Function NewIsolatedTestConfig

internal/config/test.go:129–167

NewIsolatedTestConfig returns the real config implementation, built from cfgString and isolated from the machine running the tests. Pass "" for a config with no content. It also returns a function that reads back anything written to disk. Use it when the code under test exercises real config behavi

(t *testing.T, cfgString string)

// Callers that want one of the auth env vars set should set it after calling this,
// otherwise the value is cleared along with the ambient environment.
func NewIsolatedTestConfig(t *testing.T, cfgString string) (*cfg, func(io.Writer, io.Writer)) {
	keyring.MockInit()

	// go-gh reads these ahead of any stored config, so isolating the config file is
	// not enough on its own. A developer with GH_TOKEN exported, or any CI image that
	// provides one, would otherwise see an authenticated config here and fail tests
	// that assert on the logged out state.
	for _, key := range []string{
		"GH_TOKEN",
		"GITHUB_TOKEN",
		"GH_ENTERPRISE_TOKEN",
		"GITHUB_ENTERPRISE_TOKEN",
		"GH_HOST",
	} {
		t.Setenv(key, "")
	}

	c := ghConfig.ReadFromString(cfgString)
	cfg := cfg{c}

	// The real implementation of config.Read uses a sync.Once
	// to read config files and initialise package level variables
	// that are used from then on.
	//
	// This means that tests can't be isolated from each other, so
	// we swap out the function here to return a new config each time.
	ghConfig.Read = func(_ *ghConfig.Config) (*ghConfig.Config, error) {
		return c, nil
	}

	// The config.Write method isn't defined in the same way as Read to allow
	// the function to be swapped out and it does try to write to disk.
	//
	// We should consider whether it makes sense to change that but in the meantime
	// we can use GH_CONFIG_DIR env var to ensure the tests remain isolated.
	readConfigs := StubWriteConfig(t)

	return &cfg, readConfigs
}

// StubWriteConfig stubs out the filesystem where config file are written.
// It then returns a function that will read in the config files into io.Writers.