Transcript
How to Use Ceedling for Embedded Test-Driven Development with Step-by-Step Examples Matt Chernosky http://electronvector.com
Copyright © 2!" Matt Chernosky. #ll rights reser ve$.
Contents %elcome..........................................................................................................................................................................& %hat is 'est-(riven (evelopment )'((*+.........................................................................................................., 'he 'ools.......................................................................................................................................................................... nstalling Cee$ling......................................................................................................................................................." Creating a ew Cee$ling 0ro1ect........................................................................................................................... Example 3!: Starting '(( with Cee$ling............................................................................................................4 Create a Mo$5le......................................................................................................................................................4 mplement a 6eat5re...........................................................................................................................................!! 7epeat.......................................................................................................................................................................!& 7e8actoring..............................................................................................................................................................! Mocking 9ar$ware nter8aces...............................................................................................................................! Example 32: Mocking a 9ar$ware nter8ace with CMock..........................................................................!4 Create the 'emperat5re Sensor Mo$5le.....................................................................................................!4 %rite 5r 6irst 'est..............................................................................................................................................!4 Create the 65nction ;n$er 'est......................................................................................................................2! Mock the 2C nter8ace.......................................................................................................................................2! mplement the 65nction ;n$er 'est.............................................................................................................22 #$$ing #nother 'est...........................................................................................................................................22 7e8erences....................................................................................................................................................................2, So5rce Co$e...........................................................................................................................................................2, (oc5mentation.....................................................................................................................................................2, Cee$ling <5ick 7e8erence......................................................................................................................................2 'est #ssertions.......................................................................................................................................................2 Mock 65nction 6ormats.....................................................................................................................................2"
How to Use Ceedling for Embedded Test-Driven Test-Driven Development
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Welcome Maybe yo5=ve hear$ o8 Test-Driven Development )'((*> an$ maybe yo5=ve even tho5ght it seeme$ like a reasonable i$ea. If you havent tried TDD yet though! you really should" 'his g5i$e contains step-by-step examples to get yo5 starte$ test $riving in C> especially 8or embe$$e$ so8tware applications. %e=ll look at how to 5se the 5nit test 8ramework calle$ Cee$ling to help 5s $o this. n the 8irst example> we=ll see how to create tests an$ write the co$e to make them pass. n the secon$ example we look at mocking> an$ learn how to 5se it sim5late o5r har$ware. #ll the tests in these examples compile an$ r5n on yo5r host 0C )with ?CC*> with no target har$ware nee$e$.
How to Use Ceedling for Embedded Test-Driven Development
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What is Test-Driven Development #TDD$% 'he premise o8 '(( is that we 5se the creation o8 5nit tests to incrementally $rive the $evelopment o8 the so8tware. 'he steps look like: !. %rite a test> an$ watch it 8ail. 2. mplement 15st eno5gh co$e to make the test pass. &. 7e8actor. ,. 7epeat. 'his allows 5s to be very clear abo5t what the co$e is to $o> beca5se we=ve $e8ine$ every behavior in a test. %ith each iteration yo5 a$$ a bit more 85nctionality to yo5r so8tware> an$ the tests give yo5 con8i$ence that yo5=re $oing it correctly. ne o8 the $i88ic5lties o8 5nit testing is that it takes some $egree o8 experience to write testable co$e. 8 yo5 write the tests 8irst tho5gh> yo5=ll 8ig5re o5t how to make yo5r co$e testable while yo5 write it. 'his means yo5 won=t waste yo5r time with this problem at all@ 6or me> the greatest aspect o8 '(( is that it takes a big problem to solve )how to implement a so8tware application* an$ re$5ces it to a simple problem )what is the next little thing nee$ this so8tware to $o*. 'hen 15st write a test 8or that 8eat5re> implement it an$ repeat. Ao5 simply stop when yo5 $on=t nee$ any more 8eat5res. #n$ when yo5 $o stop> yo5=re con8i$ent that what yo5 have is working exactly how yo5 want it to. t=s 5nlikely that yo5=ll be spen$ing a lot o8 time chasing $own b5gs.
