test: add unit tests for graph (#296)

* test: added unit test of builder

* test: Add unit tests for nodes.py

* test: add more unit tests in test_nodes

* test: try to fix the unit test error on GitHub

* test: reformate the code of test_nodes.py

* Fix the test error of reset the local argument

* Fixed the test error by setup args

* reformat the code

src/graph/nodes.py

@@ -190,7 +190,7 @@ def human_feedback_node(
             goto = "reporter"
     except json.JSONDecodeError:
         logger.warning("Planner response is not a valid JSON")
-        if plan_iterations > 0:
+        if plan_iterations > 1:  # the plan_iterations is increased before this check
             return Command(goto="reporter")
         else:
             return Command(goto="__end__")