FEAT: Add docstring check to CI for an initial subset files

In this PR:    - Fixed omniscidb docstrings  - Fixed some docstrings
- Added pydocstyle check for ./ibis/.py and ./ibis/omniscidb/*.py
Current issues with pydocstyle:    -
PyCQA/pydocstyle#111  -
PyCQA/pydocstyle#363
Author: Ivan Ogasawara <ivan.ogasawara@gmail.com>

Closes #1996 from xmnlab/add-docstring-check and squashes the following commits:

bcda303 [Ivan Ogasawara] Fixed pydocstyle command.
55ff381 [Ivan Ogasawara] Add pydocstyle match-dir parameter into CI recipe.
5b270e8 [Ivan Ogasawara] Add docstring check to CI and git pre-commit hook

ci/azure/linux.yml

@@ -73,6 +73,10 @@ jobs:
     - bash: docker-compose run ibis flake8
       displayName: 'Lint'
 
+    # TODO: change match-dir when docstrings are fixed for other backends
+    - bash: docker-compose run ibis pydocstyle --match-dir="(ibis|omniscidb)"
+      displayName: "Docstring check"
+
     - bash: docker-compose run ibis black --check .
       displayName: 'Ensure black formatting'
       condition: ne(variables['PYTHON_NO_DOT_VERSION'], '35')

ci/requirements-3.5-dev.yml

@@ -28,6 +28,7 @@ dependencies:
   - pre_commit
   - psycopg2
   - pyarrow<0.12
+  - pydocstyle
   - pygit2
   - pymapd>=0.8.3,<0.11.0
   - pymysql

ci/requirements-3.6-dev.yml

@@ -26,6 +26,7 @@ dependencies:
   - psycopg2
   - pyarrow>=0.12
   - pydata-google-auth
+  - pydocstyle=4.0.1
   - pygit2
   - pymapd>=0.12.0
   - pymysql

ci/requirements-3.7-dev.yml

@@ -26,6 +26,7 @@ dependencies:
   - psycopg2
   - pyarrow>=0.12
   - pydata-google-auth
+  - pydocstyle=4.0.1
   - pygit2
   - pymapd>=0.12.0
   - pymysql

conftest.py

@@ -1,3 +1,4 @@
+"""Settings for tests."""
 import os
 from pathlib import Path
 
@@ -7,7 +8,15 @@
 
 
 @pytest.fixture(scope='session')
-def data_directory():
+def data_directory() -> Path:
+    """
+    Fixture that returns the test data directory.
+
+    Returns
+    -------
+    Path
+        Test data directory
+    """
     root = Path(__file__).absolute().parent
 
     default = root / 'ci' / 'ibis-testing-data'

ibis/__init__.py

@@ -1,3 +1,4 @@
+"""Initialize Ibis module."""
 from contextlib import suppress
 
 import ibis.config_init  # noqa: F401

ibis/_version.py

@@ -57,7 +57,7 @@ class NotThisMethod(Exception):
 
 
 def register_vcs_handler(vcs, method):  # decorator
-    """Decorator to mark a method as the handler for a particular VCS."""
+    """Mark a method as the handler for a particular VCS."""
     def decorate(f):
         """Store f in HANDLERS[vcs][method]."""
         if vcs not in HANDLERS: