Add test for `segments.py`

Tests/tests.json

@@ -2,5 +2,10 @@
     {
         "title": "Spher_polyline_area",
         "command": "$build_dir/Tests/test_spher_polyline_area"
+    },
+    {
+	"title": "Segments",
+	"command":
+	["$src_dir/segments.py", "$tests_old_dir/EGr2nd15md4/edgelist.csv"]
     }
 ]