Merge "use master upper-constraints when building tempest venv"

Author: Zuul

lib/tempest

@@ -554,7 +554,10 @@ function configure_tempest {
     if [[ "$OFFLINE" != "True" ]]; then
         tox -revenv-tempest --notest
     fi
-    tox -evenv-tempest -- pip install -c $REQUIREMENTS_DIR/upper-constraints.txt -r requirements.txt
+
+    # The requirements might be on a different branch, while tempest needs master requirements.
+    git -C $REQUIREMENTS_DIR show master:upper-constraints.txt > u-c-m.txt
+    tox -evenv-tempest -- pip install -c u-c-m.txt -r requirements.txt
 
     # Auth:
     iniset $TEMPEST_CONFIG auth tempest_roles "Member"