Remove 3.5 and xenial support (SC-711) (#1167)

Includes:
 - Update tox.ini and .travis.yml accordingly
 - Cleanup tox.ini with new tox syntax and cloud-init dependencies
 - Update documentation accordingly
 - Replace/remove xenial references where additional testing isn't required
 - Remove xenial checks in integration tests
 - Replace yield_fixture with fixture in pytest tests

Sections of code commented with lines like "Remove when Xenial is no
longer supported" still exist as they're require additional testing.

10 files changed, 13 insertions, 13 deletions

diff --git a/tests/unittests/cmd/devel/test_hotplug_hook.py b/tests/unittests/cmd/devel/test_hotplug_hook.py
index 842e8dfd..5ecb5969 100644
--- a/tests/unittests/cmd/devel/test_hotplug_hook.py
+++ b/tests/unittests/cmd/devel/test_hotplug_hook.py
@@ -16,7 +16,7 @@ hotplug_args = namedtuple("hotplug_args", "udevaction, subsystem, devpath")
 FAKE_MAC = "11:22:33:44:55:66"
 
 
-@pytest.yield_fixture
+@pytest.fixture
 def mocks():
     m_init = mock.MagicMock(spec=Init)
     m_distro = mock.MagicMock(spec=Distro)
diff --git a/tests/unittests/config/test_cc_install_hotplug.py b/tests/unittests/config/test_cc_install_hotplug.py
index 3bd44aba..e67fce60 100644
--- a/tests/unittests/config/test_cc_install_hotplug.py
+++ b/tests/unittests/config/test_cc_install_hotplug.py
@@ -12,7 +12,7 @@ from cloudinit.config.cc_install_hotplug import (
 from cloudinit.event import EventScope, EventType
 
 
-@pytest.yield_fixture()
+@pytest.fixture()
 def mocks():
     m_update_enabled = mock.patch("cloudinit.stages.update_event_enabled")
     m_write = mock.patch("cloudinit.util.write_file", autospec=True)
diff --git a/tests/unittests/distros/test_networking.py b/tests/unittests/distros/test_networking.py
index 635f6901..274647cb 100644
--- a/tests/unittests/distros/test_networking.py
+++ b/tests/unittests/distros/test_networking.py
@@ -13,7 +13,7 @@ from cloudinit.distros.networking import (
 )
 
 
-@pytest.yield_fixture
+@pytest.fixture
 def generic_networking_cls():
     """Returns a direct Networking subclass which errors on /sys usage.
 
@@ -40,7 +40,7 @@ def generic_networking_cls():
         yield TestNetworking
 
 
-@pytest.yield_fixture
+@pytest.fixture
 def sys_class_net(tmpdir):
     sys_class_net_path = tmpdir.join("sys/class/net")
     sys_class_net_path.ensure_dir()
diff --git a/tests/unittests/sources/test_lxd.py b/tests/unittests/sources/test_lxd.py
index ad1508a0..e11c3746 100644
--- a/tests/unittests/sources/test_lxd.py
+++ b/tests/unittests/sources/test_lxd.py
@@ -57,7 +57,7 @@ def lxd_metadata():
     return LXD_V1_METADATA
 
 
-@pytest.yield_fixture
+@pytest.fixture
 def lxd_ds(request, paths, lxd_metadata):
     """
     Return an instantiated DataSourceLXD.
diff --git a/tests/unittests/sources/test_oracle.py b/tests/unittests/sources/test_oracle.py
index e0e79c8c..356b3738 100644
--- a/tests/unittests/sources/test_oracle.py
+++ b/tests/unittests/sources/test_oracle.py
@@ -93,7 +93,7 @@ def metadata_version():
     return 2
 
 
-@pytest.yield_fixture
+@pytest.fixture
 def oracle_ds(request, fixture_utils, paths, metadata_version):
     """
     Return an instantiated DataSourceOracle.
@@ -649,7 +649,7 @@ class TestCommon_GetDataBehaviour:
     separate class for that case.)
     """
 
-    @pytest.yield_fixture(params=[True, False])
+    @pytest.fixture(params=[True, False])
     def parameterized_oracle_ds(self, request, oracle_ds):
         """oracle_ds parameterized for iSCSI and non-iSCSI root respectively"""
         is_iscsi_root = request.param
diff --git a/tests/unittests/sources/test_vmware.py b/tests/unittests/sources/test_vmware.py
index dcdbda89..dd331349 100644
--- a/tests/unittests/sources/test_vmware.py
+++ b/tests/unittests/sources/test_vmware.py
@@ -57,7 +57,7 @@ runcmd:
 """
 
 
-@pytest.yield_fixture(autouse=True)
+@pytest.fixture(autouse=True)
 def common_patches():
     with mock.patch("cloudinit.util.platform.platform", return_value="Linux"):
         with mock.patch.multiple(
diff --git a/tests/unittests/test_features.py b/tests/unittests/test_features.py
index 141de55b..794a9654 100644
--- a/tests/unittests/test_features.py
+++ b/tests/unittests/test_features.py
@@ -12,7 +12,7 @@ import pytest
 import cloudinit
 
 
-@pytest.yield_fixture()
+@pytest.fixture()
 def create_override(request):
     """
     Create a feature overrides file and do some module wizardry to make
diff --git a/tests/unittests/test_net_activators.py b/tests/unittests/test_net_activators.py
index 0e3ab43f..3c29e2f7 100644
--- a/tests/unittests/test_net_activators.py
+++ b/tests/unittests/test_net_activators.py
@@ -39,7 +39,7 @@ NETPLAN_CALL_LIST = [
 ]
 
 
-@pytest.yield_fixture
+@pytest.fixture
 def available_mocks():
     mocks = namedtuple("Mocks", "m_which, m_file")
     with patch("cloudinit.subp.which", return_value=True) as m_which:
@@ -47,7 +47,7 @@ def available_mocks():
             yield mocks(m_which, m_file)
 
 
-@pytest.yield_fixture
+@pytest.fixture
 def unavailable_mocks():
     mocks = namedtuple("Mocks", "m_which, m_file")
     with patch("cloudinit.subp.which", return_value=False) as m_which:
diff --git a/tests/unittests/test_stages.py b/tests/unittests/test_stages.py
index be1a0787..3214410b 100644
--- a/tests/unittests/test_stages.py
+++ b/tests/unittests/test_stages.py
@@ -512,7 +512,7 @@ class TestInit_InitializeFilesystem:
     TODO: Expand these tests to cover all of _initialize_filesystem's behavior.
     """
 
-    @pytest.yield_fixture
+    @pytest.fixture
     def init(self, paths):
         """A fixture which yields a stages.Init instance with paths and cfg set
 
diff --git a/tests/unittests/test_util.py b/tests/unittests/test_util.py
index e2bfe9d2..3765511b 100644
--- a/tests/unittests/test_util.py
+++ b/tests/unittests/test_util.py
@@ -1127,7 +1127,7 @@ class TestMountCb:
     TODO: Test the if/else branch that actually performs the mounting operation
     """
 
-    @pytest.yield_fixture
+    @pytest.fixture
     def already_mounted_device_and_mountdict(self):
         """Mock an already-mounted device, and yield (device, mount dict)"""
         device = "/dev/fake0"