Making nox skip unchanged samples. (#327)

Author: Jon Wayne Parrott

nox.py

@@ -14,6 +14,7 @@
 
 import fnmatch
 import os
+import subprocess
 import tempfile
 
 import nox
@@ -26,17 +27,8 @@
     '.coveragerc', '--cov-append', '--cov-report=']
 
 # Speech is temporarily disabled.
-SESSION_TESTS_BLACKLIST = set(('appengine', 'testing', 'speech'))
-
-
-def session_lint(session):
-    session.install('flake8', 'flake8-import-order')
-    session.run(
-        'flake8', '--builtin=gettext', '--max-complexity=10',
-        '--import-order-style=google',
-        '--exclude',
-        'container_engine/django_tutorial/polls/migrations/*,.nox,.cache,env',
-        *(session.posargs or ['.']))
+TESTS_BLACKLIST = set(('appengine', 'testing', 'speech'))
+APPENGINE_BLACKLIST = set()
 
 
 def list_files(folder, pattern):
@@ -46,18 +38,6 @@ def list_files(folder, pattern):
                 yield os.path.join(root, filename)
 
 
-def session_reqcheck(session):
-    session.install(REPO_TOOLS_REQ)
-
-    if 'update' in session.posargs:
-        command = 'update-requirements'
-    else:
-        command = 'check-requirements'
-
-    for reqfile in list_files('.', 'requirements*.txt'):
-        session.run('gcprepotools', command, reqfile)
-
-
 def collect_sample_dirs(start_dir, blacklist=set()):
     """Recursively collects a list of dirs that contain tests."""
     # Collect all the directories that have tests in them.
@@ -73,37 +53,37 @@ def collect_sample_dirs(start_dir, blacklist=set()):
                           if s[0].isalpha() and s not in blacklist]
 
 
-@nox.parametrize('interpreter', ['python2.7', 'python3.4'])
-def session_tests(session, interpreter, extra_pytest_args=None):
-    session.interpreter = interpreter
-    session.install(REPO_TOOLS_REQ)
-    session.install('-r', 'requirements-{}-dev.txt'.format(interpreter))
+def get_changed_files():
+    pr = os.environ.get('TRAVIS_PULL_REQUEST')
+    if pr == 'false':
+        # This is not a pull request.
+        changed = subprocess.check_output(
+            ['git', 'show', '--pretty=format:', '--name-only',
+                os.environ.get('TRAVIS_COMMIT_RANGE')])
+    elif pr is not None:
+        changed = subprocess.check_output(
+            ['git', 'diff', '--name-only',
+                os.environ.get('TRAVIS_COMMIT'),
+                os.environ.get('TRAVIS_BRANCH')])
+    else:
+        changed = ''
+        print('Uh... where are we?')
+    return set([x for x in changed.split('\n') if x])
 
-    # extra_pytest_args can be send by another session calling this session,
-    # see session_travis.
-    pytest_args = COMMON_PYTEST_ARGS + (extra_pytest_args or [])
 
-    # session.posargs is any leftover arguments from the command line, which
-    # allows users to run a particular test instead of all of them.
-    for sample in (session.posargs or
-                   collect_sample_dirs('.', SESSION_TESTS_BLACKLIST)):
+def filter_samples(sample_dirs, changed_files):
+    result = []
+    for sample_dir in sample_dirs:
+        if sample_dir.startswith('./'):
+            sample_dir = sample_dir[2:]
+        for changed_file in changed_files:
+            if changed_file.startswith(sample_dir):
+                result.append(sample_dir)
 
-        # Install additional dependencies if they exist
-        dirname = sample if os.path.isdir(sample) else os.path.dirname(sample)
-        for reqfile in list_files(dirname, 'requirements*.txt'):
-            session.install('-r', reqfile)
+    return result
 
-        session.run(
-            'py.test', sample,
-            *pytest_args,
-            success_codes=[0, 5])  # Treat no test collected as success.
-
-
-def session_gae(session, extra_pytest_args=None):
-    session.interpreter = 'python2.7'
-    session.install(REPO_TOOLS_REQ)
-    session.install('-r', 'requirements-python2.7-dev.txt')
 
