forked from hakimel/reveal.js
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy patharrange_act_assert.html
executable file
·1207 lines (1072 loc) · 53.3 KB
/
arrange_act_assert.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
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Testimony</title>
<meta name="description" content="Keynote on testing">
<meta name="author" content="Milan Popovic">
<meta name="apple-mobile-web-app-capable" content="yes" />
<meta name="apple-mobile-web-app-status-bar-style" content="black-translucent" />
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no, minimal-ui">
<link rel="stylesheet" href="css/reveal.css">
<link rel="stylesheet" href="css/theme/black.css" id="theme">
<link rel="stylesheet" href="css/presentation/arrange_act_assert.css">
<!-- Code syntax highlighting -->
<link rel="stylesheet" href="lib/css/zenburn.css">
<!-- Printing and PDF exports -->
<script>
var link = document.createElement( 'link' );
link.rel = 'stylesheet';
link.type = 'text/css';
link.href = window.location.search.match( /print-pdf/gi ) ? 'css/print/pdf.css' : 'css/print/paper.css';
document.getElementsByTagName( 'head' )[0].appendChild( link );
</script>
<!--[if lt IE 9]>
<script src="lib/js/html5shiv.js"></script>
<![endif]-->
</head>
<body>
<div class="reveal">
<!-- Any section element inside of this container is displayed as a slide -->
<div class="slides">
<section>
<p class="left_align">
What is main property of bad code?
</p>
<h2 class="fragment">
<span class="red_text">
It's untestable
</span>
</h2>
</section>
<section>
<h2>Kent Beck's rules of simple code</h2>
<ul>
<ol>
1. Runs all the tests
</ol>
<ol>
2. Contains no duplication
</ol>
<ol>
3. Express the intent of programmer
</ol>
<ol>
4. Minimizes the number of classes and methods
</ol>
</ul>
<p class="fragment red_text">
Given in order of importance
</p>
<aside class="notes">
Kent also said in his book TDD by example:
"No software engineers release even the tiniest change without testing, except the very
confident and the very sloppy"
</aside>
</section>
<section>
<p class="left_align">
“
<q>
The degree to which you know how your software behaves is the degree to which you have
accurately tested it.
</q>
” - Max Kanat-Alexander
</p>
</section>
<section>
<h1>Arrange Act Assert</h1>
<p>
<small>Presented by <a href="http://milanpopovic.me">Milan Popović</a> / <a href="http://twitter.com/komita1981">@komita1981</a></small>
</p>
</section>
<section>
<h2>Me</h2>
<p class="left_align">
PHP developer
</p>
<p class="left_align">
Work for Navus Consulting
</p>
<p class="left_align">
I like to learn and share knowledge
</p>
<p class="left_align">
Active member of PHP Srbija
</p>
</section>
<section>
<h2>What is testing?</h2>
<p class="fragment">
Testing is the activity of finding out whether a piece of code produces the intended behavior
</p>
</section>
<section>
<section>
<h2>What do people think about testing?</h2>
</section>
<section>
<img class="noframes" src="img/arrange_act_assert/i-dont-always-test-my-code.jpg">
</section>
<section>
<p>
<img class="noframes" src="img/arrange_act_assert/code_without_tests.jpeg">
</p>
<aside class="notes">
Time consuming - Who has time to write tests???
