BigTable: try resetting BIGTABLE_EMULATOR_HOST to fix bigtable test errors

[igorbernstein2]

No description provided.

[igorbernstein2]

I couldn't reproduce the test failures locally, so I'm not sure if this is the actual cause of the issues.

[dhermes]

@igorbernstein2 Instead, can you use

@mock.patch('os.environ', new={})
def test_retry(self):
    ...

This way, any changes you make to os.environ in this method will be isolated.

Also, as far as reproducing, you can use the same Docker image our tests run in:

docker run \
  --rm \
  --tty \
  --interactive \
  --volume $(git rev-parse --show-toplevel):/var/code/gcp/ \
  googleapis/nox:0.17.0 \
  /bin/bash

(This won't help you decode the credentials file, but I'm happy to chat about how you might get one of those if you're not familiar.)

[dhermes]

@igorbernstein2 Since #3811 will be (temporarily) reverted, I have changed the base of this PR from master to pr-3811 (a branch in the main remote that has the changes from #3811 still)

[theacodes]

I'm closing this for now. It's been open since last year and no movement, and as far as I know our bigtable tests are passing.

Feel free to comment if this is still relevant.