From 6245b684210c51f26adad5316e8486f3edc6c76c Mon Sep 17 00:00:00 2001
From: Sondre Sortland <sonso@equinor.com>
Date: Mon, 17 Feb 2020 10:06:31 +0100
Subject: [PATCH] Fix environment manipulation in tests

---
 tests/all/plugins/test_plugin_context.py | 18 ++++++++++++------
 tests/conftest.py                        | 19 ++++++++++++++++++-
 2 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/tests/all/plugins/test_plugin_context.py b/tests/all/plugins/test_plugin_context.py
index 2d47ae3ba0e..7c740b8e8fc 100644
--- a/tests/all/plugins/test_plugin_context.py
+++ b/tests/all/plugins/test_plugin_context.py
@@ -2,9 +2,9 @@
 import os
 import sys
 import unittest
+from _pytest.monkeypatch import MonkeyPatch
 
 from ert_shared.plugins import ErtPluginContext
-
 import tests.all.plugins.dummy_plugins as dummy_plugins
 
 
@@ -18,8 +18,16 @@
 
 
 class PluginContextTest(unittest.TestCase):
+    def setUp(self):
+        self.monkeypatch = MonkeyPatch()
+        pass
+
+    def tearDown(self):
+        self.monkeypatch.undo()
+
     @unittest.skipIf(sys.version_info.major < 3, "Plugin Manager is Python 3 only")
     def test_no_plugins(self):
+        self.monkeypatch.delenv("ERT_SITE_CONFIG", raising=False)
         with ErtPluginContext(plugins=[]) as c:
             with self.assertRaises(KeyError):
                 os.environ["ECL100_SITE_CONFIG"]
@@ -42,6 +50,7 @@ def test_no_plugins(self):
 
     @unittest.skipIf(sys.version_info.major < 3, "Plugin Manager is Python 3 only")
     def test_with_plugins(self):
+        self.monkeypatch.delenv("ERT_SITE_CONFIG", raising=False)
         with ErtPluginContext(plugins=[dummy_plugins]) as c:
             with self.assertRaises(KeyError):
                 os.environ["ECL100_SITE_CONFIG"]
@@ -51,7 +60,7 @@ def test_with_plugins(self):
                 os.environ["FLOW_SITE_CONFIG"]
             with self.assertRaises(KeyError):
                 os.environ["RMS_SITE_CONFIG"]
-            
+
             self.assertTrue(os.path.isfile(os.environ["ERT_SITE_CONFIG"]))
             with open(os.environ["ERT_SITE_CONFIG"]) as f:
                 self.assertEqual(f.read(), c.plugin_manager.get_site_config_content())
@@ -65,7 +74,7 @@ def test_with_plugins(self):
     @unittest.skipIf(sys.version_info.major < 3, "Plugin Manager is Python 3 only")
     def test_already_set(self):
         for var in env_vars:
-            os.environ[var] = "TEST"
+            self.monkeypatch.setenv(var, "TEST")
 
         with ErtPluginContext(plugins=[dummy_plugins]) as c:
             for var in env_vars:
@@ -74,9 +83,6 @@ def test_already_set(self):
         for var in env_vars:
             self.assertEqual("TEST", os.environ[var])
 
-        for var in env_vars:
-            del os.environ[var]
-
     @unittest.skipIf(
         sys.version_info.major > 2, "Skipping Plugin Manager Python 2 test"
     )
diff --git a/tests/conftest.py b/tests/conftest.py
index 6b515214717..5aa741f922a 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,6 +1,7 @@
 import os
 import pytest
 
+
 @pytest.fixture()
 def source_root():
     path_list = os.path.dirname(os.path.abspath(__file__)).split("/")
@@ -9,4 +10,20 @@ def source_root():
         if os.path.isdir(git_path):
             return os.path.join(os.sep, *path_list)
         path_list.pop()
-    raise RuntimeError('Cannot find the source folder')
+    raise RuntimeError("Cannot find the source folder")
+
+
+@pytest.fixture(autouse=True)
+def env_save():
+    environment_pre = [
+        (key, val) for key, val in os.environ.items() if key != "PYTEST_CURRENT_TEST"
+    ]
+    yield
+    environment_post = [
+        (key, val) for key, val in os.environ.items() if key != "PYTEST_CURRENT_TEST"
+    ]
+    if set(environment_pre) != set(environment_post):
+        raise EnvironmentError(
+            "Your environment has changed after that test, please reset"
+        )
+