Add basic unit test for nmstate_apply

tests/test_apply.py

@@ -0,0 +1,58 @@
+#
+# Copyright 2020 Red Hat, Inc.
+#
+# This file is part of ansible-nmstate.
+#
+# ansible-nmstate is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# ansible-nmstate is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with ansible-nmstate.  If not, see <https://www.gnu.org/licenses/>.
+#
+
+""" unit tests for nmstate_apply.py """
+
+from unittest import mock
+
+from testlib import ANSIBLE_MOCK_MODULES
+
+
+with mock.patch.dict("sys.modules", ANSIBLE_MOCK_MODULES):
+    # E402 module level import not at top of file
+    import nmstate_apply  # noqa: E402
+
+
+def test_unchanged(base_state):
+    module_params = {"state": base_state}
+    nmstate_module, applied_state = run_module(module_params, base_state)
+    assert applied_state == base_state
+    assert not nmstate_module.result["changed"]
+
+
+def run_module(module_params, current_state):
+    ansible_module = mock.Mock()
+    ansible_module.check_mode = False
+    ansible_module.params = module_params
+
+    with mock.patch(
+        "ansible_nmstate.libnmstate.show", return_value=current_state
+    ) as mock_show:
+        nmstate_module = nmstate_apply.AnsibleNMStateApply(
+            ansible_module, "nmstate_apply_mock"
+        )
+        assert mock_show.called
+
+        with mock.patch("ansible_nmstate.libnmstate.apply") as mock_apply:
+            nmstate_module.run()
+
+    assert mock_show.call_count == 2
+    assert mock_apply.called
+    applied_state = mock_apply.call_args[0][0]
+    return nmstate_module, applied_state