules and classes allows for easy selection of
tests on two levels of granularity, which is something that I exploit daily.</p>
</div>
</article>
</div><!-- /content -->
<div class="col-md-3 sidebar-nav" id="sidebar">
<div class="row">
<div class="col-xs-6 col-md-12">
<h4><i class="fas fa-comment fa-fw fa-lg"></i> Social</h4>
<ul class="list-unstyled social-links">
<li><a href="https://www.linkedin.com/in/simon-lars%C3%A9n-b665b3102/" target="_blank">
<i class="fab fa-linkedin fa-fw fa-lg" title="LinkedIn"></i>
LinkedIn
</a></li>
<li><a href="https://github.com/slarse" target="_blank">
<i class="fab fa-github-square fa-fw fa-lg" title="GitHub"></i>
GitHub
</a></li>
</ul>
</div>
<div class="col-xs-6 col-md-12">
<h4><i class="fas fa-folder fa-fw fa-lg"></i> Categories</h4>
<ul class="list-unstyled category-links">
<li><a href="https://slar.se/category/blog.html" >
<i class="fas fa-folder-open fa-fw fa-lg"></i> Blog</a></li>
<li><a href="https://slar.se/category/linux.html" >
<i class="fas fa-folder-open fa-fw fa-lg"></i> Linux</a></li>
<li><a href="https://slar.se/category/programming.html" >
<i class="fas fa-folder-open fa-fw fa-lg"></i> Programming</a></li>
<li><a href="https://slar.se/category/reviews.html" >
<i class="fas fa-folder-open fa-fw fa-lg"></i> Reviews</a></li>
<li><a href="https://slar.se/category/testing.html" >
<i class="fas fa-folder-open fa-fw fa-lg"></i> Testing</a></li>
<li><a href="https://slar.se/category/tip-of-the-week.html" >
<i class="fas fa-folder-open fa-fw fa-lg"></i> Tip of the Week</a></li>
</ul>
</div>
</div> <!-- /row -->
<h4><i class="fas fa-tags fa-fw fa-lg"></i> Tags</h4>
<p class="tag-cloud">
<span class="tag-1">
<a href="https://slar.se/tag/python.html">
<i class="fas fa-tag"></i>
python
</a>
</span>
<span class="tag-2">
<a href="https://slar.se/tag/book-review.html">
<i class="fas fa-tag"></i>
book review
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/tree-sitter.html">
<i class="fas fa-tag"></i>
tree-sitter
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/html.html">
<i class="fas fa-tag"></i>
html
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/cybersecurity.html">
<i class="fas fa-tag"></i>
cybersecurity
</a>
</span>
<span class="tag-3">
<a href="https://slar.se/tag/database.html">
<i class="fas fa-tag"></i>
database
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/intellij.html">
<i class="fas fa-tag"></i>
intellij
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/programming-languages.html">
<i class="fas fa-tag"></i>
programming languages
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/man.html">
<i class="fas fa-tag"></i>
man
</a>
</span>
<span class="tag-1">
<a href="https://slar.se/tag/totw.html">
<i class="fas fa-tag"></i>
totw
</a>
</span>
<span class="tag-3">
<a href="https://slar.se/tag/rust.html">
<i class="fas fa-tag"></i>
rust
</a>
</span>
<span class="tag-2">
<a href="https://slar.se/tag/kotlin.html">
<i class="fas fa-tag"></i>
kotlin
</a>
</span>
<span class="tag-3">
<a href="https://slar.se/tag/learning.html">
<i class="fas fa-tag"></i>
learning
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/libinput.html">
<i class="fas fa-tag"></i>
libinput
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/podcast.html">
<i class="fas fa-tag"></i>
podcast
</a>
</span>
<span class="tag-2">
<a href="https://slar.se/tag/linux.html">
<i class="fas fa-tag"></i>
linux
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/enums.html">
<i class="fas fa-tag"></i>
enums
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/null.html">
<i class="fas fa-tag"></i>
null
</a>
</span>
<span class="tag-1">
<a href="https://slar.se/tag/blog.html">
<i class="fas fa-tag"></i>
blog
</a>
</span>
<span class="tag-3">
<a href="https://slar.se/tag/bst.html">
<i class="fas fa-tag"></i>
bst
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/gradle.html">
<i class="fas fa-tag"></i>
gradle
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/parsing.html">
<i class="fas fa-tag"></i>
parsing
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/dependencies.html">
<i class="fas fa-tag"></i>
dependencies
</a>
</span>
<span class="tag-1">
<a href="https://slar.se/tag/bash.html">
<i class="fas fa-tag"></i>
bash
</a>
</span>
<span class="tag-3">
<a href="https://slar.se/tag/postgresql.html">
<i class="fas fa-tag"></i>
postgresql
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/sql.html">
<i class="fas fa-tag"></i>
sql
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/xorg.html">
<i class="fas fa-tag"></i>
xorg
</a>
</span>
<span class="tag-3">
<a href="https://slar.se/tag/git.html">
<i class="fas fa-tag"></i>
git
</a>
</span>
<span class="tag-3">
<a href="https://slar.se/tag/pytest.html">
<i class="fas fa-tag"></i>
pytest
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/indexing.html">
<i class="fas fa-tag"></i>
indexing
</a>
</span>
<span class="tag-3">
<a href="https://slar.se/tag/kuizzy.html">