How to Use Ceedling for Embedded Test-Driven Development
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The Tools 'he testing tools 5se$ in this example are Cee$ling> ;nity an$ CMock. 'hese are the best C 5nit test tools available> 8rom the people over at http://www.throwtheswitch.org/ . Cee$ling is an a5tomate$ testing 8ramework 8or C applications. t=s b5ilt aro5n$ 7ake> which is the 75by programming lang5age=s b5il$ tool. 'hat=s why all o8 the BCee$ling comman$s are act5ally 7ake comman$s. n or$er to $o '((> yo5 nee$ to be able to create an$ r5n tests easily since yo5=ll be $oing it all the time. Cee$ling provi$es a5tomatic test $iscovery> mock generation an$ test exec5tion> which makes it the best option 8or 5nit testing in C. t also b5il$s an$ r5ns tests on the host 0C> so when working on an embe$$e$ pro1ect we $on=t have to waste time $ownloa$ing to the target. ;nity is the 5nit test 8ramework provi$e$ with Cee$ling. t gives 5s all o8 o5r test assertions constr5cting o5r tests. CMock is the mocking 8ramework 5se$ with Cee$ling. 'he mocking 8ramework is what lets 5s sim5late interactions with other so8tware mo$5les> so that we can test o5r so8tware 5nits in isolation.
How to Use Ceedling for Embedded Test-Driven Development
Installing Ceedling Cee$ling reD5ires 75by to r5n an$ 5ses ?CC to b5il$ each test. !. nstall 75by %in$ows installer: https://$l.bintray.com/oneclick/r5byinstaller/r5byinstaller-2.&.!.exe ther instr5ctions: https://www.r5by-lang.org/en/$oc5mentation/installation/ . &e sure that the 'uby bin folder is in your path> e.g. C:75by2&bin 2. nstall Cee$ling with the 75by FgemF tool with the comman$: gem install ceedling Installation Error: “certificate verify failed” I’ve recently had an issue trying to use the gem! command" It’s a problem with the #uby$ems server %where Ceedling and other gems are hosted&" If you get an error li'e this( ERROR: Could not find a valid gem 'ceedling' (>= 0), here is wh: !na"le to download data from htt#s:$$ru"gems%org$ & connect returned=* errno=0 state=v+ read server certificate : certificate verif failed ( https://api.rubygems.org/specs.4.8.gz)
The )uic' fi* is to install a new certificate into #uby" Download this certificate file( https(++raw"githubusercontent"com+rubygems+rubygems+master+lib+rubygems+ssl,c erts+inde*"rubygems"org+$lobalign#ootC."pem and place it into C:\Ruby23\lib\ruby\2.3.0\rubygems\sslcerts" /ote that your path may be different if you installed to another folder or installed a different version" &. 8 yo5=re on %in$ows> yo5=ll likely nee$ to install ?CC. recommen$ installing with Cygwin )https://cygwin.com/install.html*. %hen installing be s5re to select the F(evelF packages to have ?CC installe$. 'hen p5t the Cygwin bin 8ol$er in yo5r path> e.g. C:cygwin",bin.
How to Use Ceedling for Embedded Test-Driven Development
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Creating a (ew Ceedling )ro*ect ;se the Gcee$ling new Hpro1ectameIG comman$ to create a new pro1ect: $ ceedling new MyProject create
MyProject/vendor/ceedling/docs/eedlingPac!et.pd"
create MyProject/vendor/ceedling/docs/#ception%ummary.pd" ... create MyProject/vendor/ceedling/vendor/unity/src/unity.h create MyProject/vendor/ceedling/vendor/unity/src/unity&internals.h create
MyProject/project.yml
create
MyProject/ra!e"ile.rb
Project 'MyProject' created( ) *ool documentation is located in vendor/ceedling/docs ) #ecute 'ra!e )*' to view available test + build tas!s
'his generates a pro1ect tree an$ the con8ig5ration 8iles nee$e$ to 5se Cee$ling. 0ro1ect creation only nee$s to be $one once when starting a pro1ect. mportant among the create$ 8ol$ers are: •
src: %here all o8 o5r so5rce 8iles will go.
