Raven in tests.

Package version (if known): > 2.0

## Describe the bug
There are still raven imports in tests:
```
@pytest.yield_fixture()
def sentry_emit():
"""Mock Sentry emit."""
from raven.handlers.logging import SentryHandler

with patch.object(SentryHandler, "emit") as sentry_emit:
yield sentry_emit
```

Search the test suite for the raven.handlers.logging.SentryHandler import shown in the issue and inspect the sentry_emit fixture. Determine the intended replacement or removal for this obsolete test dependency, then verify that the affected tests pass without Raven imports.

Written by the indexing model from the issue text.