TST: Enable Google BigQuery (pandas.io.gbq) integration testing #11089
- [ x ] closes #11089
- [ x ] tests added / passed
- [ x ] passes `git diff upstream/master | flake8 --diff`

whoo hoo!

only thing, the attached encrypted json file is decrpyted by the obfuscated travis variables right? IOW it is ONLY usable on travis
 > only thing, the attached encrypted json file is decrpyted by the obfuscated travis variables right? IOW it is ONLY usable on travis

Correct! The json credentials file should only be decrypted on Travis.  The private key is tied to the repository and only available in the Travis environment. 
 @jreback I'm not sure if I have access to encrypt the file for the pydata/pandas repo (I used my forked repo). Are you able to run `travis encrypt-file travis_gbq.json` in the root directory of pydata/pandas ? 

You'll need to rename the credentials file (previously sent via email) as `travis_gbq.json` from the root directory of pydata/pandas, but make sure not to commit `travis_gbq.json`. Only commit the `travis_gbq.json.enc` file.

Also, please modify line 232 in `.travis.yml` with the correct name of the environment variables on travis which contain the private key, which are provided after running `travis encrypt-file ...`

Here is the error I get when I try to create `travis_gbq.json.enc`:

```
tony@tonypc:~/pandas-getencr$ travis encrypt-file travis_gbq.json
encrypting travis_gbq.json for pydata/pandas
storing result as travis_gbq.json.enc
storing secure env variables for decryption
resource not found ({"error":"Couldn't find repository"})
```

I didn't receive this error on my forked repo. It may work if you run it
 did a PR to your branch. I moved the files to ci/ but the keys should work. lmk if you need anything.
 I used the changes from https://github.com/parthea/pandas/pull/1 in this PR and I receive the following error:

```
> openssl aes-256-cbc -K $encrypted_1d9d7b1f171b_key -iv $encrypted_1d9d7b1f171b_iv -in ci/travis_gbq.json.enc -out ci/travis_gbq.json -d

iv undefined
```

I believe there is a security restriction on pull requests from forked repos as mentioned here:
https://docs.travis-ci.com/user/pull-requests#Pull-Requests-and-Security-Restrictions

```
The most important restriction for pull requests is about secure environment variables and encrypted data.

A pull request sent from a fork of the upstream repository could be manipulated to expose any environment variables. The upstream repository’s maintainer would have no protection against this attack, as pull requests can be sent by anyone with a fork.

Travis CI makes encrypted variables and data available only to pull requests coming from the same repository. These are considered trustworthy, as only members with write access to the repository can send them.

Pull requests sent from forked repositories do not have access to encrypted variables or data.
```

Can I show a successful pass on my forked repo with my own encrypted file ? 
I updated the credentials file so that the tests pass in my forked repo. Here is a link to the test in progress: https://travis-ci.org/parthea/pandas/builds/155756133
 Are these errors expected?

```
======================================================================
ERROR: pandas.io.tests.test_pickle.TestPickle.test_pickles('0.17.0',)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/site-packages/nose/case.py", line 197, in runTest
    self.test(*self.arg)
  File "/home/travis/build/parthea/pandas/pandas/io/tests/test_pickle.py", line 174, in read_pickles
    data = self.compare(vf, version)
  File "/home/travis/build/parthea/pandas/pandas/io/tests/test_pickle.py", line 75, in compare
    expected = self.data[typ][dt]
KeyError: 'period'
======================================================================
ERROR: pandas.io.tests.test_pickle.TestPickle.test_pickles('0.17.1',)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/site-packages/nose/case.py", line 197, in runTest
    self.test(*self.arg)
  File "/home/travis/build/parthea/pandas/pandas/io/tests/test_pickle.py", line 174, in read_pickles
    data = self.compare(vf, version)
  File "/home/travis/build/parthea/pandas/pandas/io/tests/test_pickle.py", line 75, in compare
    expected = self.data[typ][dt]
KeyError: 'period'
======================================================================
ERROR: pandas.io.tests.test_pickle.TestPickle.test_pickles('0.18.0',)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/site-packages/nose/case.py", line 197, in runTest
    self.test(*self.arg)
  File "/home/travis/build/parthea/pandas/pandas/io/tests/test_pickle.py", line 174, in read_pickles
    data = self.compare(vf, version)
  File "/home/travis/build/parthea/pandas/pandas/io/tests/test_pickle.py", line 75, in compare
    expected = self.data[typ][dt]
KeyError: 'period'
======================================================================
ERROR: pandas.io.tests.test_pickle.TestPickle.test_pickles('0.18.1',)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/travis/miniconda/envs/pandas/lib/python2.7/site-packages/nose/case.py", line 197, in runTest
    self.test(*self.arg)
  File "/home/travis/build/parthea/pandas/pandas/io/tests/test_pickle.py", line 174, in read_pickles
    data = self.compare(vf, version)
  File "/home/travis/build/parthea/pandas/pandas/io/tests/test_pickle.py", line 75, in compare
    expected = self.data[typ][dt]
KeyError: 'period'
----------------------------------------------------------------------
```
 u need to push tags to your master branch 
 > u need to push tags to your master branch

