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Thursday, 1 December 2011

NOTE: Testing (Presenting the Results)

The preceding two articles in this series on testing presented a simple, generic macro for testing and recording test results. All that remains now is for us to tidy-up some loose ends.

Firstly, the macro assumes data set work.results already exists. And it also assumes that the data set contains appropriate variables named Tag and Result. We can quickly arrange that by being sure to include a call to the following macro in our testing code:

%macro assert_init(resultdata=work.results);
  data &resultdata;
    length Tag $32 Result $4;
    stop;
  run; 
%mend assert_init;

Finally, we want to present our results. We can do this easily with a simple call to PROC REPORT:

%macro assert_term(resultdata=work.results);
  title "Test Results";
  proc report data=&resultdata;
    columns tag result;
    define tag / order; 
  run; 
%mend assert_term;

Equipped thus, we can focus on our testing code, not the mechanics of collating and presenting results. For example, let's imagine we have some new code to test; the purpose of the code is to read a raw file (a.txt), create some computed columns, and write-out a SAS data set (perm.a). One of our tests is to check that the number of rows in the raw file matches the number of rows in the SAS data set. Here's our code to test this functionality:

%assert_init;
%include "code_to_be_tested.sas";
%assert_EqualRowCount(infile=a.txt,outdata=perm.a,tag=T01-1);
%assert_term;


We can make the results a tad more visual by colourising the pass/fail values:

%macro assert_term(resultdata=work.results);
  proc format;
    value $bkres 'PASS'='Lime'
                 'FAIL'='Red';
  run;

  title "Test Results";
  proc report data=&resultdata;
    columns tag result;
    define tag / order;
  define result / style(column)={background=$bkres.};
  run;
%mend assert_term;


This assumes you're using SAS Enterprise Guide. If not, you'll need to add some appropriate ODS statements around the PROC REPORT.

The downside of the macros as they stand at this point is that the results data set gets recreated every time we run the code. Maybe we don't want that because we want to collate test results from a number of separate bits of test code. So, finally, we can make the creation of the results data set conditional, i.e. if it doesn't exist we'll create, if it already exists then we'll leave it alone:

%macro assert_init(resultdata=work.results);
  %if not %sysfunc(exist(&resultdata)) %then
  %do;
    data &resultdata;
      length Tag $32 Result $4;
      stop;
    run;
  %end;
%mend assert_init;