test.json

{
  "nodes": [
    {"id": "n1", "group": 1},
    {"id": "n2", "group": 1},
    {"id": "n3", "group": 1},
    {"id": "n4", "group": 1},
    {"id": "n5", "group": 1},
    {"id": "n6", "group": 1},
    {"id": "n7", "group": 1}
  ],
  "links": [
    {"source": "n1", "target": "n2", "value": 1},
    {"source": "n1", "target": "n4", "value": 1},
    {"source": "n1", "target": "n6", "value": -1},

    {"source": "n2", "target": "n3", "value": 1},
    {"source": "n2", "target": "n5", "value": -1},
    {"source": "n2", "target": "n7", "value": -1},

    {"source": "n3", "target": "n1", "value": 1},
    {"source": "n3", "target": "n4", "value": 1},
    {"source": "n3", "target": "n5", "value": -1},

    {"source": "n4", "target": "n2", "value": 1},
    {"source": "n4", "target": "n3", "value": 1},
    {"source": "n4", "target": "n6", "value": -1},

    {"source": "n5", "target": "n1", "value": -1},
    {"source": "n5", "target": "n5", "value": 1},
    {"source": "n5", "target": "n6", "value": 1},
    
    {"source": "n6", "target": "n2", "value": -1},
    {"source": "n6", "target": "n6", "value": 1},
    {"source": "n6", "target": "n7", "value": 1},

    {"source": "n7", "target": "n1", "value": -1},
    {"source": "n7", "target": "n2", "value": -1},
    {"source": "n7", "target": "n4", "value": -1}
  ]
}