</aside>
</section>
<section>
<p>
<img class="noframes" src="img/arrange_act_assert/hard-work.jpg" height="600px" width="790px">
</p>
<aside class="notes">
Testing is hard
</aside>
</section>
<section>
<p>
<img class="noframes" src="img/arrange_act_assert/steep_learning_curve.jpg">
</p>
<aside class="notes">
Steep learning curve
</aside>
</section>
<section>
<p>
<img class="noframes" src="img/arrange_act_assert/no-money.jpg">
</p>
<aside class="notes">
Don’t make anybody any money
</aside>
</section>
<section>
<p class="left_align">
Time consuming
</p>
<p class="left_align">
Testing is hard
</p>
<p class="left_align">
Steep learning curve
</p>
<p class="left_align">
Don’t make anybody any money
</p>
</section>
</section>
<section>
<h2>What testing really is?</h2>
<p class="fragment left_align">
Prove you've done your work
</p>
<p class="fragment left_align">
Reduce number of bugs
</p>
<p class="fragment left_align">
Facilitate change
</p>
<p class="fragment left_align">
Help you make better code design - easier to maintain
</p>
<p class="fragment left_align">
Ensures stable, long lasting application
</p>
<p class="fragment left_align">
Improve understanding how clients are going to use your code
</p>
<p class="fragment left_align">
Enhance security
</p>
<p class="fragment left_align">
Provide free documentation
</p>
<aside class="notes">
Prove you've done your work - Help you check much faster if you're work is done. Testing is an
insurance that the system works.<br/><br/>
Facilitates change - protect you from breaking things - guard from regression bugs. Let you apply
changes with less worries - refactoring will improve things without breaking anything.<br/><br/>
Reduce number of bugs - Having a bug in the code means carrying a
risk. Utilising a set of unit tests, engineers can dramatically reduce number of bugs and the
risk with untested code - It better for you that you find your bugs than your client.
</aside>
</section>
<section>
<h2>Automated testing</h2>
<p class="red_text left_align">
When I say testing I mean AUTOMATED testing
</p>
<p class="left_align">
Automated testing is fun and a key point for software quality
</p>
</section>
<section>
<h2>Manual Testing</h2>
<p class="left_align">
Time consuming
</p>
<p class="left_align">
Slow
</p>
<p class="left_align">
Expensive
</p>
<p class="left_align">
Unreliable
</p>
<p class="left_align">
Boring
</p>
</section>
<section>
<blockquote style="width:100%; font-size: 1.4em;">
Take away my <span class="fragment fade-out">people</span>,
but leave my <span class="fragment fade-out">factories</span>,
and soon <span class="fragment fade-out">grass will grow on the factory floors</span>.<br />
Take away my <span class="fragment fade-out">factories</span>, but leave my <span class="fragment fade-out">people</span>, and soon we will have a new and better <span class="fragment fade-out">factory</span>.
<div style="text-align: right;">- Andrew Carnegie</div>
</blockquote>
</section>
<section style="font-size: 1.7em;">
Take away my <span class="fragment fade-in">test suites</span>,
but leave my <span class="fragment fade-in">source code</span>,
and soon <span class="fragment fade-in">the codebase will be expensive and bitrotten</span>.<br />
Take away my <span class="fragment fade-in">source code</span>,
but leave my <span class="fragment fade-in">test suites</span>,
and soon we will have a new and better <span class="fragment fade-in">codebase</span>.
</section>
<section>
<section>
<h2>Test types</h2>
<p class="fragment">
Acceptance (end-to-end)<br/>
Test as if end user would use the whole system/feature
</p>
<p class="fragment">
Integration<br/>
Test how different parts of system work together
</p>
<p class="fragment">
Unit<br/>
Test single unit of code - mock all dependencies
</p>
<aside class="notes">
Acceptance tests will help you to sell your code, unit tests will help you to maintain your
code.
Good ideas often fail in practice, and in the world of testing, one pervasive good idea that
often fails in practice is a testing strategy built around end-to-end tests.
Unit tests do have one major disadvantage: even if the units work well in isolation, you do
not know if they work well together. But even then, you do not necessarily need end-to-end
tests. For that, you can use an integration test. An integration test takes a small group
of units, often two units, and tests their behavior as a whole, verifying that they
coherently work together. If two units do not integrate properly, why write an end-to-end
test when you can write a much smaller, more focused integration test that will detect the
same bug? While you do need to think larger, you only need to think a little larger to
verify that units work together.
</aside>
</section>
<section>
<img class="noframes" src="img/arrange_act_assert/testing_pyramid.png">
<p class="left_align">
The higher we go - fewer number of tests, slower feedback, higher cost
</p>
<aside class="notes">
Width = Number of tests
The bulk of your tests are unit tests at the bottom of the pyramid. As you move up the
pyramid, your tests gets larger, but at the same time the number of tests (the width of your
pyramid) gets smaller.