@jreback  Thanks! That was it.

All tests pass in [this PR](https://github.com/parthea/pandas/pull/2) from my forked repo.

Only the first commit (89e709154b0417df163c93d33c3f3aecea624551) should be merged . The second commit contains a credentials file which was encrypted from my forked repo (55821a65da69193e8e471944e9b0074474b290d8) and won't be required.

If you want to see that Travis is green prior to merging, one solution is to create a branch from pydata/pandas and merge commit (89e709154b0417df163c93d33c3f3aecea624551) into that branch. I expect the correct (pydata/pandas) credentials will work since the branch is not from a different(forked) repo.
 @jreback Ready for review. Travis is green at parthea/pandas#2 
 ok the first commit contains the correct credentials? 
 Yes. The first commit contains the correct credentials from parthea/pandas#1 

Only merge the first commit. If its not too much trouble, you could create a PR from pydata/pandas and merge only the first commit just to make sure. The credentials should work since the PR branch is not from a forked repo.
 np

I am going to (later) push this up as a PR on master itself so should build 
 the only thing is we may need to put in a check to skip trying to get these credentials when not on the master branch
 ## [Current coverage](https://codecov.io/gh/pydata/pandas/pull/14111?src=pr) is 85.27% (diff: 100%)

> Merging [#14111](https://codecov.io/gh/pydata/pandas/pull/14111?src=pr) into [master](https://codecov.io/gh/pydata/pandas/branch/master?src=pr) will not change coverage

``` diff
@@             master     #14111   diff @@
==========================================
  Files           139        139          
  Lines         50511      50511          
  Methods           0          0          
  Messages          0          0          
  Branches          0          0          
==========================================
  Hits          43071      43071          
  Misses         7440       7440          
  Partials          0          0          
```

> Powered by [Codecov](https://codecov.io?src=pr). Last update [10bf721...1a13487](https://codecov.io/gh/pydata/pandas/compare/10bf7213240eaa0960f50f86c7790d64d8973060...1a13487e594625f76041da5fe418e15b052a7709?src=pr)
 > the only thing is we may need to put in a check to skip trying to get these credentials when not on the master branch