•
b5il$: Contains anything generate$ by Cee$ling $5ring the b5il$.
•
test: %here o5r 5nit test 8iles will go.
ow we have a pro1ect in the GMy0ro1ectG 8ol$er. ote the instr5ctions 8rom the Cee$ling o5tp5t when we create$ the pro1ect -- we can 5se Grake -'G to show 5s how to 5se it: $ cd MyProject $ ra!e )* ra!e clean temporar...
, -elete all build arti"acts and
ra!e clobber build a...
, -elete all generated "iles and
ra!e environment variables
, ist all con"igured environment
ra!e "iles:header
, ist all collected header "iles
ra!e "iles:source
, ist all collected source "iles
ra!e "iles:test
, ist all collected test "iles
ra!e logging
, #nable logging
How to Use Ceedling for Embedded Test-Driven Development
ra!e module:create0module&path1 and tes...
, 2enerate module source3 header
ra!e module:destroy0module&path1 and test...
, -estroy module source3 header
ra!e paths:source
, ist all collected source paths
ra!e paths:support
, ist all collected support paths
ra!e paths:test
, ist all collected test paths
ra!e summary no bui...
, #ecute plugin result summaries
ra!e test: or sourc...
, 5un single test 01 real test
ra!e test:all
, 5un all unit tests
ra!e test:delta
, 5un tests "or changed "iles
ra!e test:path0dir1 contains 0dir...
, 5un tests whose test path
ra!e test:pattern0rege1 epressio...
, 5un tests by matching regular
ra!e verbosity0level1 obnoi...
, %et verbose output silent:061 )
ra!e version version in"o
, -isplay build environment
Cee$ling is b5ilt on 7ake> which is 75by=s $epen$ency-base$ b5il$ tool. Cee$ling an$ its 5nit test operations are implemente$ as ra+e tas+s. 'hese are the comman$s we will 5se to b5il$ an$ r5n o5r tests. /ote( ince we0re using #a'e we can e*tend our build capabilities by adding our own ra'e tas's to do whatever we would li'e1 e"g" generating documentation or downloading to the target"
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E,ample ./ 0tarting TDD with Ceedling n this example we=ll walk thro5gh a single '(( micro-cycle> a$$ing a 8eat5re by writing a test an$ getting it to pass. /ote that a new Ceedling pro2ect must have been created as described in the previous section"
Create a 1odule ow it=s time to write some co$e. magine we=re b5il$ing a car an$ we want to b5i l$ a mo$5le to implement the lighting system. %e create a mo$5le like this: $ ra!e module:create0lights1 2enerating 'lights'... m!dir )p ./test/. m!dir )p ./src/. 7ile ./test/./test&lights.c created 7ile ./src/./lights.c created 7ile ./src/./lights.h created
'his creates three 8iles: Glights.cG to implement o5r mo$5le> Glights.hG to $e8ine the p5blic inter8ace an$ a test 8ile where we can p5t the 5nit tests 8or it. 'hese 8iles are a5tomatically create$ in the correct 8ol$ers o8 o5r tree. /ote( 3e could also have provided a deeper path in which to create the module1 e"g" ra-e module:create.electrical$lights/" #t this point> we can try r5nning o5r 5nit tests: $ ra!e test:all *est 'test&lights.c' )))))))))))))))))))) 2enerating runner "or test&lights.c... ompiling test&lights&runner.c... ompiling test&lights.c... ompiling unity.c... ompiling lights.c... ompiling cmoc!.c... in!ing test&lights.out... 5unning test&lights.out...