</aside>
</section>
<section>
<h2>Google team suggest</h2>
<ul>
<li>
E2E - 10 %
</li>
<li>
Integration - 20%
</li>
<li>
Unit - 70%
</li>
</ul>
<aside class="notes">
As a good first guess, Google often suggests a 70/20/10 split:
70% unit tests, 20% integration tests, and 10% end-to-end tests. The exact mix will be
different for each team, but in general, it should retain that pyramid shape
</aside>
</section>
</section>
<section>
<section>
<h2>
What is unit testing?
</h2>
</section>
<section>
<p class="left_align">
“
<q>
A unit test is a piece of a code (usually a method) that invokes another piece of code and
checks the correctness of some assumptions after- ward. If the assumptions turn out to be wrong,
the unit test has failed. A unit is a method or function. </q>
” - Roy Osherove
</p>
</section>
<section>
<p class="left_align">
A software testing method to test individual unit of source code - a method in class or a piece of code
</p>
<p class="fragment left_align">
The purpose of unit testing is not for finding bugs
</p>
<p class="fragment left_align">
Specification for the expected behaviours of the code under test
</p>
<aside class="notes">
When writing unit tests we are focusing on describing one unit of behaviour at a time, and how
objects communicate in order to achieve that behaviour.
Each unit test sends a specific input to a method and verifies that the method returns the
expected value, or takes the expected action. Unit tests prove that the code you are testing
does in fact do what you expect it to do.
The purpose of unit testing is not for finding bugs. It’s a specification for the expected
behaviours of the code under test. The code under test is the implementation for those expected
behaviours. So unit test and the code under test are used to check the correctness of each other,
and protect each other. Later when someone changed the code under test, and it changed the
behaviour that is expected by the original author, the test will fail. If you code is covered by
reasonable unit test, you can maintain the code without breaking the existing feature.
That’s why Michael Feathers define legacy code as code without unit test.
</aside>
</section>
<section>
<h2>3 A of Unit testing</h2>
<p class="left_align">
<span class="red_text">A</span>rrange objects, creating and setting them up as necessary.
</p>
<p class="left_align">
<span class="red_text">A</span>ct on an object
</p>
<p class="left_align">
<span class="red_text">A</span>ssert that something is as expected
</p>
</section>
<section>
<p class="left_align">
Arrange = Setup
</p>
<p class="left_align">
Act = Poke
</p>
<p class="left_align">
Assert = Verify
</p>
<aside class="notes">
Meszaros adds one more element - teardown (cleanup)
Bill Wake coined this as 3 A - TDD by example book
</aside>
</section>
<section>
<pre><code data-trim contenteditable>
public function testSuccessful()
{
// ARRANGE
$d = $this->prophesize('\SomeNamespace\SomePackage\SomeDriverInterface');
$driver->doSomething()->shouldBeCalled()->willReturn('value');
$testedClass = new TestedClass($driver);
// ACT
$testResult = $testedClass->testedMethod();
// ASSERT
$this->assertSomething($expectedResult, $testResult);
}
</code></pre>
</section>
<section>
<h2>
Write unit tests before or after code?
</h2>
<p class="fragment left_align">
After - You test what you code - Test Last <br/>
Development Driven Testing - <span class="red_text">DDT</span>
</p>
<p class="fragment left_align">
Before - You code what you test - Test First<br/>
Test Driven Development - <span class="red_text">TDD</span>
</p>
</section>
<section>
<img class="noframes" src="img/arrange_act_assert/ddt_circle_of_life.png">
<aside class="notes">
Test Last = Test-After Development (TAD)
TAD programmers want to verify their code, too, but they typically have little interest in
treating the tests as “specifications by example.” For them, the usually singular goal of unit
testing is to verify whether or not some aspects of the code work. These unit tests typically
cover up to two-thirds of the code base. Other forms of integration tests can increase effective
coverage, but unit tests are the closest reliable documentation for the code you’re modifying.
The real sticking point with TAD is productivity. When you don’t think about how to craft code
so it’s testable, you’ll often end up with code that is near-impossible to test. The test-writer
has to either rework it or use a lot of finesse to avoid rework. This makes testing feel like a
waste of time. No wonder so few programmers have fully embraced unit-testing! We find TAD to be
simply less fun, less beneficial, less productive, and more frustrating than TDD.