Done

Tests are skipped when the encryption key is not available on Travis. See https://travis-ci.org/pydata/pandas/builds/156106141

```
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
#25 pandas.io.tests.test_gbq.GBQUnitTests.test_read_gbq_with_corrupted_private_key_json_should_fail: Cannot run integration tests without a private key json file path
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------
#26 pandas.io.tests.test_gbq.TestGBQConnectorIntegration.test_get_application_default_credentials_does_not_throw_error: Cannot run integration tests without a project id
#27 pandas.io.tests.test_gbq.TestGBQConnectorIntegration.test_get_application_default_credentials_returns_credentials: Cannot run integration tests without a project id
#28 pandas.io.tests.test_gbq.TestGBQConnectorIntegration.test_should_be_able_to_get_a_bigquery_service: Cannot run integration tests without a project id
#29 pandas.io.tests.test_gbq.TestGBQConnectorIntegration.test_should_be_able_to_get_results_from_query: Cannot run integration tests without a project id
#30 pandas.io.tests.test_gbq.TestGBQConnectorIntegration.test_should_be_able_to_get_schema_from_query: Cannot run integration tests without a project id
#31 pandas.io.tests.test_gbq.TestGBQConnectorIntegration.test_should_be_able_to_get_valid_credentials: Cannot run integration tests without a project id
#32 pandas.io.tests.test_gbq.TestGBQConnectorIntegration.test_should_be_able_to_make_a_connector: Cannot run integration tests without a project id
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
#33 pandas.io.tests.test_gbq.TestGBQConnectorServiceAccountKeyContentsIntegration.test_should_be_able_to_get_a_bigquery_service: Cannot run integration tests without a project id
#34 pandas.io.tests.test_gbq.TestGBQConnectorServiceAccountKeyContentsIntegration.test_should_be_able_to_get_results_from_query: Cannot run integration tests without a project id
#35 pandas.io.tests.test_gbq.TestGBQConnectorServiceAccountKeyContentsIntegration.test_should_be_able_to_get_schema_from_query: Cannot run integration tests without a project id
#36 pandas.io.tests.test_gbq.TestGBQConnectorServiceAccountKeyContentsIntegration.test_should_be_able_to_get_valid_credentials: Cannot run integration tests without a project id
#37 pandas.io.tests.test_gbq.TestGBQConnectorServiceAccountKeyContentsIntegration.test_should_be_able_to_make_a_connector: Cannot run integration tests without a project id
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
#38 pandas.io.tests.test_gbq.TestGBQConnectorServiceAccountKeyPathIntegration.test_should_be_able_to_get_a_bigquery_service: Cannot run integration tests without a project id
#39 pandas.io.tests.test_gbq.TestGBQConnectorServiceAccountKeyPathIntegration.test_should_be_able_to_get_results_from_query: Cannot run integration tests without a project id
#40 pandas.io.tests.test_gbq.TestGBQConnectorServiceAccountKeyPathIntegration.test_should_be_able_to_get_schema_from_query: Cannot run integration tests without a project id
#41 pandas.io.tests.test_gbq.TestGBQConnectorServiceAccountKeyPathIntegration.test_should_be_able_to_get_valid_credentials: Cannot run integration tests without a project id
#42 pandas.io.tests.test_gbq.TestGBQConnectorServiceAccountKeyPathIntegration.test_should_be_able_to_make_a_connector: Cannot run integration tests without a project id
---------------------------------------------------------------------------------------------------------------------
#43 <nose.suite.ContextSuite context=TestReadGBQIntegration>:setup: Cannot run integration tests without a project id
#44 <nose.suite.ContextSuite context=TestToGBQIntegration>:setup: Cannot run integration tests without a project id
#45 <nose.suite.ContextSuite context=TestToGBQIntegrationServiceAccountKeyContents>:setup: Cannot run integration tests without a project id
#46 <nose.suite.ContextSuite context=TestToGBQIntegrationServiceAccountKeyPath>:setup: Cannot run integration tests without a project id
```
 @parthea ok I pushed up that 1st commit.

pls check out the build and see if it works. ideally we could have some instructions for users to test on their forks as well ....any ideas?
 @parthea I am not sure this worked: https://travis-ci.org/pydata/pandas/jobs/156506548
 It appears to be working. The following 2 tests are supposed to be skipped:

```
pandas.io.tests.test_gbq.TestGBQConnectorIntegration.test_get_application_default_credentials_returns_credentials: Cannot get default_credentials from the environment!
---------------------------------------------------------------------------------------------------------------------------------
#43 pandas.io.tests.test_gbq.TestReadGBQIntegration.test_should_read_as_user_account: Cannot run local auth in travis environment
--------------------------------------------------------------------------------------------------
```

The first test only works with a Google Environment, and the 2nd test can't be automated (we use a service account).

I'll look into adding a PR to update the contributing documentation.
 ahh ok great!. So at the very least a change that doesn't pass the integration tests will at least fail master!. great!
 I've added instructions for users to run Google BigQuery integration tests on their forks in #14144
