Migrate tests from Python 3.4 to Python 3.7

src/python/grpcio_tests/commands.py

@@ -130,7 +130,9 @@ class TestGevent(setuptools.Command):
         # Beta API is unsupported for gevent
         'protoc_plugin.beta_python_plugin_test',
         'unit.beta._beta_features_test',
-    )
+        # TODO(https://github.com/grpc/grpc/issues/15411) unpin gevent version
+        # This test will stuck while running higher version of gevent
+        'unit._auth_context_test.AuthContextTest.testSessionResumption')
     description = 'run tests with gevent.  Assumes grpc/gevent are installed'
     user_options = []
 

tools/run_tests/helper_scripts/build_python.sh

@@ -149,10 +149,13 @@ pip_install_dir() {
 }
 
 case "$VENV" in
-  *gevent*)
+  *py35_gevent*)
   # TODO(https://github.com/grpc/grpc/issues/15411) unpin this
   $VENV_PYTHON -m pip install gevent==1.3.b1
   ;;
+  *gevent*)
+  $VENV_PYTHON -m pip install -U gevent
+  ;;
 esac
 
 $VENV_PYTHON -m pip install --upgrade pip==10.0.1

tools/run_tests/run_tests.py

@@ -765,8 +765,10 @@ class PythonLanguage(object):
             return 'stretch_' + self.args.compiler[len('python'):]
         elif self.args.compiler == 'python_alpine':
             return 'alpine'
-        else:
+        elif self.args.compiler == 'python3.4':
             return 'jessie'
+        else:
+            return 'stretch_3.7'
 
     def _get_pythons(self, args):
         if args.arch == 'x86':
@@ -844,7 +846,7 @@ class PythonLanguage(object):
             else:
                 return (
                     python27_config,
-                    python34_config,
+                    python37_config,
                 )
         elif args.compiler == 'python2.7':
             return (python27_config,)