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))))))))))) *#%* 9*P9* ))))))))))) 0test&lights.c1 )))))))))))))))))))) ;2<5#- *#%* %9MM=5> )))))))))))))))))))) 0test&lights.c1 *est: test&module&generator&needs&to&be&implemented =t line ?4@: ;mplement me( )))))))))))))))))))) A#5= *#%* %9MM=5> )))))))))))))))))))) *#%*#-:
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'his tells 5s that a single test was r5n an$ it was ignored . 'he module:create task has 5se$ a template to create the test 8ile. nsi$e the test 8ile testKlights.c is a single test name$ test&module&generator&needs&to&be&implemented which 5ses a special ignore $irective to tell Cee$ling to ignore this test. 'he 85nction looks like this: void test&module&generator&needs&to&be&implementedvoid@ B *#%*&;2<5#&M#%%=2#;mplement me(@C D
'his is the convention 8or 5nit tests which Cee$ling. 'est 8iles have names that start with test& an$ they go in the Btest 8ol$er. %ithin each o8 these 8iles> 5nit tests are 85nctions whose names start with test&. #lso in the test 8ile are the set9p@ an$ tear-own@ 85nctions. 'hese 85nctions are r5n be8ore an$ a8ter each o8 the test 85nctions in the test 8ile. 'hese 85nctions are yo5rs to 5se i8 yo5 nee$ them.
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Implement a 2eature ow that we have a mo$5le 8or the lights> it=s time to a$$ some 85nctionality. n the test$riven way> we=ll 8irst a$$ a test that $escribes some $esire$ behavior. Say we want this behavior: 3hen the headlight switch is off1 then the headlights are off" n this case we=re going to replace test&module&generator&needs&to&be&implemented@ with a new test 85nction: void test&Ehen*heFeadlight%witch;s""&*hen*heFeadights=re""void@ B // Ehen the headlight switch is o""... lights&%etFeadlight%witch""@C // then the headlights are o"". *#%*&=%%#5*&#G9="alse3 lights&=reFeadlightsn@@C D
%hat we=ve $one here is $e8ine two new 85nctions to implement in the lights mo$5le> lights&%etFeadlight%witch""@ an$ lights&=reFeadlightsn@. %e call the 8irst 85nction to t5rn the lights o88> an$ then call the secon$ to con8irm the state o8 the hea$li ghts. 'he *#%*&=%%#5*&#G9=@ macro is what we 5se to veri8y that the val5e ret5rne$ 8rom lights&=reFeadlightsn@ is the expecte$ val5e )"alse*. 'his is one o8 the many macros available 8or comparing vario5s types> all o8 which are explaine$ in the ;nity $oc5mentation )https://gith5b.com/'hrow'heSwitch/;nity/blob/master/$ocs/;nityL2S5mmary.p$8 *. ow we can r5n o5r tests> b5t obvio5sly this is going to 8ail with all kin$s o8 compilation errors> beca5se these 85nctions $on=t even exist yet. $ ra!e test:all *est 'test&lights.c' )))))))))))))))))))) 2enerating runner "or test&lights.c... ompiling test&lights&runner.c... ompiling test&lights.c... ... H %hell eecuted command: 'gcc.ee );test );test/support );src
);MyProject/vendor/ceedling/vendor/unity/src
How to Use Ceedling for Embedded Test-Driven Development
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);MyProject/vendor/ceedling/vendor/cmoc!/src );build/test/moc!s )-*#%* )-2<9&MP;#5 )g )c test/test&lights.c )o build/test/out/test&lights.o'
H =nd eited with status: 0?1. ra!e aborted( ... *as!s: *P IH build/test/results/test&lights.pass IH
build/test/out/test&lights.
out IH build/test/out/test&lights.o %ee "ull trace by running tas! with ))trace@ )))))))))))))))))))) A#5= *#%* %9MM=5> )))))))))))))))))))) )))))))))))))))))))) *#%*#-:
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'his may sort o8 8eel like we=re cheating> since lights&%etFeadlight%witch""@ $oesn=t act5ally $o anything an$ lights&=reFeadlightsn@ simply ret5rns "alse> b5t as we a$$ more tests we=ll contin5e to a$$ 85nctionality.
