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Question Milena Donato · Dec 27, 2017

Unit test - how do you check if a variable is undefined or null?

#Caché #Beginner #Testing

Hi everyone

I'm new in Cache development language and I'm starting setting up Unit Tests.

How do you check with an Assert whether a certain variable is null or undefined?

The following assert throws an error on the "null": do $$$AssertEquals(myObj, null, "myObj is null")

Thanks a lot for your help and best regards

Milena

Discussion (5)0
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Comments

Robert Cemper · Dec 27, 2017

Try ""   instead of null which would be a variable named null

    do $$$AssertEquals(myObj, "", "myObj is null")

or

    set null="" do $$$AssertEquals(myObj, null, "myObj is null")

or to cover undefined as well

     do $$$AssertEquals($GET(myObj), "", "myObj is null")

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Eduard Lebedyuk  Dec 28, 2017 to Robert Cemper

Also possible to use $$$NULL macro:

do $$$AssertEquals(myObj, $$$NULL, "myObj is null")
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Robert Cemper  Dec 28, 2017 to Eduard Lebedyuk

I like macros but I'm always careful concerning their public availability.
This has changed to often over recent releases.

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Vitaliy Serdtsev  Dec 29, 2017 to Robert Cemper

You are right, the macro $$$NULL present only in %sqlMigration.inc and this is not the file that developers often include to its project.
I prefer to use the macro $$$NULLOREF/$$$NULLOID from %occExtent.inc, which is available by default in the class that inherits from %Library.Base, and for routines is enough to include %systemInclude.inc.

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Vitaliy Serdtsev · Dec 29, 2017

Undefined variable and the variable contains "" (null) is two different situations, e.g. (see $DATA):

<FONT COLOR="#0000ff">kill </FONT><FONT COLOR="#800000">myObj
</FONT><FONT COLOR="#0000ff">write $data</FONT><FONT COLOR="#000000">(</FONT><FONT COLOR="#800000">myObj</FONT><FONT COLOR="#000000">),! </FONT><FONT COLOR="#008000">; -> 0
</FONT><FONT COLOR="#0000ff">set </FONT><FONT COLOR="#800000">myObj</FONT><FONT COLOR="#000000">=</FONT><FONT COLOR="#0000ff">$$$NULLOREF
write $data</FONT><FONT COLOR="#000000">(</FONT><FONT COLOR="#800000">myObj</FONT><FONT COLOR="#000000">),! </FONT><FONT COLOR="#008000">; -> 1</FONT>
In your case it would be better to use $IsObject:
<FONT COLOR="#0000ff">kill </FONT><FONT COLOR="#800000">myObj
</FONT><FONT COLOR="#0000ff">write $IsObject</FONT><FONT COLOR="#000000">(</FONT><FONT COLOR="#800000">myObj</FONT><FONT COLOR="#000000">),! </FONT><FONT COLOR="#008000">; -> 0
</FONT><FONT COLOR="#0000ff">set </FONT><FONT COLOR="#800000">d</FONT><FONT COLOR="#000000">=</FONT><FONT COLOR="#0000ff">$$$NULLOREF
write $IsObject</FONT><FONT COLOR="#000000">(</FONT><FONT COLOR="#800000">myObj</FONT><FONT COLOR="#000000">),! </FONT><FONT COLOR="#008000">; -> 0
</FONT><FONT COLOR="#0000ff">set </FONT><FONT COLOR="#800000">myObj</FONT><FONT COLOR="#000000">=</FONT><FONT COLOR="#ff00ff">{}
</FONT><FONT COLOR="#0000ff">write $IsObject</FONT><FONT COLOR="#000000">(</FONT><FONT COLOR="#800000">myObj</FONT><FONT COLOR="#000000">),! </FONT><FONT COLOR="#008000">; -> 1</FONT>
Accordingly, should be <FONT COLOR="#0000ff">do $$$AssertTrue</FONT><FONT COLOR="#000000">('</FONT><FONT COLOR="#0000ff">$IsObject</FONT><FONT COLOR="#000000">(</FONT><FONT COLOR="#800000">myObj</FONT><FONT COLOR="#000000">), </FONT><FONT COLOR="#008000">"myObj is null"</FONT><FONT COLOR="#000000">)</FONT>
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