diff --git a/tests/pngtest-all b/tests/pngtest-all
index 5e96451d3..ba621f376 100755
--- a/tests/pngtest-all
+++ b/tests/pngtest-all
@@ -1,16 +1,84 @@
 #!/bin/sh
 
-# normal execution
+st=0    # exit status (set to 1 if a test fails)
+fail="**FAIL**"
+success=" SUCCESS"
+TEST(){
+   # Try to make the log file easier to read:
+   test_status="$success"
+   echo "=============== PNGTEST $* ===================="
+   ./pngtest "$@" || {
+      st=$?
+      test_status="$fail"
+   }
+   echo "===============$test_status $* ===================="
+}
 
-./pngtest --strict ${srcdir}/pngtest.png
+# The "standard" test
+TEST --strict "${srcdir}"/pngtest.png
 
-# various crashers
-# using --relaxed because some come from fuzzers that don't maintain CRC's
+# Various crashers
+# Use --relaxed because some come from fuzzers that don't maintain CRCs
+TEST --relaxed "${srcdir}"/contrib/testpngs/crashers/badcrc.png
+TEST --relaxed "${srcdir}"/contrib/testpngs/crashers/badadler.png
+TEST --xfail "${srcdir}"/contrib/testpngs/crashers/bad_iCCP.png
+TEST --xfail "${srcdir}"/contrib/testpngs/crashers/empty_ancillary_chunks.png
+for file in "${srcdir}"/contrib/testpngs/crashers/huge_*_chunk.png
+do
+   TEST --xfail "$file"
+done
+for file in "${srcdir}"/contrib/testpngs/crashers/huge_*safe_to_copy.png
+do
+   TEST --xfail "$file"
+done
+TEST --xfail "${srcdir}"/contrib/testpngs/crashers/huge_IDAT.png
 
-./pngtest --relaxed ${srcdir}/contrib/testpngs/crashers/badcrc.png
-./pngtest --relaxed ${srcdir}/contrib/testpngs/crashers/badadler.png
-./pngtest --xfail ${srcdir}/contrib/testpngs/crashers/bad_iCCP.png
-./pngtest --xfail ${srcdir}/contrib/testpngs/crashers/empty_ancillary_chunks.png
-./pngtest --xfail ${srcdir}/contrib/testpngs/crashers/huge_*_chunk.png \
-    ${srcdir}/contrib/testpngs/crashers/huge_*safe_to_copy.png
-./pngtest --xfail ${srcdir}/contrib/testpngs/crashers/huge_IDAT.png
+# Regression tests for required warnings (or errors):
+check_stdout(){
+   # $1: the test file (a bad PNG which must produce a warning, etc)
+   # $2: a string which must occur at the end of line on stdout for success
+   # result: an error message on descriptor 3 if the string is NOT found
+   found=
+   while read line
+   do
+      case "$line" in
+         *"$2") found=1;;
+      esac
+      echo "$line" # preserve the original output verbatim
+   done
+   # output the missing warning on descriptor 3:
+   test -z "$found" && echo "$1: $2" >&3
+}
+# NOTE: traditionally the Bourne shell executed the last element in a pipe
+# sequence in the original shell so it could set variables in the original
+# shell however this is not reliable and doesn't work in bash.
+#
+# It *is* reliable to use the actual exit status of the last command in
+# the pipeline.
+exec 4>&1 # original stdout - the log file
+{
+   exec 3>&1 # stdout is the pipe at this point
+   fail=" FAIL(EXPECTED)" # runtime scope
+   success=" SUCCESS(UNEXPECTED)" # there should be a write error
+   for file in "${srcdir}"/contrib/testpngs/badpal/*.png
+   do
+     # The exit code is ignored here, the test is that the particular errors
+     # (warnings) are produced.  The original output still ends up in the log
+     # file.
+     TEST "$file" |
+        check_stdout "$file" 'IDAT: Read palette index exceeding num_palette' |
+        check_stdout "$file" 'Wrote palette index exceeding num_palette' >&4
+   done
+   exec 3>&-
+} | {
+   # This may not be a sub-shell, if it is 'st' is undefined and the exit
+   # just ends up as 'exit'.
+   while read error
+   do
+      echo "MISSING REPORT: $error"
+      st=1
+   done
+   exit $st
+} || st=$?
+
+exit $st