Add test `Extract_component_nx`

Overlap/Tests/short_tests.json

@@ -650,5 +650,11 @@
 	    "$src_dir/Overlap/edgelist_to_Graphviz.py",
 	    "$tests_old_dir/EGr2nd15md4np3_cyclo/edgelist.csv", "eddy_graph.gv"
 	]
+    },
+    "Extract_component_nx":
+    {
+	"command":
+	["$src_dir/Overlap/extract_component_nx.py",
+	 "$tests_old_dir/EGr2nd15md4np3_cyclo/edgelist.csv", "286461"]
     }
 }