wip support for running action_chain_runner tests via pants+pytest

contrib/runners/action_chain_runner/tests/unit/BUILD

@@ -5,4 +5,15 @@ __defaults__(
 
 python_tests(
     name="tests",
+    stevedore_namespaces=[
+        "st2common.rbac.backend",
+        "st2common.metrics.driver",
+        # TODO: we only need THIS runner, but this pulls in all.
+        "st2common.runners.runner",
+    ],
+    uses=["mongo"],
+    # TODO: need st2common.runners.runner stevedore namespace, but only this runner!
+    #dependencies=[
+    #    "contrib/runners/action_chain_runner",
+    #],
 )