</aside>
</section>
<section>
<h2>
The Three Laws of TDD
</h2>
<ol>
<li>
You may not write production code until you have written a failing unit test
</li>
<li>
You may not write more of a unit test than is sufficient to fail
</li>
<li>
You may not write more production code than is sufficient to pass the currently failing
test
</li>
</ol>
</section>
<section>
<img class="noframes" src="img/arrange_act_assert/tdd_circle_of_life.png">
<aside class="notes">
With TDD, every line of code has a reason to exist, with tests to back it up.
Only write code if you absolutely have to and always know what your code is supposed to do before
you start writing it - and that is what TDD approach provides for you
“Red-Green-Refactor,” meaning that you start with a failing test, then pass it, and then make
your code readable and more maintainable.
</aside>
</section>
<section>
<p>
<img class="noframes" src="img/arrange_act_assert/test_statistics.png">
</p>
<p>
IBM & Microsoft - TDD - 20-40% longer to complete but 40-90% fewer bugs in production
</p>
</section>
<section>
<blockquote>
By 2022 it will be not be possible to get a professional programming job if you do not practice
TDD routinely - Allan Kelly
</blockquote>
</section>
</section>
<section>
<section>
<h2>Testing doubles</h2>
<ul>
<li class="left_align">Dummy</li>
<li class="left_align">Fake</li>
<li class="left_align">Stub</li>
<li class="left_align">Mock</li>
<li class="left_align">Spy</li>
</ul>
<aside class="notes">
Test doubles are a way of replacing all classes in our tests other than the one we are
testing. They give us control on direct and indirect outputs that would have been generated
by those classes. Understanding the role of the test double helps us to write better tests,
and thus better code. If we manage to isolate the “collaborators” (the other objects
involved in our test) using doubles and test our objects in isolation, then we have achieved
modularity: our code is decoupled and the communication between objects is documented by our
tests.
I prefer expectations when test-driving new behavior, because they keep my design honest;
but spies when rescuing legacy code, because I already know that the design is terrible.
J. B. Rainsberger
</aside>
</section>
<section>
<h2>Dummy</h2>
<p class="left_align">
Objects are passed around but never actually used
</p>
<p class="left_align">
Passed around for typehinting
</p>
<p class="left_align">
No behaviour
</p>
</section>
<section>
<pre><code data-trim contenteditable>
class CustomerCardPrinter
{
private $printer;
private $customer;
public function __construct(PrinterInterface $printer, CustomerInterface $customer)
{
$this->printer = $printer;
$this->customer = $customer;
}
public function print()
{
if (! $this->printer->isAvailable()){
return false;
}
$customerName = $customer->getName();
// some code goes here
}
}
class CustomerCardPrinterTest
{
public function testPrinterNotAvailable()
{
$printer = $this->prophesize('\SomeNamespace\SomePackage\PrinterInterface');
$printer->isAvailable()->willReturn(false);
$customer = $this->prophesize('\SomeNamespace\SomeOtherPackage\CustomerInterface');
$customerCardPrinter = new CustomerCardPrinter($printer->reveal(), $customer->reveal());
$printResult = $customerCardPrinter->print();
$this->assertFalse($testResult);
}
}
</code></pre>
</section>
<section>
<h2>Fake</h2>
<p class="left_align">
The output of the method isn’t important
</p>
<pre><code data-trim contenteditable>
interface PrinterInterface
{
public function isAvailable();
}
class Printer implements PrinterInterface
{
public function isAvailable()
{
// some code goes here
}
}
class FakePrinter implements PrinterInterface
{
public function isAvailable()
{
return true;
}
}
</code></pre>
</section>
<section>
<h2>Stub</h2>
<p class="left_align">
Has (basic) behaviour but no expectations
</p>
<p class="left_align">
It does not matter how many times a method is called - Doesn't have to be called
</p>
<p class="left_align">
Promises it will always return the same thing (willReturn())
</p>
</section>
<section>
<pre><code data-trim contenteditable>
class CustomerCardPrinter
{
private $printer;
private $customer;
public function __construct(PrinterInterface $printer, CustomerInterface $customer)
{
$this->printer = $printer;
