PHP自带可以代替echo调试的unit函数

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今天发现个函数assert和assert_options,他们组合可以完成一个简单的PHP unit的功能,但是实在是太简单,所以用处不太大,但是还是记录一下好了.

主要问题是不能灵活的自己定义错误的提示信息,只能提示出问题的文件和行数.

具体的使用方法可以看<>或者<>

同时可以结合<>中"XXVII.ErrorHandlingandLoggingFunctions"章节里的东西,共同使用.

下面是我写的一个测试文件,包含了所有的功能的测试,不过ASSERT_QUIET_EVAL一直不太明白,没测试出来具体有什么样作用

<?PHP

functionassert_failed($file,$line,$expr){

print"Assertionfailedin$file[$line]:$expr<br/>";

}

//error_reporting设置为0,相当于调用assert_options(ASSERT_WARNING,0);

//error_reporting(0);

//是否启用对ASSERT_ACTIVE的支持

assert_options(ASSERT_ACTIVE,1);

//是否在发送第一次wanning的时候,停止脚本的执行

assert_options(ASSERT_BAIL,0);

//没搞定,还不明白具体怎么用,偶测试不出来

//assert_options(ASSERT_QUIET_EVAL,0);

echo"step1<br/>";

assert(1==1);

echo"step2<br/>";

assert(2==1);

echo"step3<br/>";

//设定assert的callback样式,可以自己定义wanning信息显示时的样式

assert_options(ASSERT_CALLBACK,'assert_failed');

//不显示assert()自己产生warnning信息，如果设置了ASSERT_CALLBACK，仍然还会显示ASSERT_CALLBACK函数对应的信息，但是函数中传入的$expr参数不起作用.

//assert_options(ASSERT_WARNING,1);

assert(1==1);

assert((1/0)>2);

echo"step4<br/>";

Theassert()functionisacleverone
thatworksalongthesamelinesasourprintstatements,butitonlyworksifacertainconditionisnotmatched.Essentially,assert()isusedtosay"Thisstatementmustbetrueifitisn't,pleasetellme."Forexample:

print"Stage1/n";

assert(1= =1);

print"Stage2/n";

assert(1= =2);

print"Stage3/n";

Herewehavetwoassert()s,withthefirstcallassertingthatonemustbeequaltoone,andthesecondcallassertingthatonemustbeequaltotwo.Asitisimpossibletoredefineconstantslike1and2,thefirstassert()willalwaysevaluatetotrue,andthesecondwillalwaysevaluatetofalse.Hereistheoutputfromthescript:

Stage1

Stage2

Warning:assert()[http://www.PHP.net/function.assert]:Assertionfailed

in/home/paul/sandbox/PHP/assert.PHPonline5

Stage3

Thefirstassert()isnotseenintheoutputatallbecauseitevaluatedtoTRue,whereasthesecondassert()evaluatedtofalse,sowegetawarningaboutanassertionfailure.However,scriptexecutioncarriesonsothatwesee"Stage3"aftertheassertionfailurewarning.Aslongasassertionsevaluatetotrue,theyhavenoeffectontherunningofthescript,whichmeansyoucaninsertthemfordebuggingpurposesandnothavetoworryabouttakingthemoutonceyouarefinisheddebugging.

Ifyouareworriedaboutyourassertionsslowingexecutiondown,which,althoughthespeedhitwillbeminimal,isstillavalidconcern,youcandisableexecutionofassert()byusingtheassert_options()functionorbysettingassert.activetoOffinyourPHP.inifile.Ifyouwanttouseassert_options(),ittakestwoparameters:theoptiontosetandthevalueyouwishtosetitto.

Table22-1showsthelistofoptionsyoucanuseforthefirstparameterofassert_options():

Table22-1.Firstparameterofassert_options()

Parameter Default Description

ASSERT_ACTIVE On Enablesevaluationofassert()calls

ASSERT_WARNING On MakesPHPoutputawarningforeachfailedassertion

ASSERT_BAIL Off ForcesPHPtoendscriptexecutiononafailedassertion

ASSERT_QUIET_EVAL Off Ignoreserrorsinassert()calls

ASSERT_CALLBACK Off Namesuserfunctiontocallonafailedassertion

Todisableassert()calls,usethislineofcode:

assert_options(ASSERT_ACTIVE,0);

AndtomakePHPendscriptexecutionratherthanjustissueawarning,wecanusethislineofcode:

assert_options(ASSERT_BAIL,1);

NotethatalloftheseoptionscanbesetinyourPHP.inifilesothattheyarealwaysineffect.Theoptionstochangethereareassert.active,assert.warning,assert.bail,assert.quiet_eval,andassert_callback.

ASSERT_CALLBACKisausefuloption,asitallowsyoutowriteanerrorhandlerforwhenyourcodefailsanassertion.Ittakesthestringnameofafunctiontoexecutewhenassertionsfail,andthefunctionyoudefinemusttakethreeparameters:onetoholdthefilewheretheassertionoccurred,onetoholdtheline,andonetoholdtheexpression.Usingallthreetogetherinyourcallbackfunctionallowsyoutogeneratemeaningfulerrormessagesthatyoucandebug.Forexample:

functionassert_failed($file,$line,$expr){

print"Assertionfailedin$fileonline$line:$expr/n";

}

assert_options(ASSERT_CALLBACK,'assert_failed');

assert_options(ASSERT_WARNING,0);

$foo=10;

$bar=11;

assert($foo>$bar);

Thatexampleshowsacallbackfunctiondefinedthattakes$file,$line,and$exprforthethreevariablespassedin,andoutputsthemwheneveranassertionfails.Tomakethatresultactuallyhappen,assert_options()iscalledtoletPHPknowthatassert_failed()isthecorrectfunctiontouseasacallbacknotethattherearenobracketsafterthestringbeingpassedintoassert_options().

ASSERT_WARNINGisalsodisabled,whichstopsPHPfromoutputtingawarningaswellasrunningthecallbackfunction.Finally,twovariablesareset,andareusedaspartofacalltoassert()asyoucansee,$fooisquiteclearlynotgreaterthan$bar,whichmeanstheassertionwillfailandcallourcallback.So,theoutputfromthescriptis:Assertionfailedin/home/paul/tmp/blerg.PHPonline9:$foo>$bar.

Youcanassert()anystatementyoulike,aslongasitwillreturneitherTRueorfalse.Thismakestheassert()functionincrediblypowerfulevenmoresowhenyouthinkthatyoucanjustturnoffassertionexecutiontomakethecoderunatfullspeed.

Herearesomemoreexamplesofassert()ablethings:

assert($savings>=$salary/10);

assert($myarray= =array("apone","burke","hicks"));

assert(preg_match("/wildsheepchase/",$book));