'epeat %e can now contin5e a$$ing B8eat5res to the mo$5le 5ntil it $oes every thing that we nee$ it to -- by a$$ing tests an$ then writing the co$e to make them pass. 6or example might want to implement this behavior: 3hen the headlight switch is on1 then the headlights are on" How to Use Ceedling for Embedded Test-Driven Development
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So> we create an a$$itional test: void test&Ehen*heFeadlight%witch;sn&*hen*heFeadights=renvoid@ B // Ehen the headlight switch is on... lights&%etFeadlight%witchn@C // then the headlights are on. *#%*&=%%#5*&#G9=true3 lights&=reFeadlightsn@@C D
8 we r5n this test it will 8ail beca5se lights&%etFeadlight%witchn@ $oesn=t exist yet> b5t when we 5p$ate lights.h: ,i"nde" lights&F ,de"ine lights&F ,include Jstdbool.hH void lights&%etFeadlight%witch""void@C void lights&%etFeadlight%witch""void@C bool lights&=reFeadlightsnvoid@C ,endi" // lights&F
#n$ a$$ the implementation in lights.c: ,include lights.h ,include Jstdbool.hH static bool areightsn I "alseC void lights&%etFeadlight%witch""void@ B areightsn I "alseC D void lights&%etFeadlight%witchnvoid@ B areightsn I trueC
How to Use Ceedling for Embedded Test-Driven Development
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D bool lights&=reFeadlightsnvoid@ B return areightsnC D
'hen we can r5n o5r tests an$ watch them both pass: $ ra!e test:all *est 'test&lights.c' )))))))))))))))))))) 2enerating runner "or test&lights.c... ompiling test&lights&runner.c... ompiling test&lights.c... in!ing test&lights.out... 5unning test&lights.out... ))))))))))) *#%* 9*P9* ))))))))))) 0test&lights.c1 K )))))))))))))))))))) A#5= *#%* %9MM=5> )))))))))))))))))))) *#%*#-:
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'efactoring Every time we get a test to pass> is an opport5nity to re8actor. Since we have a s5ite o8 passing tests> we can change the co$e in any way an$ we=ll imme$iately know i8 we broke something. 'his allows 5s the ability to 8reely experiment with improving the co$e> e.g. to make it simpler or easier to 5n$erstan$.
How to Use Ceedling for Embedded Test-Driven Development
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7e8actoring can also be $one to the tests as well. Ao5 may notice that as yo5 a$$ more an$ more tests> some become re$5n$ant or yo5 en$ 5p with a lot o8 $5plication across tests. Ao5=ll want to keep this 5n$er control as yo5 work> so that they tests $on=t get too $i88ic5lt to 5n$erstan$.
How to Use Ceedling for Embedded Test-Driven Development
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1oc+ing Hardware Interfaces 9ow can yo5 5nit test yo5r embe$$e$ so8tware+ %hat abo5t yo5r har$ware $epen$encies+ 'he secret is moc'ing" %e can mock the inter8aces to o5r har$ware so that we dont need the actual hardware to test. 'his allows 5s to r5n o5r tests more D5ickly an$ be8ore the har$ware might even be available. 8 we=re $eveloping the so8tware 8or an embe$$e$ microcontroller> we=re probably going to be 5sing the microcontroller-provi$e$ har$ware mo$5les 8or things like S0> 2C> timers> etc.
6or each o8 these har$ware inter8aces> we want to have a correspon$ing so8tware mo$5le containing the microcontroller har$ware $epen$encies )i.e. har$ware register accesses*.
How to Use Ceedling for Embedded Test-Driven Development
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%e can then mock each o8 these har$ware inter8aces> eliminating o5r har$ware $epen$encies b5t still allowing 5s to 5nit test o5r application. nstea$ o8 compiling these tests 8or the embe$$e$ microcontroller> we compile them 8or an$ r5n them on o5r host 0C.