$this->customer = $customer;
}
public function print()
{
if (! $this->printer->isAvailable()){
return false;
}
$customerName = $customer->getName();
// some code goes here
}
}
class CustomerCardPrinterTest
{
public function testSuccessfulPrint()
{
$printer = $this->prophesize('\SomeNamespace\SomePackage\PrinterInterface');
$printer->isAvailable()->willReturn(true);
$customer = $this->prophesize('\SomeNamespace\SomeOtherPackage\CustomerInterface');
$customer->getName()->willReturn('SomeName');
$customerCardPrinter = new CustomerCardPrinter($someDriver->reveal(), $dummyPrinter->reveal());
$printResult = $customerCardPrinter->print();
$this->assertTrue($expectedResult, $testResult);
}
}
</code></pre>
</section>
<section>
<h2>Mock</h2>
<p class="left_align">
Define predictions (shouldBeCalled()), not promises
</p>
<p class="left_align">
Describing what will happen in the future
</p>
<p class="left_align">
Keeps track of method calls and their arguments
</p>
<p class="left_align">
Validates method calls given a certain set of expectations
</p>
</section>
<section>
<pre><code data-trim contenteditable>
class CustomerCardPrinter
{
private $printer;
private $customer;
public function __construct(PrinterInterface $printer, CustomerInterface $customer)
{
$this->printer = $printer;
$this->customer = $customer;
}
public function print()
{
if (! $this->printer->isAvailable()){
return false;
}
$customerName = $customer->getName();
// some code goes here
}
}
class CustomerCardPrinterTest
{
public function testSuccessfulPrint()
{
$printer = $this->prophesize('\SomeNamespace\SomePackage\PrinterInterface');
$printer->isAvailable()->shouldBeCalled()->willReturn(true);
$customer = $this->prophesize('\SomeNamespace\SomeOtherPackage\CustomerInterface');
$customer->getName()->shouldBeCalled()->willReturn('SomeName');
$customerCardPrinter = new CustomerCardPrinter($someDriver->reveal(), $dummyPrinter->reveal());
$printResult = $customerCardPrinter->print();
$this->assertTrue($expectedResult, $testResult);
}
}
</code></pre>
</section>
<section>
<h2>Spy</h2>
<p class="left_align">
Records behaviour
</p>
<p class="left_align">
Describing what has happened in the past
</p>
<p class="left_align">
Assertions happen afterwards (shouldHaveBeenCalled())
</p>
</section>
<section>
<pre><code data-trim contenteditable>
function it_notifies_an_attached_subscriber()
{
// arrange
$parser = new ParserSubject;
$event = $this->prophesize('Markdown\Event\Event')->reveal();
$subscriber = $this->prophesize('Markdown\Parser\Subscriber')->reveal();
// act
$parser->notify($event);
// assert
$subscriber->onChange($event)->shouldHaveBeenCalled();
}
</code></pre>
</section>
</section>
<section>
<section>
<img class="noframes" src="img/arrange_act_assert/advice.jpg">
</section>
<section>
<p class="left_align">
1. Try with writing tests after writing the code
<p class="left_align">
</section>
<section>
<p class="left_align">
2. When you get confidence try to write tests before the code
<p class="left_align">
</section>
<section>
<p class="left_align">
3. Treat test like your code - keep it "clean"
<p class="left_align">
<p class="fragment">
<ul>
<li>
Be descriptive about what you are testing
</li>
<li>
Do not duplicate test code
</li>
<li>
Do not make tests complex
</li>
</ul>
</p>
<aside class="notes">
Tests are clean if they are readable. What make them readable is clarity, simplicity and
density of expression - Clean Code - Robert C Martin
"What makes a clean test? Three things - Readability, readability, readability
Readability is even more important than in production code
Keep in mind that testing code is important as production code - maybe more important. It must
be clean as production code. Code changes and that means that your tests also changes - if you
write them bad than you have big problem - double problem. You are not safe anymore. You will start
writing code without tests.
Unit tests keep our code flexible, maintainable and reusable. Without them we loose everything.
With good tests we can improve architecture and design without having the fear of introducing
bugs.
</aside>
</section>
<section>
<p class="left_align">
4. Number of asserts in a test ought to be minimized
</p>
<aside class="notes">
One assert per test story...
