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

Question

Question

Milena Donato · Dec 27, 2017

#Beginner #Caché #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

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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")

1 0

Vitaliy Serdtsev · Dec 29, 2017

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

kill myObj
write $data(myObj),! ; -> 0
set myObj=$$$NULLOREF
write $data(myObj),! ; -> 1

In your case it would be better to use $IsObject:

kill myObj
write $IsObject(myObj),! ; -> 0
set d=$$$NULLOREF
write $IsObject(myObj),! ; -> 0
set myObj={}
write $IsObject(myObj),! ; -> 1

Accordingly, should be do $$$AssertTrue('$IsObject(myObj), "myObj is null")

0 0

score 0 · Answer 1 · 2017-12-28T08:13:04-05:00

Eduard Lebedyuk · Dec 28, 2017

Also possible to use $$$NULL macro:

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

0 0

score 0 · Answer 2 · 2017-12-28T08:54:53-05:00

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

score 1 · Answer 3 · 2017-12-29T01:31:11-05:00

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.