diff --git a/sysdata/tests/test_config.py b/sysdata/tests/test_config.py
index d7ffbf9afa..2035371392 100644
--- a/sysdata/tests/test_config.py
+++ b/sysdata/tests/test_config.py
@@ -1,7 +1,6 @@
 from sysdata.config.configdata import Config
 from sysdata.config.control_config import get_control_config
 from sysdata.config.private_directory import PRIVATE_CONFIG_DIR_ENV_VAR
-import os
 
 
 class TestConfig:
@@ -11,16 +10,16 @@ def test_default(self):
         assert config.get_element("ib_idoffset") == 100
 
     def test_custom_dir(self, monkeypatch):
-        envs = {PRIVATE_CONFIG_DIR_ENV_VAR: "sysdata.tests.custom_private_config"}
-        monkeypatch.setattr(os, "environ", envs)
+        monkeypatch.setenv(
+            PRIVATE_CONFIG_DIR_ENV_VAR, "sysdata.tests.custom_private_config"
+        )
 
         Config.reset()
         config = Config.default_config()
         assert config.get_element("ib_idoffset") == 1000
 
     def test_bad_custom_dir(self, monkeypatch):
-        envs = {PRIVATE_CONFIG_DIR_ENV_VAR: "sysdata.tests"}
-        monkeypatch.setattr(os, "environ", envs)
+        monkeypatch.setenv(PRIVATE_CONFIG_DIR_ENV_VAR, "sysdata.tests")
 
         Config.reset()
         config = Config.default_config()
@@ -34,8 +33,9 @@ def test_default_control(self):
         )
 
     def test_control_custom_dir(self, monkeypatch):
-        envs = {PRIVATE_CONFIG_DIR_ENV_VAR: "sysdata.tests.custom_private_config"}
-        monkeypatch.setattr(os, "environ", envs)
+        monkeypatch.setenv(
+            PRIVATE_CONFIG_DIR_ENV_VAR, "sysdata.tests.custom_private_config"
+        )
 
         config = get_control_config()
         assert (
@@ -44,8 +44,7 @@ def test_control_custom_dir(self, monkeypatch):
         )
 
     def test_control_bad_custom_dir(self, monkeypatch):
-        envs = {PRIVATE_CONFIG_DIR_ENV_VAR: "sysdata.tests"}
-        monkeypatch.setattr(os, "environ", envs)
+        monkeypatch.setenv(PRIVATE_CONFIG_DIR_ENV_VAR, "sysdata.tests")
 
         config = get_control_config()
         assert (
diff --git a/systems/accounts/curves/account_curve.py b/systems/accounts/curves/account_curve.py
index 9e238958d4..af746eeb4e 100644
--- a/systems/accounts/curves/account_curve.py
+++ b/systems/accounts/curves/account_curve.py
@@ -277,7 +277,7 @@ def sortino(self):
         return sortino
 
     def vals(self):
-        vals = self.values[~np.isnan(self.values)]
+        vals = pd.to_numeric(self.values[~pd.isnull(self.values)], errors="coerce")
 
         return vals
 
diff --git a/systems/tests/test_position_sizing.py b/systems/tests/test_position_sizing.py
index b0676dc816..b81025b357 100644
--- a/systems/tests/test_position_sizing.py
+++ b/systems/tests/test_position_sizing.py
@@ -29,6 +29,9 @@ def setUp(self):
         self.data = data
         self.position_sizing = PositionSizing
 
+    def tearDown(self) -> None:
+        self.monkeypatch.undo()
+
     @unittest.SkipTest
     def test_get_combined_forecast(self):
         self.assertAlmostEqual(
@@ -60,8 +63,9 @@ def test_get_instrument_sizing_data(self):
         self.assertEqual(ans[1], 2500)
 
     def test_get_daily_cash_vol_target(self):
-        envs = {PRIVATE_CONFIG_DIR_ENV_VAR: "sysdata.tests.custom_private_config"}
-        self.monkeypatch.setattr(os, "environ", envs)
+        self.monkeypatch.setenv(
+            PRIVATE_CONFIG_DIR_ENV_VAR, "sysdata.tests.custom_private_config"
+        )
 
         ans_dict = self.system.positionSize.get_vol_target_dict()
         self.assertEqual(ans_dict["base_currency"], "GBP")