Add test for option `-n` of `report_graph.py`

Overlap/Tests/short_tests.json

@@ -602,5 +602,14 @@
 	    "$tests_old_dir/Greece/SHPC"
 	],
         "input": "&MAIN_NML max_delta = 4, cyclone = f/\n"
+    },
+    {
+	"title": "Report_graph_node",
+	"description": "Test option --node of report_graph.py.",
+	"command":
+	[
+	    "$src_dir/Overlap/report_graph.py", "--gv", "--merging",
+	    "--node=429691", "$tests_old_dir/EGr2nd15md4np3_cyclo/edgelist.csv"
+	]
     }
 ]