Automated tests - facts and myths

Automated tests
Facts and myths
Wojciech Sznapka / @sznapka

An introduction
I work in software industry for about 9 years
Care a lot about robust and testable architectures
Loves software craftsmanship, sophisticated architectures, Big Data
and ice hockey

Test Driven
Development
What is this?

You won’t go to hell if you’ll
write a test after declaring an
interface or prototyping a
class ...

... but you’ll surely end up in
hell, if there won’t be a test
coverage

Boss doesn't pay
for automated tests

It's a myth!
A 2005 study found that using TDD meant writing
more tests and, in turn, programmers who wrote
more tests tended to be more productive
by American Scientists

But this ain't that hard ...
casRmnovre
ls oaCnetr
{
poetd$ovrin =[
rtce cnesos
10 = '' 90= 'M,50= '' 40= 'D,10= ''
00 > M, 0 > C' 0 > D, 0 > C' 0 > C,
9 = 'C,5 = '' 4 = 'L,1 = ''
0 > X' 0 > L, 0 > X' 0 > X,
9= 'X,5= '' 4= 'V,1= '';
> I'
> V,
> I'
> I]
pbi fnto cnet$nrbc
ulc ucin ovr(iAai)
{
i (i_uei(iAai) {
f !snmrc$nrbc)
trwnwnaiAgmnEcpin' cnetnmrc';
ho e Ivldruetxeto(I ovr ueis)
}
i (iAai < 0 {
f $nrbc = )
rtr ';
eun '
}
ls (aai,$oa)=$hs>ovrinatro(iAai)
it $rbc rmn
ti-cnesoFcoFr$nrbc;
}

rtr $oa .$hs>ovr(iAai -$rbc;
eun rmn
ti-cnet$nrbc
aai)

poetdfnto cnesoFcoFr$nrbc
rtce ucin ovrinatro(iAai)
{
frah(ti-cnesosa $rbc= $oa){
oec $hs>ovrin s aai > rmn
i (aai < $nrbc {
f $rbc = iAai)
rtr [aai,$oa]
eun $rbc rmn;
}
}
}
}

... start from obvious things
casRmnovreTs etnsPPntFaeokTsCs
ls oaCnetret xed HUi_rmwr_etae
{
pbi fnto tsEpy)
ulc ucin etmt(
{
$hs>setqas',(e Rmnovre)>ovr(')
ti-asrEul(' nw oaCnetr-cnet');
}
}

... provide some meat ...
{
/*@aarvdrpoieetaa*
* dtPoie rvdTsDt /
pbi fnto tsCnesos$rbc $oa)
ulc ucin etovrin(aai, rmn
{
$ovre =nwRmnovre(;
cnetr
e oaCnetr)
$hs>setqas$oa,$ovre-cnet$rbc)
ti-asrEul(rmn cnetr>ovr(aai);
}

}

pbi fnto poieetaa)
ulc ucin rvdTsDt(
{
rtr ary
eun ra[
[47 'MCXVI]
39, MMDCI',
[,'',[,'I] [,'I] [,'X] [0 'L]
1 I] 2 I', 6 V', 9 I', 4, X',
[5 'L',[0 'C] [0,'',[0,'D]
4, XV] 9, X', 10 C] 40 C'
]
;
}

... test edge cases
{
/*@xetdxeto naiAgmnEcpin*
* epceEcpin Ivldruetxeto /
pbi fnto tsEpy)
ulc ucin etmt(
{
(e Rmnovre)>ovr(wfIa psighr')
nw oaCnetr-cnet't
m asn ee);
}
}

Help yourself with tests generation
ppntsegn-ts Rmnovre
hui-kle -et oaCnetr

... or using Symfony's
XSolveUnitSkelgenBundle
.apcnoexov:kle:etAm/xmlBnl/evc/
/p/osl slesegnts ceEapeudeSrie.
.apcnoexov:kle:etAm//otolr*
/p/osl slesegnts ce*Cnrle/

We are building
too complicated
system
for an automated tests

TDD forces you to write
cleaner code

It's easier to test smaller units
of code

so you write smaller classes
which are less coupled
and that makes your system more stable
and open for an extension in the future

Your Object Oriented design
becomes S.O.L.I.D. compilant
and this is awesome!

You will of course tackle
costly dependencies

Use PHPUnit's mock
framework or Mockery

Fake it till you make it
casMceTs etnsPPntFaeokTsCs
ls okdet xed HUi_rmwr_etae
{
pbi fnto tsNnxsigauOjcs)
ulc ucin etoEitnVlebet(
{
$ofgrto =okr:mc(ofgrtoVlebet,[
cniuain
Mcey:ok'CniuainauOjc'
'eUl = 'tp/tdsnpap'
gtr' > ht:/d.zak.l,
'eFra'= 'm')
gtomt > xl];
$hs>setqas'm' $ofgrto-gtomt);/ O
ti-asrEul(xl, cniuain>eFra() / K
}
}

Mock things
that can't be tested quickly or nonreproducable
{
pbi fnto tsAial(
ulc ucin etpCls)
{
$uzok okr:mc(uzBosr)
bzMc= Mcey:ok'Bzrwe';
$uzok>hudeev(gt)
bzMc-solRcie'e'
-adeun'rsos>mo>wsmt<mo>/epne';
>nRtr(<epne<odAeoiy/od<rsos>)
/ ti as i ws slto,t wiexlfxue i fl
/ hs lo s ie ouin o rt m itrs n ie
/ $uzok>hudeev(gt)>ne)
/ bzMc-solRcie'e'-oc(
/
/
-adeunfl_e_otns_DR_.'fxue.m')
>nRtr(iegtcnet(_I_
/itrsxl);

