From 84c27465797b8df4dee29ee845a3c9cea8ed1953 Mon Sep 17 00:00:00 2001
From: Dominik Kriegner <dominik.kriegner@gmail.com>
Date: Wed, 28 Jun 2023 17:23:39 +0200
Subject: [PATCH] fix check_set_errors functions and improve tests

previously the test did not cover any property setter. Also the
check_set_errors function did not read back the additional termination
characters. check_set_errors now returns a list upon success as
required.
---
 pymeasure/instruments/mksinst/mks937b.py  |  3 ++-
 tests/instruments/mksinst/test_mks937b.py | 16 +++++++++++++---
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/pymeasure/instruments/mksinst/mks937b.py b/pymeasure/instruments/mksinst/mks937b.py
index ab2265abe1..9a752cf9eb 100644
--- a/pymeasure/instruments/mksinst/mks937b.py
+++ b/pymeasure/instruments/mksinst/mks937b.py
@@ -155,7 +155,8 @@ def check_set_errors(self):
         reply = self._re_response.search(ret)
         if reply:
             if reply.group('ack') == 'ACK':
-                return
+                self._check_extra_termination()
+                return []
         # no valid acknowledgement message found
         raise ValueError(f"invalid reply '{ret}' found in check_errors")
 
diff --git a/tests/instruments/mksinst/test_mks937b.py b/tests/instruments/mksinst/test_mks937b.py
index 4c9ea23aec..385b625dfa 100644
--- a/tests/instruments/mksinst/test_mks937b.py
+++ b/tests/instruments/mksinst/test_mks937b.py
@@ -57,8 +57,18 @@ def test_ion_gauge_status_invalid_channel():
             inst.ch_2.ion_gauge_status
 
 
-def test_unit():
-    """Verify the communication of the voltage getter."""
+def test_unit_setter():
+    """Verify the communication of the unit setter."""
+    with expected_protocol(
+        MKS937B,
+        [("@253U!TORR", "@253ACKTORR"),
+         (None, b"FF")],
+    ) as inst:
+        inst.unit = "Torr"
+
+
+def test_unit_getter():
+    """Verify the communication of the unit getter."""
     with expected_protocol(
         MKS937B,
         [("@253U?", "@253ACKTORR"),
@@ -68,7 +78,7 @@ def test_unit():
 
 
 def test_power_enabled():
-    """Verify the communication of the voltage getter."""
+    """Verify the communication of the channel power getter."""
     with expected_protocol(
         MKS937B,
         [("@253CP1?", "@253ACKON"),