Re: [PATCH] {master} tests: better way to compare lists in Makefile rules

[Stefano Lattarini]

On 02/06/2012 07:29 PM, Stefano Lattarini wrote:
> With this commit, we introduce a new helper shell script for use
> in the testsuite, which is meant to allow the test cases to easily
> check whether two whitespace-separated lists are equal; this ability
> is particularly useful to check for equality of the contents of make
> variables that are expected to contain multiple whitespace-separated
> words, and are defined through line continuations (or are rewritten
> by automake in this way), or contain expansion of potentially empty
> variables.
> 
> Before this change, a test checking that an usage like this one:
> 
>   VAR = valA
>   if COND1
>     VAR += val1 # com1
>   endif COND1
>   VAR += valC
> 
> worked as expected, couldn't use rules like:
> 
>   ## Don't work because $(VAR) expands to multiple words
>   verify:
>       test $(VAR) = "valA val1 valC"
> 
> nor like:
> 
>   ## Don't work because the final expansion of $(VAR) contains
>   ## repeated contiguous whitespace characters (it actually
>   ## equals "valA val1  valC", not "valA val1 valC"), and this
>   ## is an internal details which might change and which we
>   ## don't want to explicitly rely on.
>   verify:
>       test "$(VAR)" = "valA val1 valC"
> 
> Instead, we had to rely on cumbersome workaround such as:
> 
>   # Works, but is ugly.
>   verify:
>       test "`echo $(VAR)`" = "valA val1 valC"
> 
> or:
> 
>   # Works, but is even uglier.
>   verify:
>       echo BEG: $(VAR) :END | grep "BEG: valA val1 valC :END"
> 
> Now, with the help of the new 'is' script, we can perform such a
> check in a clearer and more straightforward way, as in:
> 
>   ## Works, and reads clearly.
>   verify:
>       is $(VAR) == valA val1 valC
> 
I've pushed this patch now.

Regards,
  Stefano