Do roundtrip from PPM instead of PBM

git-svn-id: https://svn.code.sf.net/p/netpbm/code/trunk@3888 9d0c8265-081b-0410-96cb-a4ca84ce46f8

Author: giraffedata

test/pj-roundtrip.ok

@@ -1,4 +1,4 @@
 Test 1. Should print:  0 0 0 0 : 0
 0 0 0 0 : 0
-Test 2. Should print:  0 0 0 0 0 : 0
-0 0 0 0 0 : 0
+Test 2. Should print:  0 0 : 0
+0 0 : 0

test/pj-roundtrip.test

@@ -1,6 +1,6 @@
 #! /bin/bash
 # This script tests: ppmtopj pjtoppm
-# Also requires: pamseq pnmremap pamtopnm pamdepth ppmtopgm pgmtopbm
+# Also requires: pamseq pnmremap pamtopnm pamdepth ppmtoppm
 
 echo "Test 1. Should print:  0 0 0 0 : 0"
 
@@ -15,8 +15,12 @@ ppmtopj ${test8_ppm} | pjtoppm | pamdepth 1 | \
 
 rm ${test8_ppm}
 
-echo "Test 2. Should print:  0 0 0 0 0 : 0"
+echo "Test 2. Should print:  0 0 : 0"
 
-ppmtopj testgrid.pbm | pjtoppm | ppmtopgm | pgmtopbm | \
-  cmp -s - testgrid.pbm > /dev/null
+testout_ppm=${tmpdir}/testout.ppm
+
+ppmtopj testgrid.pbm | pjtoppm > ${testout_ppm}
+  ppmtoppm < testgrid.pbm | cmp -s - ${testout_ppm} > /dev/null
   echo ${PIPESTATUS[@]} ":" $?
+
+rm ${testout_ppm}