Nice suggestion. How about assert_no_warnings? Not sure if supress_warnings is a bit over the top?

```python from contextlib import contextmanager import warnings

@contextmanager def assert_no_warnings():

with warnings.catch_warnings(record=True) as record:
    yield
    assert len(record) == 0, "got unexpected warning(s)"

@contextmanager def supress_warnings(*messages):

messages = ("",) if not messages else messages
with warnings.catch_warnings():
    for message in messages:
        warnings.filterwarnings("ignore", message)
    yield

```

```python with supress_warnings(): warnings.warn("test")

with supress_warnings("test"): warnings.warn("test")

with supress_warnings("not test", "something else"): warnings.warn("test")

with assert_no_warnings(): pass

with assert_no_warnings(): warnings.warn("test") ```

what do you think about adding no_warnings() and suppress_warnings() to xarray.tests.__init__? For those pytest recommends ```python

no_warnings

with warnings.catch_warnings(): warnings.simplefilter("error")

...

or, without the stacktrace

with warnings.catch_warnings(record=True) as record: ...

assert len(record) == 0

or, with pytest.warns()

with pytest.warns() as record: ...

assert len(record) == 0

suppress

with warnings.catch_warnings(): warnings.simplefilter("ignore")

...

```

but those can easily get a name and be a bit easier to read. E.g. for the version of no_warnings() used in this PR: python @contextmanager def no_warnings(): with warnings.catch_warnings(record=True) as record: yield assert len(record) == 0

Thanks @mathause ! LGTM

close/ reopen