test_exp_cdc.sh: check returned gadgets

experiments/test_exp_cdc.sh

@@ -41,7 +41,7 @@ if True:
 
   import json
   from graph_tools.misc import graph_to_gadget
-  from graph_tools.parameters import CircuitDoubleCover
+  from graph_tools.parameters import CircuitDoubleCover, UnderlayingGraph
   from sage.all import Graph
   from parmap import parmap
 
@@ -50,6 +50,7 @@ if True:
     gadget = graph_to_gadget(G)
     real = gadget.eval(CircuitDoubleCover)
     exp = 2**(G.num_verts() // 2) // 2
+    assert G.is_isomorphic(gadget.eval(UnderlayingGraph))
   
     j = {
       "cdc_count": real,