tests: Pull things via http instead of local pulls

This causes us to use the same codepaths as in real use.
Also, there seems to be an issue with partial pulls for local remotes.

tests/libtest.sh

@@ -167,7 +167,9 @@ export FL_GPGARGS="--gpg-homedir=${FL_GPG_HOMEDIR} --gpg-sign=${FL_GPG_ID}"
 setup_repo () {
     GPGARGS="$FL_GPGARGS" . $(dirname $0)/make-test-runtime.sh org.test.Platform bash ls cat echo readlink > /dev/null
     GPGARGS="$FL_GPGARGS" . $(dirname $0)/make-test-app.sh > /dev/null
-    flatpak remote-add ${U} --gpg-import=${FL_GPG_HOMEDIR}/pubring.gpg test-repo repo
+    ostree trivial-httpd --autoexit --daemonize -p httpd-port .
+    port=$(cat httpd-port)
+    flatpak remote-add ${U} --gpg-import=${FL_GPG_HOMEDIR}/pubring.gpg test-repo "http://127.0.0.1:${port}/repo"
 }
 
 make_updated_app () {