}

}

$p =nwpCnue(bzMc)
ai
e Aiosmr$uzok;
$p-asrEul(Aeoiy,$p-gturnMo() / O
ai>setqas'wsmt' ai>eCretod); / K

Expect declared behaviors
{
pbi fnto tsEpcainDcaain(
ulc ucin etxettoselrtos)
{
$uzok>hudeev(gt)
bzMc-solRcie'e'
-adeun'rsos>mo>wsmt<mo>/epne';
>nRtr(<epne<odAeoiy/od<rsos>)
$ogrok=okr:mc(oooogr)
lgeMc
Mcey:ok'MnlgLge';
/ w js wn t b sr ta Lge:if wscle ol oc
/ e ut at o e ue ht ogr:no a ald ny ne
$ogrok>hudeev(if'-oc(;
lgeMc-solRcie'no)>ne)

}

}

$p =nwpCnue(bzMc,$ogrok;
ai
e Aiosmr$uzok lgeMc)
$p-asrEul(Aeoiy,$p-gturnMo() / O
ai>setqas'wsmt' ai>eCretod); / K

Be prepared for failures
and check if you prepared for unexpected situations
{
/*@xetdxeto yxetoWapr*
* epceEcpin MEcpinrpe /
pbi fnto tsFieCneto(
ulc ucin etaldoncin)
{
$uzok>hudeev(gt)
bzMc-solRcie'e'
-adho(uzEcpinCinEcpin)
>nTrw'Bzxetoletxeto';
$ogrok=okr:mc(oooogr)
lgeMc
Mcey:ok'MnlgLge';
$ogrok>hudeev(if'-nvr)
lgeMc-solRcie'no)>ee(;
$ogrok>hudeev(er)>ne)
lgeMc-solRcie'r'-oc(;

}

}

(e pCnue(bzMc,$ogrok)>eCretod)
nw Aiosmr$uzok lgeMc)-gturnMo(;

We providing
API for external
consumers
it can't be tested...

Use Symfony's WebTestCase
to test your API
I call it integration tests

Call your API and check if it
returns prepared data
casEpniueotolretetnsWbetae
ls xedtrCnrleTs xed eTsCs
{
ueIoaeTssri;/ i rst ts evrnet
s sltdetTat / t ees et niomn
pbi fnto tsGtitnsn)
ulc ucin eteLsIJo(
{
$let=sai:cetCin(;
cin
ttc:raelet)
$let>eus(GT,'epniue.sn)
cin-rqet'E' /xedtrsjo';
$sn=jo_eoe$let>eRsos(-gtotn()
jo
sndcd(cin-gtepne)>eCnet);

}

}

$hs>setre$let>eRsos(-iScesu()
ti-asrTu(cin-gtepne)>sucsfl);
$hs>seton(0 $sn;
ti-asrCut8, jo)
$hs>setraeTaOEul
ti-asrGetrhnrqa(
nwaeie$sn7]>rae_t,
e DtTm(jo[9-cetda)
nwaeie$sn0-cetda);
e DtTm(jo[]>rae_t)

Use fixtures and reset
environment
IsolatedTestsTrait should do the trick

Steps required to effectively
run in isolation
1.
2.
3.
4.
5.
6.
7.

configure PDO SQLite in file
create database
drop schema
load fixtres
copy database as a backup
copy database from backup for every test
delete database backup after test suite

Requirements
changes
frequently
we can't keep up with unit
tests

Use behavioral
approach
Behat in PHP

Describe features as scenarios
It will be readable for: business, developers and machines

Perfectly fits into Agile
process

Simple example
Faue lo frajb
etr: ok o
o
I odrt fn co jb
n re o id ol o
A a aprn porme
s n siig rgamr
Ine t b al t ls jbofr
ed o e be o it o fes
Seai:ls ofr frP vrin
cnro it fes o L eso
GvnIa o ""
ie
m n /
Te Isol se"oązd tau
hn
hud e Dłc o em"
Adcik"oązd tau
n lc Dłc o em"
Te Isol b o "krea
hn
hud e n /air"
AdIsol se"H Sno Dvlpr(lwc)
n
hud e PP eir eeoe Giie"
Seai:n ofr frE st
cnro o fes o N ie
GvnIa o "e"
ie
m n /n
Te Isol ntse"oązd tau
hn
hud o e Dłc o em"
AdIsol ntsea "ji-s eeet
n
hud o e n #onu" lmn

Always use in-memory sqlite
database
Or create clean sqlite database and copy
it for every test

Group your tests
Use PHPUnit's @group or Behat's @tag

Create "smoke tests" groups
Those should be fast test, which ensures your system is most likely
stable

Slower tests should run during
night

It gives you confidence
about changes and your code

Team is able to rapidly
experiment with code

TDD enforces better
Object Oriented design
Smaller units of code and lower coupling always leads to better
understanding of the codebase by future devs

End user experiences better
quality
lower 500 error ratio in the production

Happier users
↓
more $$$ in future

Setting up an working
environment for automated
tests
is timely costly at the begining, but it pays off in the future

System without any kind of
automated tests
has big potential to be a big ball of mud

Good coverage can be easily
achieved with
mix of unit, functional and behavioral tests

You need to build and
cultivate
TDD culture in your surrounding

Thank you so much for
attending!
Feedback is much appreciated
wojciech@sznapka.pl
Twitter: @sznapka
GitHub: @wowo

Automated tests - facts and myths

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