+def setup_appengine(session):
     # Install the app engine sdk and setup import paths.
     gae_root = os.environ.get('GAE_ROOT', tempfile.gettempdir())
     session.env['PYTHONPATH'] = os.path.join(gae_root, 'google_appengine')
@@ -114,10 +94,42 @@ def session_gae(session, extra_pytest_args=None):
     if not os.path.exists('lib'):
         os.makedirs('lib')
 
-    pytest_args = COMMON_PYTEST_ARGS + (extra_pytest_args or [])
 
-    for sample in (session.posargs or collect_sample_dirs('appengine')):
+def run_tests_in_sesssion(
+        session, interpreter, use_appengine=False, skip_flaky=False,
+        changed_only=False):
+    session.interpreter = interpreter
+    session.install(REPO_TOOLS_REQ)
+    session.install('-r', 'requirements-{}-dev.txt'.format(interpreter))
+
+    if use_appengine:
+        setup_appengine(session)
+        sample_root = 'appengine'
+    else:
+        sample_root = '.'
+
+    pytest_args = COMMON_PYTEST_ARGS[:]
+
+    if skip_flaky:
+        pytest_args.append('-m not slow and not flaky')
 
+    # session.posargs is any leftover arguments from the command line, which
+    # allows users to run a particular test instead of all of them.
+    if session.posargs:
+        sample_directories = session.posargs
+    else:
+        sample_directories = collect_sample_dirs(
+            sample_root,
+            TESTS_BLACKLIST if not use_appengine else APPENGINE_BLACKLIST)
+
+    if changed_only:
+        changed_files = get_changed_files()
+        sample_directories = filter_samples(
+            sample_directories, changed_files)
+        print('Running tests on a subset of samples: ')
+        print('\n'.join(sample_directories))
+
+    for sample in sample_directories:
         # Install additional dependencies if they exist
         dirname = sample if os.path.isdir(sample) else os.path.dirname(sample)
         for reqfile in list_files(dirname, 'requirements*.txt'):
@@ -129,15 +141,45 @@ def session_gae(session, extra_pytest_args=None):
             success_codes=[0, 5])  # Treat no test collected as success.
 
 
+@nox.parametrize('interpreter', ['python2.7', 'python3.4'])
+def session_tests(session, interpreter):
+    run_tests_in_sesssion(session, interpreter)
+
+
+def session_gae(session):
+    run_tests_in_sesssion(
+        session, 'python2.7', use_appengine=True)
+
+
 @nox.parametrize('subsession', ['gae', 'tests'])
 def session_travis(session, subsession):
     """On travis, just run with python3.4 and don't run slow or flaky tests."""
     if subsession == 'tests':
-        session_tests(
-            session,
-            'python3.4',
-            extra_pytest_args=['-m not slow and not flaky'])
+        run_tests_in_sesssion(
+            session, 'python3.4', skip_flaky=True, changed_only=True)
+    else:
+        run_tests_in_sesssion(
+            session, 'python2.7', use_appengine=True, skip_flaky=True,
+            changed_only=True)
+
+
+def session_lint(session):
+    session.install('flake8', 'flake8-import-order')
+    session.run(
+        'flake8', '--builtin=gettext', '--max-complexity=10',
+        '--import-order-style=google',
+        '--exclude',
+        'container_engine/django_tutorial/polls/migrations/*,.nox,.cache,env',
+        *(session.posargs or ['.']))
+
+
+def session_reqcheck(session):
+    session.install(REPO_TOOLS_REQ)
+
+    if 'update' in session.posargs:
+        command = 'update-requirements'
     else:
-        session_gae(
-            session,
-            extra_pytest_args=['-m not slow and not flaky'])
+        command = 'check-requirements'
+
+    for reqfile in list_files('.', 'requirements*.txt'):
+        session.run('gcprepotools', command, reqfile)