add a test for apt-key export{,all}

Git-Dch: Ignore

cmdline/apt-key.in

@@ -380,8 +380,8 @@ case "$command" in
 	foreach_keyring_do 'fingerprint_keys_from_keyring' "$@"
 	;;
     export|exportall)
-	foreach_keyring_do 'import_keys_from_keyring' "${GPGHOMEDIR}/trusted.gpg"
-	$GPG_CMD --keyring "${GPGHOMEDIR}/trusted.gpg" --armor --export "$@"
+	foreach_keyring_do 'import_keys_from_keyring' "${GPGHOMEDIR}/pubring.gpg"
+	$GPG_CMD --keyring "${GPGHOMEDIR}/pubring.gpg" --armor --export "$@"
 	;;
     adv*)
 	setup_merged_keyring

test/integration/test-apt-key

@@ -42,6 +42,13 @@ gpg:              unchanged: 1' aptkey --fakeroot update
 	testfileequal ./aptkey.list 'pub   2048R/27CE74F9 2013-07-12 [expired: 2013-07-13]
 pub   2048R/DBAC8DAE 2010-08-18'
 
+	msgtest 'Check that Sixpack key can be' 'exported'
+	aptkey export 'Sixpack' > aptkey.export
+	aptkey --keyring rootdir/etc/apt/trusted.gpg.d/joesixpack.gpg exportall > aptkey.exportall
+	testsuccess --nomsg cmp aptkey.export aptkey.exportall
+	testsuccess test -s aptkey.export
+	testsuccess test -s aptkey.exportall
+
 	msgtest 'Execute update again to trigger removal of' 'Rex Expired key'
 	testsuccess --nomsg aptkey --fakeroot update