'o help yo5 create yo5r mocks yo5 want to 5se a moc'ing framewor' . 'he mocking 8ramework incl5$e$ with Cee$ling is CMock. t allows yo5 to create mocks o8 in$ivi$5al so8tware mo$5les 8rom their hea$er 8iles. Ceedling improves the e,perience by automatically using C1oc+ to generating the moc+s that we need"
How to Use Ceedling for Embedded Test-Driven Development
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E,ample 3/ 1oc+ing a Hardware Interface with C1oc+ /ote that this e*ample assumes that we already have an e*isting Ceedling pro2ect" ee the section titles Creating a /ew Ceedling 4ro2ect if you need help" magine that we want to talk to an external 2C temperat5re sensor.
Create the Temperature 0ensor 1odule et=s create a mo$5le that will be o5r temperat5re sensor $river. $ ra!e module:create0temp%ensor1 2enerating 'temp%ensor'... m!dir )p ./test/. m!dir )p ./src/. 7ile ./test/./test&temp%ensor.c created 7ile ./src/./temp%ensor.c created 7ile ./src/./temp%ensor.h created
Write 4ur 2irst Test %hat is the 8irst thing want to be able to $o with this sensor+ =$ like to be able to rea$ the c5rrent temperat5re val5e. Cool. So take a look at the $atasheet 8or my 8ictional temperat5re sensor an$ can see that it How to Use Ceedling for Embedded Test-Driven Development
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has a b5nch o8 !"-bit registers -- each with J-bit a$$resses -- one o8 which is the temperat5re register. 'he scaling o8 the val5es is s5ch that a register val5e o8 is -!.NC an$ a register val5e o8 x&66 is O!,."NC. 'his makes each bit eD5ivalent to .2NC.
ow lets a$$ o5r 8irst test to testKtempSensor.c. want to know that when rea$ a temperat5re register val5e o8 x&66 that the temperat5re calc5late$ is !,.". void test&when*emp5egister5eadsMaAalue&then*he*emp;s*heMaAaluevoid@ B uint8&t temp5egister=ddress I 66C "loat epected*emperature I ?64.N"C "loat tolerance I 6.?"C //Ehen iLc&read5egister&#pect=nd5eturntemp5egister=ddress3 6""@C //*hen "loat actual*emperature I temp%ensor&get*emperature@C *#%*&=%%#5*&7=*&E;*F;<tolerance3 epected*emperature3 actual*emperature@C D
6irst we set 5p some variables to hol$ o5r expecte$ val5es. 'hen in the FwhenF cla5se> we nee$ to sim5late )or mock* the 2C mo$5le ret5rning a val5e o8 x&88 on a rea$ o8 the temperat5re a$$ress. 6or the moment> we preten$ that there is another i2c mo$5le )it $oesn=t act5ally exist yet* which han$les the 2C comm5nication with the temperat5re sensor. 'his is where o5r har$ware $epen$ent co$e will event5ally go. So> the iLc&read5eadgister&#pect=nd5eturn 85nction is act5ally a mock 85nction 5se$ to sim5late a call to a 85nction calle$ iLc&read5egister in the i2c mo$5le. %e=ll come back to this in a moment.
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'he FthenF cla5se is where we test that the tempSensor mo$5le act5ally ret5rns the correct temperat5re when we call temp%ensor&get*emperature. 'his 85nction $oesn=t exist yet either.
