[FEATURE] Allow env to be passed to lib.process.run

[bendavis78]

My test environment requires certain env vars to be set that are different from my neovim env. While the pytest runner allows me to pass --envfile to pytest, it is doesn't load the vars early enough (I need the env to be loaded in prior to loading project modules, not just the tests), so I need another way to set the env for the test process.

nvim.loop.spawn takes an env argument that allows you to pass environment variables. It would be helpful if env could be passed in via a configuration var at at this point.

For example:

  local opts = {
    adapters = {
      require("neotest-python")({
        dap = { justMyCode = false },
        env = { VAR1 = "foo", VAR2 = "bar"}
      }),
    },
  }
  
  require("neotest").setup(opts)

[bendavis78]

Just realized this an issue w/ neotest-python, which should allow passing env into the adapter spec.

[erichaus]

this would be nice as I wouldn't have to rely on using pytest-env