package afero import "testing" func TestCopyOnWrite(t *testing.T) { var fs Fs var err error base := NewOsFs() roBase := NewReadOnlyFs(base) ufs := NewCopyOnWriteFs(roBase, NewMemMapFs()) fs = ufs err = fs.MkdirAll("nonexistent/directory/", 0744) if err != nil { t.Error(err) return } _, err = fs.Create("nonexistent/directory/newfile") if err != nil { t.Error(err) return } }