diff -Nur a/desktop/test-appdata.sh.in b/desktop/test-appdata.sh.in
--- a/desktop/test-appdata.sh.in	2019-04-07 14:38:14.000000000 +0300
+++ b/desktop/test-appdata.sh.in	2019-11-06 23:19:32.000000000 +0300
@@ -2,8 +2,8 @@
 
 # TODO: use validate-strict when the last errors for a strict validation
 # are fixed.
-appstream-util validate-relax ${GIMP_TESTING_ABS_TOP_BUILDDIR}/desktop/org.gimp.GIMP.appdata.xml && \
-appstream-util validate-relax ${GIMP_TESTING_ABS_TOP_BUILDDIR}/desktop/gimp-data-extras.metainfo.xml && \
+appstream-util validate-relax --nonet ${GIMP_TESTING_ABS_TOP_BUILDDIR}/desktop/org.gimp.GIMP.appdata.xml && \
+appstream-util validate-relax --nonet ${GIMP_TESTING_ABS_TOP_BUILDDIR}/desktop/gimp-data-extras.metainfo.xml && \
 if [ $(expr @GIMP_MICRO_VERSION@ % 2) = 0 ]; then
   grep TODO ${GIMP_TESTING_ABS_TOP_BUILDDIR}/desktop/org.gimp.GIMP.appdata.xml
   if [ $? = 0 ]; then