fix tests

Author: samuelgarcia

src/spikeinterface/comparison/basecomparison.py

@@ -137,7 +137,7 @@ def _do_graph(self):
         for comp_name, comp in self.comparisons.items():
             for u1 in comp.hungarian_match_12.index.values:
                 u2 = comp.hungarian_match_12[u1]
-                if u2 != -1:
+                if u2 != -1 and u2 != "":
                     name_1, name_2 = comp_name
                     node1 = name_1, u1
                     node2 = name_2, u2

src/spikeinterface/comparison/tests/test_templatecomparison.py

@@ -45,7 +45,7 @@ def test_compare_multiple_templates():
 
     for u1 in temp_cmp.hungarian_match_12.index.values:
         u2 = temp_cmp.hungarian_match_12[u1]
-        if u2 != -1:
+        if u2 != -1 and u2 != "":
             assert u1 == u2
 
     # multi-comparison