diff --git a/integration/upstream-tests/test.sh b/integration/upstream-tests/test.sh
index 21aa141..0db9468 100755
--- a/integration/upstream-tests/test.sh
+++ b/integration/upstream-tests/test.sh
@@ -3,6 +3,22 @@
 set -eux
 set -o pipefail
 
+# Prepare systemd source tree
+#
+# Note: the snippet below assumes that the target PR branch is always 'main'
+#
+# Relevant docs:
+#   - https://packit.dev/docs/configuration/upstream/tests#optional-parameters
+git clone "${PACKIT_TARGET_URL:-https://github.com/systemd/systemd}" systemd
+cd systemd
+# If we're running in a pull request job, merge the remote branch into the current main
+if [[ -n "${PACKIT_SOURCE_URL:-}" ]]; then
+    git remote add pr "${PACKIT_SOURCE_URL:?}"
+    git fetch pr "${PACKIT_SOURCE_BRANCH:?}"
+    git merge "pr/$PACKIT_SOURCE_BRANCH"
+fi
+git log -1
+
 export ARTIFACT_DIRECTORY="${TMT_TEST_DATA:?}"
 export TEST_SAVE_JOURNAL=fail
 export TEST_SHOW_JOURNAL=warning