How to test Go programs with relative directories?

From the testing docs:

"The package is built in a temporary directory so it does not interfere with the non-test installation."

So any code working with directories relative to the executable will not be present relative to Temp\go-build......

In other words, given the following:

.\helloplanet.go

.\planets\planetary.res

.\helloplanet_test.go

go test

Produces an exe in Temp\go-build... but it doesn't also re-create a planets\ subdir there, so any code in helloplanet.exe looking for planets\planetary.res of course won't find it.

How should one deal with this?

Here's a solution that actually works. I found this buried in the jetbrains forum. Here's the answer that user Daniil Maslov came up with :

The trick is actually very simple and is to get the current executing and add .. to the project root.

Create a new directory and file like testing_init.go with the following content:

package testing_init

import (
  "os"
  "path"
  "runtime"
)

func init() {
  _, filename, _, _ := runtime.Caller(0)
  dir := path.Join(path.Dir(filename), "..")
  err := os.Chdir(dir)
  if err != nil {
    panic(err)
  }
}

After that, just import the package into any of the test files:

package main_test

import (
  _ "project/testing_init"
)

Now you can specify paths from the project root

Though the test files are built in a temporary location, your working directory will be where you expect it. If you execute an os.Getwd() from within a test function, you'll see that your working directory is the package directory. This should work the same when running go test from within your package, or calling it with the full import path, as long as your package's location is in GOPATH.

In my packages, I often have a testadata directory, which is accessed via it's relative path, and have had no issues.