From abf1565a8d18baefe47290f4e0cb9f246c8c94ef Mon Sep 17 00:00:00 2001
From: bnavigator <code@bnavigator.de>
Date: Thu, 31 Dec 2020 00:25:23 +0100
Subject: [PATCH] Fix loading of defaults during pytest fixture setup

Also make matarrayout and matarrayin function scoped fixtures so
that they can set the warnings filters individually as needed for
each test.
---
 control/tests/config_test.py  |  2 +-
 control/tests/conftest.py     | 21 ++++++++++++++++++---
 control/tests/statesp_test.py | 16 +++++++++++++++-
 3 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/control/tests/config_test.py b/control/tests/config_test.py
index 3979ffca5..3b2a11f12 100644
--- a/control/tests/config_test.py
+++ b/control/tests/config_test.py
@@ -37,7 +37,7 @@ def test_get_param(self):
         assert ct.config._get_param('config', 'test1', None) == 1
         assert ct.config._get_param('config', 'test1', None, 1) == 1
 
-        ct.config.defaults['config.test3'] is None
+        ct.config.defaults['config.test3'] = None
         assert ct.config._get_param('config', 'test3') is None
         assert ct.config._get_param('config', 'test3', 1) == 1
         assert ct.config._get_param('config', 'test3', None, 1) is None
diff --git a/control/tests/conftest.py b/control/tests/conftest.py
index 7204c8f14..b67ef3674 100644
--- a/control/tests/conftest.py
+++ b/control/tests/conftest.py
@@ -28,7 +28,22 @@
                                                "PendingDeprecationWarning")
 
 
-@pytest.fixture(scope="session", autouse=TEST_MATRIX_AND_ARRAY,
+@pytest.fixture(scope="session", autouse=True)
+def control_defaults():
+    """Make sure the testing session always starts with the defaults.
+
+    This should be the first fixture initialized,
+    so that all other fixtures see the general defaults (unless they set them
+    themselves) even before importing control/__init__. Enforce this by adding
+    it as an argument to all other session scoped fixtures.
+    """
+    control.reset_defaults()
+    the_defaults = control.config.defaults.copy()
+    yield
+    # assert that nothing changed it without reverting
+    assert control.config.defaults == the_defaults
+
+@pytest.fixture(scope="function", autouse=TEST_MATRIX_AND_ARRAY,
                 params=[pytest.param("arrayout", marks=matrixerrorfilter),
                         pytest.param("matrixout", marks=matrixfilter)])
 def matarrayout(request):
@@ -70,7 +85,7 @@ def check_deprecated_matrix():
         yield
 
 
-@pytest.fixture(scope="session",
+@pytest.fixture(scope="function",
                 params=[p for p, usebydefault in
                         [(pytest.param(np.array,
                                        id="arrayin"),
@@ -90,7 +105,7 @@ def editsdefaults():
     """Make sure any changes to the defaults only last during a test"""
     restore = control.config.defaults.copy()
     yield
-    control.config.defaults.update(restore)
+    control.config.defaults = restore.copy()
 
 
 @pytest.fixture(scope="function")
diff --git a/control/tests/statesp_test.py b/control/tests/statesp_test.py
index c7b0a0aaf..23ccab555 100644
--- a/control/tests/statesp_test.py
+++ b/control/tests/statesp_test.py
@@ -16,7 +16,7 @@
 from control.dtime import sample_system
 from control.lti import evalfr
 from control.statesp import (StateSpace, _convertToStateSpace, drss, rss, ss,
-                             tf2ss)
+                             tf2ss, _statesp_defaults)
 from control.tests.conftest import ismatarrayout, slycotonly
 from control.xferfcn import TransferFunction, ss2tf
 
@@ -826,3 +826,17 @@ def test_returnScipySignalLTI_error(self, mimoss):
         with pytest.raises(ValueError):
             mimoss.returnScipySignalLTI(strict=True)
 
+
+class TestStateSpaceConfig:
+    """Test the configuration of the StateSpace module"""
+
+    @pytest.fixture
+    def matarrayout(self):
+        """Override autoused global fixture within this class"""
+        pass
+
+    def test_statespace_defaults(self, matarrayout):
+        """Make sure the tests are run with the configured defaults"""
+        for k, v in _statesp_defaults.items():
+            assert defaults[k] == v, \
+                "{} is {} but expected {}".format(k, defaults[k], v)