Hmm...how did this test pass without a `.netrc` file? You prob. need to create a fake `.netrc` file in test and pass the path to `NetrcAuth`:

```go
type NetrcAuth struct {
  netrcPath string
}

func (n NetrcAuth) String() string {
 if netrcPath == "" {
    netrcPath := filepath.Join(os.Getenv("HOME"), ".netrc")
 }
 
 ...
}

func TestNetrcAuth(t *testing.T) {
  netrcAuth := NetrcAuth{fakePath}
  ...
}
```