ci: attempt to use --parallel flag in tox

scripts/ci/run

@@ -38,4 +38,4 @@ if ! command -v python3 &> /dev/null; then
 fi
 
 "$PY_BIN" -m pip install --user tox
-"$PY_BIN" -m tox
+"$PY_BIN" -m tox --parallel --parallel-live "$@"

tox.ini

@@ -15,10 +15,14 @@ passenv =
   PYTHONPYCACHEPREFIX
 
 
+# note: --use-pep517 below is necessary for tox --parallel flag to work properly
+# otherwise it seems that it tries to modify .eggs dir in parallel and it fails
+
+
 # just the very core tests with minimal dependencies
 [testenv:tests-core]
 commands =
-    pip install -e .[testing]
+    pip install --use-pep517 -e .[testing]
     
     # seems that denylist tests rely on it? ideally we should get rid of this in tests-core
     pip install orjson
@@ -47,7 +51,7 @@ commands =
 # TODO not sure if need it?
 setenv = MY_CONFIG = nonexistent
 commands =
-    pip install -e .[testing]
+    pip install --use-pep517 -e .[testing]
 
     # installed to test my.core.serialize while using simplejson and not orjson
     pip install simplejson
@@ -104,7 +108,7 @@ commands =
 [testenv:mypy-core]
 allowlist_externals = cat
 commands =
-    pip install -e .[testing,optional]
+    pip install --use-pep517 -e .[testing,optional]
     pip install orgparse # used it core.orgmode?
     pip install gpxpy # for hpi query --output gpx
 
@@ -121,7 +125,7 @@ commands =
 [testenv:mypy-misc]
 allowlist_externals = cat
 commands =
-    pip install -e .[testing,optional]
+    pip install --use-pep517 -e .[testing,optional]
 
     hpi module install --parallel                \
         my.arbtt                  \