id,node_id,number,title,user,state,locked,assignee,milestone,comments,created_at,updated_at,closed_at,author_association,active_lock_reason,draft,pull_request,body,reactions,performed_via_github_app,state_reason,repo,type
784484810,MDU6SXNzdWU3ODQ0ODQ4MTA=,4798,attributes that are lists of strings with a single member don't survive a round-trip,7226087,open,0,,,7,2021-01-12T18:34:26Z,2023-09-16T09:52:10Z,,NONE,,,,"**What happened**:

If I create a Dataset with an attr that is a list of strings with only a single member, write it to netcdf and open it again, the attr is a single string instead of a list of strings.

**What you expected to happen**:

Writing the Dataset to netcdf and opening it should not change the attrs.

**Minimal Complete Verifiable Example**:

```python
import xarray as xr

ds = xr.Dataset(attrs={""foo"": [""bar""]},)

ds.to_netcdf(""ds.nc"", engine=""netcdf4"")
rd = xr.open_dataset(""ds.nc"", engine=""netcdf4"")

assert ds.attrs[""foo""] == rd.attrs[""foo""]
```

**Anything else we need to know?**:

This was implemented in [PR2045](https://github.com/pydata/xarray/pull/2045), including the test [test_setncattr_string](https://github.com/pydata/xarray/blob/master/xarray/tests/test_backends.py#L1440). However, there `assert_array_equal` is used to compare the attrs after a roundtrip ([line 1454](https://github.com/pydata/xarray/blob/master/xarray/tests/test_backends.py#L1454) ), which unfortunately compares element-wise if one of the elements is a scalar. Changing the
test like this:
```diff
-                assert_array_equal(one_element_list_of_strings, totest.attrs[""bar""])
+                assert one_element_list_of_strings == totest.attrs[""bar""]
```
corrects it (the test then fails currently).


**Environment**:

<details><summary>Output of <tt>xr.show_versions()</tt></summary>



INSTALLED VERSIONS
------------------
commit: f52a95cbe694336fe47bc5a42c713bee8ad74d64
python: 3.8.6 (default, Sep 25 2020, 09:36:53) 
[GCC 10.2.0]
python-bits: 64
OS: Linux
OS-release: 5.8.0-36-generic
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8
LOCALE: en_US.UTF-8
libhdf5: 1.12.0
libnetcdf: 4.7.4

xarray: 0.16.3.dev75+gf52a95cb
pandas: 1.2.0
numpy: 1.19.5
scipy: None
netCDF4: 1.5.5.1
pydap: None
h5netcdf: None
h5py: None
Nio: None
zarr: None
cftime: 1.3.0
nc_time_axis: None
PseudoNetCDF: None
rasterio: None
cfgrib: None
iris: None
bottleneck: None
dask: 2020.12.0
distributed: 2020.12.0
matplotlib: None
cartopy: None
seaborn: None
numbagg: None
pint: None
setuptools: 51.1.2
pip: 20.3.3
conda: None
pytest: 6.2.1
IPython: None
sphinx: None



</details>
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