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Troubleshooting

Issues with setting up or using the adapter

  • Run :checkhealth neotest-golang to review common issues.
  • Search previous discussions and issues.
  • Enable logging with the log_level option to further inspect what's going on under the hood.

If the problem persists and is configuration-related, please open a discussion here.

For bugs and feature requests, feel free to use discussions or file a detailed issue.

Common problems

  • Some terminals/environments will write inject linebreaks and even truncate output from go test as it is written to stdout. When this happens, it is impossible to reliably parse the output as JSON. This is a widespread problem and to mitigate it, use the gotestsum runner instead. Gotestsum writes all JSON test output to file, which is a lot more reliable. This particular problem has been reported to happen in some specific cases:

  • If you see non-UTF8 characters written to test output, you may want to enable the sanitize_output option.

  • You are using the default go_test_args (or use the -race flag), which requires CGO but you don't have gcc installed. Read more about this in the go_test_args option description.
  • You are passing invalid args to go_test_args, e.g., '-vet="all"' instead of '-vet=all'. (Quotes are valid in a shell, not go test itself)
  • Go did not compile and Neotest-golang failed to pick up on it. The intent is that neotest-golang should show a compilation error (please file a bug report if this happens).

Neotest is slowing down Neovim

Neotest, out of the box with default settings, can appear very slow in large projects (here, I'm referring to this kind of large). There are a few things you can do to speed up the Neotest appearance and experience in such cases, by tweaking the Neotest settings.

You can for example limit the AST-parsing (to detect tests) to the currently opened file, which in my opinion makes Neotest a joy to work with, even in ginormous projects. Second, you can tweak the concurrency settings, again for AST-parsing but also for concurrent test execution. Here is a simplistic example for lazy.nvim to show what I mean:

Lua
return {
  {
    "nvim-neotest/neotest",
    opts = {
      -- See all config options with :h neotest.Config
      discovery = {
        -- Drastically improve performance in ginormous projects by
        -- only AST-parsing the currently opened buffer.
        enabled = false,
        -- Number of workers to parse files concurrently.
        -- A value of 0 automatically assigns number based on CPU.
        -- Set to 1 if experiencing lag.
        concurrent = 1,
      },
      running = {
        -- Run tests concurrently when an adapter provides multiple commands to run.
        concurrent = true,
      },
      summary = {
        -- Enable/disable animation of icons.
        animated = false,
      },
    },
  },
}

See :h neotest.Config for more information.

Here is my personal Neotest configuration, for inspiration. Please note that I am configuring Go and the neotest-golang adapter in a separate file here.

Go test execution and parallelism

You can set the optional go_test_args to control the number of test binaries and number of tests to run in parallel using the -p and -parallel flags, respectively. Execute go help test, go help testflag, go help build for more information on this. There's also an excellent article written by @roblaszczak posted here that touches on this subject further.

"Error on launch: Failed to launch"

If you encounter "Error on launch: Failed to launch" in messages/notifications in nvim when you attempt to execute your tests, open up the dap-ui with :%lua require("dapui").open(). This should show any underlying errors encountered when nvim-dap tries to build/execute/attach the debugger and should guide you on how to troubleshoot.