func TestParallelFinalFuncReturnsError(t *testing.T) { var err errs.Err err = Parallel(f1, f2, func(res1, res2 string, err errs.Err) {}) assert(t, err == nil) err = Parallel(f1, fErr, func(res1, res2 string, err errs.Err) {}) assert(t, err != nil) err = Parallel(f1, f2, func(res1, res2 string, err errs.Err) errs.Err { return nil }) assert(t, err == nil) err = Parallel(f1, fErr, func(res1, res2 string, err errs.Err) errs.Err { return errors.New("A new errs.Err") }) assert(t, err != nil) assert(t, err.Error() == "A new errs.Err") err = Parallel(f1, f2, func(res1, res2 string, err errs.Err) errs.Err { return nil }) assert(t, err == nil) }