Create the 2unction Under Test ets create the temp%ensor&get*emperature 85nction with a $5mmy implementation: tempSensor.h: , i"nde" temp%ensor&F , de"ine temp%ensor&F "loat temp%ensor&get*emperaturevoid@C , endi" // temp%ensor&F
tempSensor.c: , include temp%ensor.h "loat temp%ensor&get*emperaturevoid@ B return 6.6"C D
1oc+ the I3C Interface 8 we try an$ r5n the test now> the compiler will complain that it $oesn=t know abo5t the iLc&read5eadgister&#pect=nd5eturn mock 85nction. 'his is beca5se the iLc&read5egister 85nction $oesn=t exist an$ we haven=t yet tol$ Cee$ling to mock it. We dont actually need to implement this function however" Its enough to declare the function prototype in a header file and tell Ceedling to moc+ it with C1oc+" Create the hea$er 8ile> i2c.h: , i"nde" iLc&F , de"ine iLc&F , include Jstdint.hH uint?N&t iLc&read5egisteruint8&t register=ddress@C
How to Use Ceedling for Embedded Test-Driven Development
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, endi" // iLc&F
'he way we tell Cee$ling to mock this mo$5le is to a$$ this line to testKtempSensor.c: , include moc!&iLc.h
'his tells Cee$ling: 5ou 'now the i6c"h header you see over there7 3ell""" use C8oc' to generate the implementation and compile it in for us1 o'ay7 %hen CMock gets a hol$ o8 the hea$er 8ile it looks at all the 85nctions $e8ine$ there an$ generates several mock 85nctions 8or each... incl5$ing the iLc&read5egister&#pect=nd5eturn 85nction we 5se$ in the test. 'his mock 85nction appen$s an a$$itional arg5ment to the original iLc&read5egister 85nction> which is the val5e we want the 85nction to ret5rn to the calling 85nction. 6or more $etails on all the mock 85nctions available with CMock> see the CMock $oc5mentation at: https://gith5b.com/'hrow'heSwitch/CMock/blob/master/$ocs/CMockKS5mmary.m$3generat e$-mock-mo$5le-s5mmary.
Implement the 2unction Under Test ow we can implement the logic 8or o5r temp%ensor&get*emperature 85nction. 5r new tempSensor.c is: , include temp%ensor.h , include iLc.h , include Jstdint.hH "loat temp%ensor&get*emperaturevoid@ B uint?N&t rawAalue I iLc&read5egister66@C return )?66.6" K 6.L" "loat@rawAalue@C D
8 we r5n o5r test> it sho5l$ pass now.
5dding 5nother Test %e=ll next want to a$$ more tests 8or other possible ret5rn val5es 8rom iLc&read5egister. 'his is easily $one by changing the ret5rn val5e provi$e$ to the mock 85nction. How to Use Ceedling for Embedded Test-Driven Development
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6or example> to test that the minim5m temperat5re val5e is rea$ correctly: void test&when*emp5egister5eadsMinAalue&then*he*emp;s*heMinAaluevoid@ B uint8&t temp5egister=ddress I 66C "loat epected*emperature I )?66.6"C "loat tolerance I 6.?"C //Ehen iLc&read5egister&#pect=nd5eturntemp5egister=ddress3 66@C //*hen "loat actual*emperature I temp%ensor&get*emperature@C *#%*&=%%#5*&7=*&E;*F;<tolerance3 epected*emperature3
actual*emperature@C
D
(ow we have a driver for an e,ternal hardware device that we can test without any of the hardware" %e can contin5e to $evelop the $river -- a$$ing more tests an$ 8eat5res -- by b5il$ing an$ testing on o5r host 0C. Py p5tting all o8 the microcontroller-$epen$ent 2C operations into their own mo$5le> we easily mocke$ them with Cee$ling an$ CMock. n 8act> we $i$n=t even have to implement this mo$5le yet -- we 15st ha$ to $e8ine its inter8ace in the hea$er 8ile. ;sing o5r mocks> we create$ 5nit tests that veri8y the behavior o8 o5r temperat5re sensor $river. 5s the rest of our application is developed! we can easily run these unit tests at any time to ma+e sure the driver will still wor+ correctly"
How to Use Ceedling for Embedded Test-Driven Development
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'eferences 0ource Code 'he so5rce co$e 5se$ in these examples is available on ?it95b. E,ample .