<i class="fas fa-tag"></i>
kuizzy
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/unit-testing.html">
<i class="fas fa-tag"></i>
unit testing
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/testing-tips.html">
<i class="fas fa-tag"></i>
testing tips
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/css.html">
<i class="fas fa-tag"></i>
css
</a>
</span>
<span class="tag-3">
<a href="https://slar.se/tag/java.html">
<i class="fas fa-tag"></i>
java
</a>
</span>
<span class="tag-3">
<a href="https://slar.se/tag/tornadofx.html">
<i class="fas fa-tag"></i>
tornadofx
</a>
</span>
<span class="tag-3">
<a href="https://slar.se/tag/wayland.html">
<i class="fas fa-tag"></i>
wayland
</a>
</span>
<span class="tag-3">
<a href="https://slar.se/tag/data-structures.html">
<i class="fas fa-tag"></i>
data structures
</a>
</span>
<span class="tag-1">
<a href="https://slar.se/tag/software-engineering.html">
<i class="fas fa-tag"></i>
software engineering
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/nil.html">
<i class="fas fa-tag"></i>
nil
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/syntax.html">
<i class="fas fa-tag"></i>
syntax
</a>
</span>
<span class="tag-3">
<a href="https://slar.se/tag/testing.html">
<i class="fas fa-tag"></i>
testing
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/repobee.html">
<i class="fas fa-tag"></i>
repobee
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/xps15.html">
<i class="fas fa-tag"></i>
xps15
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/github.html">
<i class="fas fa-tag"></i>
github
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/psql.html">
<i class="fas fa-tag"></i>
psql
</a>
</span>
<span class="tag-3">
<a href="https://slar.se/tag/go.html">
<i class="fas fa-tag"></i>
go
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/dependabot.html">
<i class="fas fa-tag"></i>
dependabot
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/javascript.html">
<i class="fas fa-tag"></i>
javascript
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/sway.html">
<i class="fas fa-tag"></i>
sway
</a>
</span>
<span class="tag-3">
<a href="https://slar.se/tag/exposed.html">
<i class="fas fa-tag"></i>
exposed
</a>
</span>
<span class="tag-4">
<a href="https://slar.se/tag/x11.html">
<i class="fas fa-tag"></i>
x11
</a>
</span>
<span class="tag-3">
<a href="https://slar.se/tag/neovim.html">
<i class="fas fa-tag"></i>
neovim
</a>
</span>
</p>
<h4><i class="fas fa-rss fa-fw fa-lg"></i> Feeds</h4>
<ul class="list-unstyled">
<li><a href="https://slar.se/feeds/all.atom.xml"
type="application/atom+xml" rel="alternate">
<i class="fas fa-rss-square fa-fw fa-lg"></i> Atom Feed</a></li>
</ul>
<hr />
</div><!--/sidebar -->
</div><!--/row-->
</div><!--/.container /#main-container -->
<footer id="site-footer">
<small>
<p xmlns:cc="http://creativecommons.org/ns#" xmlns:dct="http://purl.org/dc/terms/"><span property="dct:title">Code snippets</span> licensed under <a href="http://creativecommons.org/publicdomain/zero/1.0?ref=chooser-v1" target="_blank" rel="license noopener noreferrer" style="display:inline-block;">CC0 1.0<img style="height:22px!important;margin-left:3px;vertical-align:text-bottom;" src="https://mirrors.creativecommons.org/presskit/icons/cc.svg?ref=chooser-v1"><img style="height:22px!important;margin-left:3px;vertical-align:text-bottom;" src="https://mirrors.creativecommons.org/presskit/icons/zero.svg?ref=chooser-v1"></a></p>
<p xmlns:cc="http://creativecommons.org/ns#" xmlns:dct="http://purl.org/dc/terms/">Texts (natural language) licensed under <a href="http://creativecommons.org/licenses/by/4.0/?ref=chooser-v1" target="_blank" rel="license noopener noreferrer" style="display:inline-block;">CC BY 4.0<img style="height:22px!important;margin-left:3px;vertical-align:text-bottom;" src="https://mirrors.creativecommons.org/presskit/icons/cc.svg?ref=chooser-v1"><img style="height:22px!important;margin-left:3px;vertical-align:text-bottom;" src="https://mirrors.creativecommons.org/presskit/icons/by.svg?ref=chooser-v1"></a></p>
</small>
<address id="site-colophon">
<p class="text-center text-muted">
Site built using <a href="http://getpelican.com/" target="_blank">Pelican</a>
• Theme based on
<a href="http://www.voidynullness.net/page/voidy-bootstrap-pelican-theme/"
target="_blank">VoidyBootstrap</a> by
<a href="http://voidynullness.net"
target="_blank">RKI</a>
</p>
</address><!-- /colophon -->
</footer>
<!-- javascript -->
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js" integrity="sha384-nvAa0+6Qg9clwYCGGPpDQLVpLNn0fRaROjHqs13t4Ggj3Ez50XnGQqc/r8MhnRDZ" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"
integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa"
crossorigin="anonymous"></script>
<script src="https://files.stork-search.net/releases/v1.2.1/stork.js"></script>
<script>
stork.register("sitesearch", "https://slar.se/search-index.st")
</script> </body>
</html>