Test Composer samples on Python 3 (GoogleCloudPlatform#1688)

* Test Composer samples on Python 3

Note: I had to skip the use_local_deps workflow sample because of a
change in relative versus absolute imports between Python 2 and Python
3. I have not yet checked the workflow within Airflow to see if it runs
under Python 3.

* Composer: Use slugify for unicode. Run local deps test in Python 3.

Author: tswast

.kokoro/presubmit_tests_composer.cfg

@@ -11,5 +11,13 @@ env_vars: {
 
 env_vars: {
     key: "NOX_SESSION"
-    value: "composer and py27 and not appengine"
+    value: "composer and py36 and not appengine"
+}
+
+# Explicitly use choose unicode dependency to let the apache-airflow package
+# installation continue. See:
+# https://github.com/apache/incubator-airflow/pull/3660
+env_vars: {
+    key: "SLUGIFY_USES_TEXT_UNIDECODE"
+    value: "yes"
 }

.travis.yml

@@ -12,6 +12,10 @@ cache:
   - "$HOME/.cache"
 env:
   global:
+    # Explicitly use choose unicode dependency to let the apache-airflow
+    # package installation continue. See:
+    # https://github.com/apache/incubator-airflow/pull/3660
+    - SLUGIFY_USES_TEXT_UNIDECODE=yes
     secure: fsBH64/WqTe7lRcn4awZU7q6+euS/LHgMq2Ee2ubaoxUei2GbK5jBgnGHxOKVL5sZ4KNfTc7d6NR5BB1ZouYr2v4q1ip7Il9kFG4g5qV4cIXzHusXkrjvIzQLupNpcD9JJZr1fmYh4AqXRs2kP/nZqb7xB6Jm/O+h+aeC1bhhBg=
 addons:
   apt:

composer/workflows/use_local_deps_test.py

@@ -12,6 +12,23 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import os.path
+import sys
+
+import pytest
+
+
+@pytest.fixture(scope='module', autouse=True)
+def local_deps():
+    """Add local directory to the PYTHONPATH to allow absolute imports.
+
+    Relative imports do not work in Airflow workflow definitions.
+    """
+    workflows_dir = os.path.abspath(os.path.dirname(__file__))
+    sys.path.append(workflows_dir)
+    yield
+    sys.path.remove(workflows_dir)
+
 
 def test_dag_import():
     """Test that the DAG file can be successfully imported.

nox.py

@@ -157,9 +157,7 @@ def _setup_appengine_sdk(session):
 GAE_STANDARD_SAMPLES = [
     sample for sample in ALL_TESTED_SAMPLES
     if sample.startswith('./appengine/standard/')]
-PY2_ONLY_SAMPLES = GAE_STANDARD_SAMPLES + [
-    sample for sample in ALL_TESTED_SAMPLES
-    if sample.startswith('./composer/workflows')]
+PY2_ONLY_SAMPLES = GAE_STANDARD_SAMPLES
 PY3_ONLY_SAMPLES = [
     sample for sample in ALL_TESTED_SAMPLES
     if (sample.startswith('./appengine/standard_python37')

testing/test-env.tmpl.sh

@@ -1,5 +1,6 @@
 # Environment variables for system tests.
 export GCLOUD_PROJECT=your-project-id
+export GOOGLE_CLOUD_PROJECT=$GCLOUD_PROJECT
 export CLOUD_STORAGE_BUCKET=$GCLOUD_PROJECT
 export API_KEY=
 export BIGTABLE_CLUSTER=bigtable-test