test-suite fails in Slackware when compiling version 1.15

[André Simões]

Hi Selinger.

I'm receiving FAIL: 2 at make check at Slackware current with gcc 7.x...

Have you ever passed by something similar ? Any suggestions to correct the problem ?

Full log goes bellow:

========================================
   potrace 1.15: check/test-suite.log
========================================

# TOTAL: 8
# PASS:  6
# SKIP:  0
# XFAIL: 0
# FAIL:  2
# XPASS: 0
# ERROR: 0

.. contents:: :depth: 2

FAIL: postscript-check.sh
=========================

Checking PostScript output...
data1.pbm:            |========================================| 100% 
Difference: 1092
postscript-check.sh: test failed
Failed command: 73: ./pgmdiff /tmp/postscript-check.sh-2.YkzNGz ./data/data1.pbm.gs
FAIL postscript-check.sh (exit status: 1)

FAIL: pdf-check.sh
==================

Checking PDF output...
data1.pbm:            |========================================| 100% 
Difference: 1073
pdf-check.sh: test failed
Failed command: 75: ./pgmdiff /tmp/pdf-check.sh-2.Bbna2D ./data/data1.pbm.gs
FAIL pdf-check.sh (exit status: 1)

[Peter Selinger]

Thanks for reporting. This is nothing to worry about. The tests check the accuracy of a PostScript of PDF image by comparing the output of Ghostscript to a reference image. Since the output of Ghostscript is not 100% reproducible, the tests have a certain amount of tolerance built in; in the case of the two failures, the tolerances were not quite enough. The attached patch fixes the issue, but you can also just safely ignore the failed tests.