https://gith5b.com/ElectronQector/try-t$$-with-cee$ling
E,ample 3
https://gith5b.com/ElectronQector/mocking-har$ware-cee$ling-cmock
Documentation Ceedling
https://gith5b.com/'hrow'heSwitch/Cee$ling/blob/master/$ocs/Cee$ling0 acket.m$
Unity
https://gith5b.com/'hrow'heSwitch/;nity
C1oc+
https://gith5b.com/'hrow'heSwitch/CMock/blob/master/$ocs/CMockKS5m mary.m$
How to Use Ceedling for Embedded Test-Driven Development
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Ceedling 6uic+ 'eference ceedling new Jproject)nameH
Create a new Cee$ling pro1ect name$ Jproject)nameH.
ra!e )*
Show all available rake )Cee$ling* tasks 8or the pro1ect.
ra!e module:create0Jmodule)nameH1
Create a new mo$5le name$ Jmodule)nameH. Creates a so5rce 8ile> hea$er 8ile an$ 5nit test 8ile.
ra!e module:destroy0Jmodule)nameH1
(elete an existing mo$5le name$ Jmodule) nameH.
ra!e test:all
75n all 5nit tests in the pro1ect.
ra!e test:Jmodule)nameH
75n only the 5nit tests 8or this mo$5le.
ra!e clobber
(elete everything create$ $5ring the b5il$ o8 the tests. ike cleaning> b5t more.
Test 5ssertions *#%*&=%%#5*condition@
0ass i8 the con$ition is tr5e.
*#%*&=%%#5*&*59#condition@
0ass i8 the con$ition is tr5e.
*#%*&=%%#5*&7=%#condition@
0ass i8 the con$ition is 8alse.
*#%*&7=;@
6ail the test imme$iately.
*#%*&;2<5#@
# test containing this statement is ignore$.
*#%*&=%%#5*&7=*&E;*F;< delta3 epected3 actual@
0ass i8 the two 8loat val5e are within delta o8 each other.
*#%*&=%%#5*&#G9=&%*5;<2 epected3 actual@
0ass i8 the two n5ll-terminate$ strings match.
*#%*&=%%#5*&#G9=&%*5;<2&#< epected3 actual3 len@
0ass i8 the two strings match 5p to len.
How to Use Ceedling for Embedded Test-Driven Development
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*#%*&=%%#5*&<9pointer@
0ass i8 the pointer is a n5ll pointer.
*#%*&=%%#5*&<*&<9pointer@
0ass i8 the pointer is not a n5ll pointer.
*#%*&=%%#5*&#G9=&M#M5> epected3 actual3 len@
0ass i8 the two regions o8 memory match.
*#%*&=%%#5*&#G9=&;<* epected3 actual@
0ass i8 the two signe$ integers match.
*#%*&=%%#5*&#G9=&9;<* epected3 actual@
0ass i8 the two 5nsigne$ integers match.
*#%*&=%%#5*&#G9=&;<*&=55=> epected3 actual3 elements@
0ass i8 the two arrays match.
&M#%%=2# can appen$e$ to any o8 the other
test assertions. 'hen there is on a$$itional arg5ment at the en$ o8 the arg5ment list which is a string to be printe$ i8 the test 8ails.
&M#%%=2#
6or the complete list o8 test assertions> see the ;nity $oc5mentation at: https://gith5b.com/'hrow'heSwitch/;nity.
1oc+ 2unction 2ormats 4riginal 2unction
C1oc+ 7enerated E,pect 2unction
void "uncvoid@
void "unc&#pectvoid@
void "uncparams@
void "unc&#pectepected¶ms@
retval "uncvoid@
void "unc&#pect=nd5eturnretval&to&return@
retval "uncparams@
void "unc&#pect=nd5eturnepected¶ms3 retval&to&return@
6or the complete list o8 available mock 85nctions> see the CMock $oc5mentation here: https://gith5b.com/'hrow'heSwitch/CMock/blob/master/$ocs/CMockKS5mmary.m$3generat e$-mock-mo$5le-s5mmary.
How to Use Ceedling for Embedded Test-Driven Development
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