chore: add pre-commit (#36)

* changes without context

        autosynth cannot find the source of changes triggered by earlier changes in this
        repository, or by version upgrades to tools such as linters.

* docs(python): fix intersphinx link for google-auth

Source-Author: Bu Sun Kim <8822365+busunkim96@users.noreply.github.com>
Source-Date: Thu Nov 19 10:16:05 2020 -0700
Source-Repo: googleapis/synthtool
Source-Sha: a073c873f3928c561bdf87fdfbf1d081d1998984
Source-Link: googleapis/synthtool@a073c87

* chore: add config / docs for 'pre-commit' support

Source-Author: Tres Seaver <tseaver@palladion.com>
Source-Date: Tue Dec 1 16:01:20 2020 -0500
Source-Repo: googleapis/synthtool
Source-Sha: 32af6da519a6b042e3da62008e2a75e991efb6b4
Source-Link: googleapis/synthtool@32af6da

* chore(deps): update precommit hook pre-commit/pre-commit-hooks to v3.3.0

Source-Author: WhiteSource Renovate <bot@renovateapp.com>
Source-Date: Wed Dec 2 17:18:24 2020 +0100
Source-Repo: googleapis/synthtool
Source-Sha: 69629b64b83c6421d616be2b8e11795738ec8a6c
Source-Link: googleapis/synthtool@69629b6

* test(python): give filesystem paths to pytest-cov

https://pytest-cov.readthedocs.io/en/latest/config.html

The pytest-cov docs seem to suggest a filesystem path is expected.

Source-Author: Bu Sun Kim <8822365+busunkim96@users.noreply.github.com>
Source-Date: Wed Dec 2 09:28:04 2020 -0700
Source-Repo: googleapis/synthtool
Source-Sha: f94318521f63085b9ccb43d42af89f153fb39f15
Source-Link: googleapis/synthtool@f943185

Co-authored-by: Bu Sun Kim <8822365+busunkim96@users.noreply.github.com>

packages/google-cloud-bigquery-connection/.pre-commit-config.yaml

@@ -0,0 +1,17 @@
+# See https://pre-commit.com for more information
+# See https://pre-commit.com/hooks.html for more hooks
+repos:
+-   repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v3.3.0
+    hooks:
+    -   id: trailing-whitespace
+    -   id: end-of-file-fixer
+    -   id: check-yaml
+-   repo: https://github.com/psf/black
+    rev: 19.10b0
+    hooks:
+    - id: black
+-   repo: https://gitlab.com/pycqa/flake8
+    rev: 3.8.4
+    hooks:
+    - id: flake8

packages/google-cloud-bigquery-connection/CONTRIBUTING.rst

@@ -111,6 +111,16 @@ Coding Style
   should point to the official ``googleapis`` checkout and the
   the branch should be the main branch on that remote (``master``).
 
+- This repository contains configuration for the
+  `pre-commit <https://pre-commit.com/>`__ tool, which automates checking
+  our linters during a commit.  If you have it installed on your ``$PATH``,
+  you can enable enforcing those checks via:
+
+.. code-block:: bash
+
+   $ pre-commit install
+   pre-commit installed at .git/hooks/pre-commit
+
 Exceptions to PEP8:
 
 - Many unit tests use a helper method, ``_call_fut`` ("FUT" is short for

packages/google-cloud-bigquery-connection/noxfile.py

@@ -81,9 +81,8 @@ def default(session):
     session.run(
         "py.test",
         "--quiet",
-        "--cov=google.cloud.bigqueryconnection",
-        "--cov=google.cloud",
-        "--cov=tests.unit",
+        "--cov=google/cloud",
+        "--cov=tests/unit",
         "--cov-append",
         "--cov-config=.coveragerc",
         "--cov-report=",

packages/google-cloud-bigquery-connection/synth.metadata

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/python-bigquery-connection.git",
-        "sha": "6e85354f33041ba8612207f7bac4e2313d982e8c"
+        "sha": "f3ce3aa826173bf61b3b79803d0231c27f89e6fa"
       }
     },
     {
@@ -19,14 +19,14 @@
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "9a7d9fbb7045c34c9d3d22c1ff766eeae51f04c9"
+        "sha": "f94318521f63085b9ccb43d42af89f153fb39f15"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "9a7d9fbb7045c34c9d3d22c1ff766eeae51f04c9"
+        "sha": "f94318521f63085b9ccb43d42af89f153fb39f15"
       }
     }
   ],
@@ -85,6 +85,7 @@
     ".kokoro/test-samples.sh",
     ".kokoro/trampoline.sh",
     ".kokoro/trampoline_v2.sh",
+    ".pre-commit-config.yaml",
     ".trampolinerc",
     "CODE_OF_CONDUCT.md",
     "CONTRIBUTING.rst",