launch.json

{
  "version": "0.2.0",
  "configurations": [
    {
      "cwd": "${workspaceRoot}",
      "name": "Minitest - Run at cursor position",
      "type": "Ruby",
      "request": "launch",
      "program": "${workspaceRoot}/bin/rails",
      "args": [
        "test",
        "${file}:${lineNumber}"
      ]
    }, 
  ]
}