Phoenix tries to render errors when testing (failed) GraphQL mutation

When testing GraphQL mutation, and if the mutation returns %{error: "error message"}, we should expect json_response(conn, 200) to return the following json data:

{
  "data": {
     "someMutation": null
  },
  "errors": [
    {
      "locations": [
        {
          "column": 3,
          "line": 2
        }
      ],
      "message": "error message",
      "path": [
        "someMutation"
      ]
    }
  ]
}

But this is not the case with {:phoenix, "~> 1.6.9"}, {:absinthe, "~> 1.6.0"}, and {:absinthe_plug, "~> 1.5"}. Phoenix tries to render the error view instead of returning the above-mentioned json data, even if, I set render_errors to false in the endpoint config.

Does anyone have any idea how to resolve this issue?

Sorry! I was my mistake.