2.0", "method": "foobar, "params": "bar", "baz]
    `);
    // Send invalid request (method must be string)
    send(socket, `
        {"jsonrpc": "2.0", "method": 1, "params": "bar"}
    `);
    // Send malformed batch request (incomplete JSON)
    send(socket, `[
      {"jsonrpc": "2.0", "method": "sum", "params": [1,2,4], "id": "1"},
      {"jsonrpc": "2.0", "method"
    ]`);
    // Send empty batch request
    send(socket, `[]`);
    // Send invalid batch (contains non-object element)
    send(socket, `