Better use Single Concept per Test
</aside>
</section>
<section>
<p class="left_align">
5. Use Virtual Environments
</p>
<p class="left_align">
<img class="noframes" src="img/arrange_act_assert/vagrant_docker.png">
</p>
<aside class="notes">
</aside>
</section>
<section>
<p class="left_align">
6. Run tests often
</p>
<aside class="notes">
Run all your unit tests as often as possible, ideally every time the code is changed and
before any commit. Running tests often gives you confidence that your changes didn't break
anything and generally lowers the stress of programming in the dark. For larger systems,
you may just run specific test suites that are relevant to the code you're working on. Run
all your acceptance, integration, stress, and unit tests at least once per day (or night).
</aside>
</section>
<section>
<p class="left_align">
7. Test Boundary Conditions
</p>
<aside class="notes">
Take care about testing boundary values
</aside>
</section>
<section>
<p class="left_align">
8. Use test saboteurs (Humbug project)
</p>
<aside class="notes">
Mutation Testing is, in a nutshell, giving your unit tests a run for their money. It
involves injecting small defects into source code and then checking if the unit tests
noticed. If they do, then your unit tests have "killed" the mutation. If not, the mutation
has escaped detection. As unit tests are intended to prevent regressions, having a real
regression pass unnoticed would be a bad thing! Whereas Code Coverage can tell you what code
your tests are executing, Mutation Testing is intended to help you judge how well your unit
tests actually perform and where they could be improved.
</aside>
</section>
<section>
<p class="left_align">
9. Use test coverage
</p>
<p class="left_align">
<img class="noframes" src="img/arrange_act_assert/code-coverage.png">
</p>
<aside class="notes">
The higher code coverage makes your confidence also high - less fear of change
</aside>
</section>
<section>
<p class="red_text">
Test branch coverage not only code coverage
<pre><code data-trim contenteditable>
sampleMethod()
{
if (a < 5 and b > 10){
return a + b;
}
return $a - $b;
}
</code></pre>
</p>
</section>
<section>
<p class="left_align">
10. Test before refactoring
</p>
</section>
<section>
<p class="left_align">
11. Write unit tests for each bug you are going to fix
</p>
</section>
<section>
<p class="left_align">
12. Think twice before using New Operators - new ClassName()
</p>
</section>
<section>
<p class="left_align">
13. Think twice before using statics - SomeClass::someMethod()
</p>
</section>
<section>
<p class="left_align">
14. Avoid endless "anding" - Breaking SRP
</p>
</section>
<section>
<p class="left_align">
15. Avoid using switch-case often - use design patterns instead
</p>
</section>
<section>
<p class="left_align">
16. Avoid using too many dependencies - max 4 dependencies
</p>
</section>
<section>
<p class="left_align">
17. Avoid logic in constructor - only assign variables
</p>
</section>
<section>
<p class="left_align">
17. Do not break Law of Demeter
</p>
<pre><code data-trim contenteditable>
if ($account->getUser()->getRole()->IsAdmin()) {
return false;
}
</code></pre>
</section>
<section>
<p class="left_align">
18. Do Not Mock What You Do not Own
</p>
<aside class="notes">
Wrap 3rd party.
A framework or third party object often has to provide a large interface to solve a large
number of needs, of which you only need a subset. When you write your wrapper don't try and
write everything it does, write the operations you need, with the interface you want. If
you're using the language of your domain, rather than the language of the third party object,
this is much simpler.
</aside>
</section>
<section>
<p class="left_align">
19. Use data providers
</p>
<pre><code data-trim contenteditable>
/**
* @dataProvider getSuccessfulAddData
*/
public function testSuccessfulAdd($a, $b, $result)
{
$this->assertEquals($result,
$this->calculator->add($a, $b));
}
public function getSuccessfulAddData()
{
return [
['a' => 1, 'b' => 2, 'result' => 3],
['a' => 2, 'b' => 1, 'result' => 3],
['a' => 0, 'b' => 1, 'result' => 1],
['a' => 1, 'b' => 0, 'result' => 1],
];
}
</code></pre>
</section>
<section>
<p class="left_align">
20. Use continuous integration server
</p>
</section>
<section>
<p>