From 9c9bf61ee3a1feb69a9a63d9198eeb258c41dde5 Mon Sep 17 00:00:00 2001
From: Felipe Monteiro <felipe.monteiro@att.com>
Date: Thu, 9 Aug 2018 19:46:23 +0100
Subject: [PATCH] fixtures: Introduce fixture for auto-resetting config object

Autouse fixtures in pytest are a powerful way of executing a
fixture for each test. Since Pegleg uses a global in-memory
object for storing config info, this dictionary should be
cleaned up after each test to ensure test idempotency.

The best way (and cleanest) is to use an autouse fixture inside
a conftest.py which ensures that it is used after each and every
unit test [0].

[0] https://docs.pytest.org/en/latest/fixture.html#conftest-py-sharing-fixture-functions

Change-Id: I0c647d3d7547d1bdcd7c289a4c11159376f9f58d
---
 src/bin/pegleg/tests/unit/conftest.py | 32 +++++++++++++++++++++++++++
 src/bin/pegleg/tests/unit/fixtures.py |  6 -----
 2 files changed, 32 insertions(+), 6 deletions(-)
 create mode 100644 src/bin/pegleg/tests/unit/conftest.py

diff --git a/src/bin/pegleg/tests/unit/conftest.py b/src/bin/pegleg/tests/unit/conftest.py
new file mode 100644
index 00000000..f2bda469
--- /dev/null
+++ b/src/bin/pegleg/tests/unit/conftest.py
@@ -0,0 +1,32 @@
+# Copyright 2018 AT&T Intellectual Property.  All other rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import copy
+
+import pytest
+
+from pegleg import config
+"""Fixtures that are applied to all unit tests."""
+
+
+@pytest.fixture(autouse=True)
+def restore_config():
+    """Used for ensuring the original global context is reset in memory
+    following each test execution. Simply import this file to use.
+    """
+    original_global_context = copy.deepcopy(config.GLOBAL_CONTEXT)
+    try:
+        yield
+    finally:
+        config.GLOBAL_CONTEXT = original_global_context
diff --git a/src/bin/pegleg/tests/unit/fixtures.py b/src/bin/pegleg/tests/unit/fixtures.py
index 8f33dfa7..0142611b 100644
--- a/src/bin/pegleg/tests/unit/fixtures.py
+++ b/src/bin/pegleg/tests/unit/fixtures.py
@@ -47,9 +47,6 @@ def _gen_document(**kwargs):
 def create_tmp_deployment_files(tmpdir):
     """Fixture that creates a temporary directory structure."""
     sitenames = ['cicd', 'lab']
-    # Used for ensuring the original global context is reset in memory
-    # following each test execution.
-    original_global_context = copy.deepcopy(config.GLOBAL_CONTEXT)
 
     SITE_TEST_STRUCTURE = {
         'directories': {
@@ -154,6 +151,3 @@ schema: pegleg/SiteDefinition/v1
         files._create_tree(cicd_path, tree=test_structure)
 
     yield
-
-    # Restore the global context back to blank slate status.
-    config.GLOBAL_CONTEXT = original_global_context