Use pytest as default test runner, add test coverage

[AetherUnbound]

Change context

I've noticed that the README's instructions for running the unit tests has a custom test runner and requires installing the test dependencies explicitly. We've used pytest in the past with great success, so I thought I'd apply it here.

This changeset

This PR changes the default test runner to be pytest, and separates the test dependencies out into a separate extras group that can be installed with the .[<group>] syntax (e.g. pip install -e .[test]). The tests can either be run with pytest . or python setup.py test. Additionally, the tests also produce a coverage report available under build/coverage_html.

Example output of testing:

=============================================== test session starts ===============================================
platform linux -- Python 3.7.1, pytest-4.4.0, py-1.8.0, pluggy-0.9.0 -- /home/aether/programs/anaconda3/envs/labkey-api-python/bin/python
cachedir: .pytest_cache
rootdir: /home/aether/git/labkey-api-python, inifile: setup.cfg
plugins: cov-2.6.1
collected 103 items                                                                                               

test/test_domain.py::TestCreate::test_success PASSED                                                        [  0%]
test/test_domain.py::TestCreate::test_unauthorized PASSED                                                   [  1%]
test/test_domain.py::TestDrop::test_success PASSED                                                          [  2%]
test/test_domain.py::TestDrop::test_unauthorized PASSED                                                     [  3%]
test/test_domain.py::TestGet::test_success PASSED                                                           [  4%]
test/test_domain.py::TestGet::test_unauthorized PASSED                                                      [  5%]
test/test_domain.py::TestInferFields::test_success PASSED                                                   [  6%]
test/test_domain.py::TestInferFields::test_unauthorized PASSED                                              [  7%]
test/test_domain.py::TestSave::test_success PASSED                                                          [  8%]
test/test_domain.py::TestSave::test_unauthorized PASSED                                                     [  9%]
test/test_experiment_api.py::TestLoadBatch::test_general_error PASSED                                       [ 10%]
test/test_experiment_api.py::TestLoadBatch::test_query_not_found PASSED                                     [ 11%]
test/test_experiment_api.py::TestLoadBatch::test_server_not_found PASSED                                    [ 12%]
test/test_experiment_api.py::TestLoadBatch::test_success PASSED                                             [ 13%]
test/test_experiment_api.py::TestLoadBatch::test_unauthorized PASSED                                        [ 14%]
test/test_experiment_api.py::TestSaveBatch::test_general_error PASSED                                       [ 15%]
test/test_experiment_api.py::TestSaveBatch::test_query_not_found PASSED                                     [ 16%]
test/test_experiment_api.py::TestSaveBatch::test_server_not_found PASSED                                    [ 17%]
test/test_experiment_api.py::TestSaveBatch::test_success PASSED                                             [ 18%]
test/test_experiment_api.py::TestSaveBatch::test_unauthorized PASSED                                        [ 19%]
test/test_query_api.py::TestDeleteRows::test_general_error PASSED                                           [ 20%]
test/test_query_api.py::TestDeleteRows::test_query_not_found PASSED                                         [ 21%]
test/test_query_api.py::TestDeleteRows::test_server_not_found PASSED                                        [ 22%]
test/test_query_api.py::TestDeleteRows::test_success PASSED                                                 [ 23%]
test/test_query_api.py::TestDeleteRows::test_unauthorized PASSED                                            [ 24%]
test/test_query_api.py::TestUpdateRows::test_general_error PASSED                                           [ 25%]
test/test_query_api.py::TestUpdateRows::test_query_not_found PASSED                                         [ 26%]
test/test_query_api.py::TestUpdateRows::test_server_not_found PASSED                                        [ 27%]
test/test_query_api.py::TestUpdateRows::test_success PASSED                                                 [ 28%]
test/test_query_api.py::TestUpdateRows::test_unauthorized PASSED                                            [ 29%]
test/test_query_api.py::TestInsertRows::test_general_error PASSED                                           [ 30%]
test/test_query_api.py::TestInsertRows::test_query_not_found PASSED                                         [ 31%]
test/test_query_api.py::TestInsertRows::test_server_not_found PASSED                                        [ 32%]
test/test_query_api.py::TestInsertRows::test_success PASSED                                                 [ 33%]
test/test_query_api.py::TestInsertRows::test_unauthorized PASSED                                            [ 33%]
test/test_query_api.py::TestExecuteSQL::test_general_error PASSED                                           [ 34%]
test/test_query_api.py::TestExecuteSQL::test_query_not_found PASSED                                         [ 35%]
test/test_query_api.py::TestExecuteSQL::test_server_not_found PASSED                                        [ 36%]
test/test_query_api.py::TestExecuteSQL::test_success PASSED                                                 [ 37%]
test/test_query_api.py::TestExecuteSQL::test_unauthorized PASSED                                            [ 38%]
test/test_query_api.py::TestSelectRows::test_general_error PASSED                                           [ 39%]
test/test_query_api.py::TestSelectRows::test_query_not_found PASSED                                         [ 40%]
test/test_query_api.py::TestSelectRows::test_server_not_found PASSED                                        [ 41%]
test/test_query_api.py::TestSelectRows::test_success PASSED                                                 [ 42%]
test/test_query_api.py::TestSelectRows::test_unauthorized PASSED                                            [ 43%]
test/test_security.py::TestCreateUser::test_general_error PASSED                                            [ 44%]
test/test_security.py::TestCreateUser::test_query_not_found PASSED                                          [ 45%]
test/test_security.py::TestCreateUser::test_server_not_found PASSED                                         [ 46%]
test/test_security.py::TestCreateUser::test_success PASSED                                                  [ 47%]
test/test_security.py::TestCreateUser::test_unauthorized PASSED                                             [ 48%]
test/test_security.py::TestResetPassword::test_general_error PASSED                                         [ 49%]
