tests: output to stderr to prevent interleaving with set -x output

tests/check-against-debootstrap-dist

@@ -83,11 +83,11 @@ rm /tmp/debian-{{ DIST }}-mm/var/lib/dpkg/arch
 # thus we first check for equality and then remove the files
 chroot /tmp/debian-{{ DIST }}-debootstrap dpkg --list > dpkg1
 chroot /tmp/debian-{{ DIST }}-mm dpkg --list > dpkg2
-diff -u dpkg1 dpkg2
+diff -u dpkg1 dpkg2 >&2
 rm dpkg1 dpkg2
 grep -v '^Priority: ' /tmp/debian-{{ DIST }}-debootstrap/var/lib/dpkg/status > status1
 grep -v '^Priority: ' /tmp/debian-{{ DIST }}-mm/var/lib/dpkg/status > status2
-diff -u status1 status2
+diff -u status1 status2 >&2
 rm status1 status2
 rm /tmp/debian-{{ DIST }}-debootstrap/var/lib/dpkg/status /tmp/debian-{{ DIST }}-mm/var/lib/dpkg/status
 # debootstrap exposes the hosts's kernel version
@@ -223,7 +223,7 @@ tar -C /tmp/debian-{{ DIST }}-debootstrap --numeric-owner --sort=name --clamp-mt
 tar -C /tmp/debian-{{ DIST }}-mm --numeric-owner --sort=name --clamp-mtime --mtime=$(date --utc --date=@{{ SOURCE_DATE_EPOCH }} --iso-8601=seconds) -cf /tmp/root2.tar .
 tar --full-time --verbose -tf /tmp/root1.tar > /tmp/root1.tar.list
 tar --full-time --verbose -tf /tmp/root2.tar > /tmp/root2.tar.list
-diff -u /tmp/root1.tar.list /tmp/root2.tar.list
+diff -u /tmp/root1.tar.list /tmp/root2.tar.list >&2
 rm /tmp/root1.tar /tmp/root2.tar /tmp/root1.tar.list /tmp/root2.tar.list
 
 # check if file properties (permissions, ownership, symlink names, modification time) differ

tests/create-arm64-tarball

@@ -39,5 +39,5 @@ $prefix {{ CMD }} --mode={{ MODE }} --variant=apt --architectures=arm64 {{ DIST
 	| grep -v '^\./usr/share/doc/[^/]\+/changelog\(\.Debian\)\?\.amd64\.gz$' \
 	| grep -v '^\./usr/share/man/man8/i386\.8\.gz$' \
 	| grep -v '^\./usr/share/man/man8/x86_64\.8\.gz$';
-} | sort | diff -u - tar2.txt
+} | sort | diff -u - tar2.txt >&2
 rm /tmp/debian-chroot.tar

tests/i386-which-can-be-executed-without-qemu

@@ -34,5 +34,5 @@ apt-get remove --yes qemu-user-static binfmt-support qemu-user
 	| grep -v '^\./usr/share/doc/[^/]\+/changelog\(\.Debian\)\?\.amd64\.gz$' \
 	| grep -v '^\./usr/share/man/man8/i386\.8\.gz$' \
 	| grep -v '^\./usr/share/man/man8/x86_64\.8\.gz$';
-} | sort | diff -u - tar2.txt
+} | sort | diff -u - tar2.txt >&2
 rm /tmp/debian-chroot.tar

tests/tarfilter-idshift

@@ -20,7 +20,7 @@ runuser -u user -- {{ CMD }} --mode=unshare --variant=apt --include=iputils-ping
 mkdir /tmp/debian-chroot
 tar --xattrs --xattrs-include='*' --directory /tmp/debian-chroot -xf /tmp/debian-chroot.tar ./bin/ping
 echo "/tmp/debian-chroot/bin/ping cap_net_raw=ep" > /tmp/expected
-getcap /tmp/debian-chroot/bin/ping | diff -u /tmp/expected -
+getcap /tmp/debian-chroot/bin/ping | diff -u /tmp/expected - >&2
 rm /tmp/debian-chroot/bin/ping
 rmdir /tmp/debian-chroot/bin
 rmdir /tmp/debian-chroot
@@ -44,16 +44,16 @@ tar --numeric-owner -tvf /tmp/debian-chroot.tar \
 	> /tmp/debian-chroot.txt
 tar --numeric-owner -tvf /tmp/debian-chroot-shifted.tar \
 	| sed 's/ \+/ /g' \
-	| diff -u /tmp/debian-chroot.txt -
+	| diff -u /tmp/debian-chroot.txt - >&2
 mkdir /tmp/debian-chroot
 tar --xattrs --xattrs-include='*' --directory /tmp/debian-chroot -xf /tmp/debian-chroot-shifted.tar
 echo "100000 100000" > /tmp/expected
-stat --format="%u %g" /tmp/debian-chroot/bin/ping | diff -u /tmp/expected -
+stat --format="%u %g" /tmp/debian-chroot/bin/ping | diff -u /tmp/expected - >&2
 echo "/tmp/debian-chroot/bin/ping cap_net_raw=ep" > /tmp/expected
-getcap /tmp/debian-chroot/bin/ping | diff -u /tmp/expected -
+getcap /tmp/debian-chroot/bin/ping | diff -u /tmp/expected - >&2
 echo "0 0" > /tmp/expected
 runuser -u user -- {{ CMD }} --unshare-helper /usr/sbin/chroot /tmp/debian-chroot stat --format="%u %g" /bin/ping \
-	| diff -u /tmp/expected -
+	| diff -u /tmp/expected - >&2
 echo "/bin/ping cap_net_raw=ep" > /tmp/expected
 runuser -u user -- {{ CMD }} --unshare-helper /usr/sbin/chroot /tmp/debian-chroot getcap /bin/ping \
-	| diff -u /tmp/expected -
+	| diff -u /tmp/expected - >&2