diff --git a/tangostationcontrol/tangostationcontrol/test/test_statistics_writer.py b/tangostationcontrol/tangostationcontrol/test/test_statistics_writer.py
index 12f641e79367baf11188b259e69e7c4b4a939699..4b10230c8fca8c0773d085c6e42719b74dd7b2c3 100644
--- a/tangostationcontrol/tangostationcontrol/test/test_statistics_writer.py
+++ b/tangostationcontrol/tangostationcontrol/test/test_statistics_writer.py
@@ -12,22 +12,19 @@ from tangostationcontrol.statistics_writer import statistics_writer
 import sys
 from os.path import dirname
 from tempfile import TemporaryDirectory
+from unittest import mock
 
 class TestStatisticsWriter(base.TestCase):
-    def setUp(self):
-        # strip all command-line arguments to allow us to redefine them in the test
-        sys.argv = [sys.argv[0]]
-
     def test_sst(self):
         with TemporaryDirectory() as tmpdir:
-            sys.argv += ["--mode", "SST", "--file", dirname(__file__) + "/SDP_SST_statistics_packets.bin", "--output_dir", tmpdir]
-
-            with self.assertRaises(SystemExit):
-                statistics_writer.main()
+            new_sys_argv = [sys.argv[0], "--mode", "SST", "--file", dirname(__file__) + "/SDP_SST_statistics_packets.bin", "--output_dir", tmpdir]
+            with mock.patch.object(statistics_writer.sys, 'argv', new_sys_argv):
+                with self.assertRaises(SystemExit):
+                    statistics_writer.main()
 
     def test_xst(self):
         with TemporaryDirectory() as tmpdir:
-            sys.argv += ["--mode", "XST", "--file", dirname(__file__) + "/SDP_XST_statistics_packets.bin", "--output_dir", tmpdir]
-
-            with self.assertRaises(SystemExit):
-                statistics_writer.main()
+            new_sys_argv = [sys.argv[0], "--mode", "XST", "--file", dirname(__file__) + "/SDP_XST_statistics_packets.bin", "--output_dir", tmpdir]
+            with mock.patch.object(statistics_writer.sys, 'argv', new_sys_argv):
+                with self.assertRaises(SystemExit):
+                    statistics_writer.main()