test/test_security.py::TestResetPassword::test_query_not_found PASSED                                       [ 50%]
test/test_security.py::TestResetPassword::test_server_not_found PASSED                                      [ 51%]
test/test_security.py::TestResetPassword::test_success PASSED                                               [ 52%]
test/test_security.py::TestResetPassword::test_unauthorized PASSED                                          [ 53%]
test/test_security.py::TestActivateUsers::test_general_error PASSED                                         [ 54%]
test/test_security.py::TestActivateUsers::test_query_not_found PASSED                                       [ 55%]
test/test_security.py::TestActivateUsers::test_server_not_found PASSED                                      [ 56%]
test/test_security.py::TestActivateUsers::test_success PASSED                                               [ 57%]
test/test_security.py::TestActivateUsers::test_unauthorized PASSED                                          [ 58%]
test/test_security.py::TestDeactivateUsers::test_general_error PASSED                                       [ 59%]
test/test_security.py::TestDeactivateUsers::test_query_not_found PASSED                                     [ 60%]
test/test_security.py::TestDeactivateUsers::test_server_not_found PASSED                                    [ 61%]
test/test_security.py::TestDeactivateUsers::test_success PASSED                                             [ 62%]
test/test_security.py::TestDeactivateUsers::test_unauthorized PASSED                                        [ 63%]
test/test_security.py::TestDeleteUsers::test_general_error PASSED                                           [ 64%]
test/test_security.py::TestDeleteUsers::test_query_not_found PASSED                                         [ 65%]
test/test_security.py::TestDeleteUsers::test_server_not_found PASSED                                        [ 66%]
test/test_security.py::TestDeleteUsers::test_success PASSED                                                 [ 66%]
test/test_security.py::TestDeleteUsers::test_unauthorized PASSED                                            [ 67%]
test/test_security.py::TestAddToGroup::test_general_error PASSED                                            [ 68%]
test/test_security.py::TestAddToGroup::test_query_not_found PASSED                                          [ 69%]
test/test_security.py::TestAddToGroup::test_server_not_found PASSED                                         [ 70%]
test/test_security.py::TestAddToGroup::test_success PASSED                                                  [ 71%]
test/test_security.py::TestAddToGroup::test_unauthorized PASSED                                             [ 72%]
test/test_security.py::TestRemoveFromGroup::test_general_error PASSED                                       [ 73%]
test/test_security.py::TestRemoveFromGroup::test_query_not_found PASSED                                     [ 74%]
test/test_security.py::TestRemoveFromGroup::test_server_not_found PASSED                                    [ 75%]
test/test_security.py::TestRemoveFromGroup::test_success PASSED                                             [ 76%]
test/test_security.py::TestRemoveFromGroup::test_unauthorized PASSED                                        [ 77%]
test/test_security.py::TestRemoveFromRole::test_general_error PASSED                                        [ 78%]
test/test_security.py::TestRemoveFromRole::test_query_not_found PASSED                                      [ 79%]
test/test_security.py::TestRemoveFromRole::test_server_not_found PASSED                                     [ 80%]
test/test_security.py::TestRemoveFromRole::test_success PASSED                                              [ 81%]
test/test_security.py::TestRemoveFromRole::test_unauthorized PASSED                                         [ 82%]
test/test_security.py::TestAddToRole::test_general_error PASSED                                             [ 83%]
test/test_security.py::TestAddToRole::test_query_not_found PASSED                                           [ 84%]
test/test_security.py::TestAddToRole::test_server_not_found PASSED                                          [ 85%]
test/test_security.py::TestAddToRole::test_success PASSED                                                   [ 86%]
test/test_security.py::TestAddToRole::test_unauthorized PASSED                                              [ 87%]
test/test_security.py::TestGetRoles::test_general_error PASSED                                              [ 88%]
test/test_security.py::TestGetRoles::test_query_not_found PASSED                                            [ 89%]
test/test_security.py::TestGetRoles::test_server_not_found PASSED                                           [ 90%]
test/test_security.py::TestGetRoles::test_success PASSED                                                    [ 91%]
test/test_security.py::TestGetRoles::test_unauthorized PASSED                                               [ 92%]
test/test_security.py::TestListGroups::test_general_error PASSED                                            [ 93%]
test/test_security.py::TestListGroups::test_query_not_found PASSED                                          [ 94%]
test/test_security.py::TestListGroups::test_server_not_found PASSED                                         [ 95%]
test/test_security.py::TestListGroups::test_success PASSED                                                  [ 96%]
test/test_security.py::TestListGroups::test_unauthorized PASSED                                             [ 97%]
test/test_unsupported.py::TestPostMessage::test_success PASSED                                              [ 98%]
test/test_utils.py::TestJsonDumps::test_encoder PASSED                                                      [ 99%]
test/test_utils.py::TestJsonDumps::test_encoder_override PASSED                                             [100%]

----------- coverage: platform linux, python 3.7.1-final-0 -----------
Name                                 Stmts   Miss  Cover
--------------------------------------------------------
labkey/__init__.py                       5      0   100%
labkey/domain.py                       198    109    45%
labkey/exceptions.py                    33      3    91%
labkey/experiment.py                   130     32    75%
labkey/query.py                        124     32    74%
labkey/security.py                      59     12    80%
labkey/unsupported/__init__.py           0      0   100%
labkey/unsupported/messageboard.py      13      4    69%
labkey/unsupported/wiki.py              42     42     0%
labkey/utils.py                         97     19    80%
--------------------------------------------------------
TOTAL                                  701    253    64%
Coverage HTML written to dir build/coverage_html


=========================================== 103 passed in 0.51 seconds ============================================