chore: drop mention of Python 2.7 from templates (#1173)

Install async test dependencies unconditionally.

Drop unused 'samples' session. Samples are tested via separate noxfiles in all repos which have them.

Closes #1118.

Co-authored-by: Anthonios Partheniou <partheniou@google.com>

synthtool/gcp/common.py

@@ -225,17 +225,9 @@ def py_library(self, **kwargs) -> Path:
             kwargs["default_python_version"] = "3.8"
         if "unit_test_python_versions" not in kwargs:
             kwargs["unit_test_python_versions"] = ["3.6", "3.7", "3.8", "3.9"]
-            if "microgenerator" not in kwargs:
-                kwargs["unit_test_python_versions"] = ["2.7"] + kwargs[
-                    "unit_test_python_versions"
-                ]
 
         if "system_test_python_versions" not in kwargs:
             kwargs["system_test_python_versions"] = ["3.8"]
-            if "microgenerator" not in kwargs:
-                kwargs["system_test_python_versions"] = ["2.7"] + kwargs[
-                    "system_test_python_versions"
-                ]
 
         # If cov_level is not given, set it to None.
         if "cov_level" not in kwargs:

synthtool/gcp/templates/python_library/noxfile.py.j2

@@ -87,10 +87,8 @@ def default(session):
     constraints_path = str(
         CURRENT_DIRECTORY / "testing" / f"constraints-{session.python}.txt"
     )
-    {%- if microgenerator %}
-    session.install("asyncmock", "pytest-asyncio", "-c", constraints_path)
-    {% endif %}
-    session.install("mock", "pytest", "pytest-cov", {% for d in unit_test_external_dependencies %}"{{d}}",{% endfor %} "-c", constraints_path)
+    session.install("mock", "asyncmock", "pytest", "pytest-cov", "pytest-asyncio", "-c", constraints_path)
+    {% for d in unit_test_external_dependencies %}session.install("{{d}}", "-c", constraints_path){% endfor %}
     {% for dependency in unit_test_local_dependencies %}session.install("-e", "{{dependency}}", "-c", constraints_path)
     {% endfor %}
     {% for dependency in unit_test_dependencies %}session.install("-e", "{{dependency}}", "-c", constraints_path){% endfor %}
@@ -192,20 +190,6 @@ def system(session):
             *session.posargs
         )
 
-{% if samples_test %}
-@nox.session(python=["2.7", "3.7"])
-def samples(session):
-    requirements_path = os.path.join("samples", "requirements.txt")
-    requirements_exists = os.path.exists(requirements_path)
-
-    session.install("mock", "pytest")
-    if requirements_exists:
-        session.install("-r", requirements_path)
-    session.install("-e", ".")
-
-    session.run("py.test", "--quiet", "samples", *session.posargs)
-{% endif %}
-
 @nox.session(python=DEFAULT_PYTHON_VERSION)
 def cover(session):
     """Run the final coverage report.

synthtool/gcp/templates/python_library/scripts/readme-gen/templates/install_deps.tmpl.rst

@@ -12,7 +12,7 @@ Install Dependencies
    .. _Python Development Environment Setup Guide:
        https://cloud.google.com/python/setup
 
-#. Create a virtualenv. Samples are compatible with Python 2.7 and 3.4+.
+#. Create a virtualenv. Samples are compatible with Python 3.6+.
 
     .. code-block:: bash
 

synthtool/gcp/templates/python_samples/noxfile.py.j2

@@ -39,7 +39,7 @@ BLACK_VERSION = "black==19.10b0"
 
 TEST_CONFIG = {
     # You can opt out from the test for specific Python versions.
-    'ignored_versions': ["2.7"],
+    'ignored_versions': [],
 
     # Old samples are opted out of enforcing Python type hints
     # All new samples should feature them
@@ -88,8 +88,8 @@ def get_pytest_env_vars() -> Dict[str, str]:
 
 
 # DO NOT EDIT - automatically generated.
-# All versions used to tested samples.
-ALL_VERSIONS = ["2.7", "3.6", "3.7", "3.8", "3.9"]
+# All versions used to test samples.
+ALL_VERSIONS = ["3.6", "3.7", "3.8", "3.9"]
 
 # Any default versions that should be ignored.
 IGNORED_VERSIONS = TEST_CONFIG['ignored_versions']

synthtool/languages/python.py

@@ -15,7 +15,7 @@
 import re
 import sys
 from pathlib import Path
-from typing import Any, Dict
+from typing import Any, Dict, List
 
 import yaml
 
@@ -45,8 +45,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License."""
 
-SAMPLES_VERSIONS = ["2.7", "3.6", "3.7", "3.8"]
-IGNORED_VERSIONS = ["2.7"]
+SAMPLES_VERSIONS = ["3.6", "3.7", "3.8"]
+IGNORED_VERSIONS: List[str] = []
 
 SAMPLES_TEMPLATE_PATH = Path(CommonTemplates()._template_root) / "python_samples"