Feat/close instruments (#376)

* Allow intruments to be used as contextmanagers

* Add unittest

* Remove unused imports

Co-authored-by: chris.grace <chris.grace@mastodondesign.com>

setup.cfg

@@ -37,6 +37,7 @@ install_requires =
     pyusb>=1.0
     pyvisa>=1.9
     ruamel.yaml>=0.16,<0.17
+    typing_extensions>=4.0.1
 
 [options.extras_require]
 numpy = numpy

src/instruments/abstract_instruments/comm/loopback_communicator.py

@@ -88,7 +88,8 @@ def close(self):
         Close connection to stdin
         """
         try:
-            self._stdin.close()
+            if self._stdin is not None:
+                self._stdin.close()
         except OSError:
             pass
 

src/instruments/abstract_instruments/instrument.py

@@ -10,6 +10,7 @@
 import collections
 import socket
 import struct
+import typing_extensions
 import urllib.parse as parse
 
 from serial import SerialException
@@ -718,3 +719,9 @@ def open_file(cls, filename):
         :return: Object representing the connected instrument.
         """
         return cls(FileCommunicator(filename))
+
+    def __enter__(self) -> typing_extensions.Self:
+        return self
+
+    def __exit__(self, *exc):
+        self._file.__exit__(*exc)

tests/test_base_instrument.py

@@ -484,6 +484,13 @@ def test_instrument_open_from_uri_invalid_scheme():
         _ = ik.Instrument.open_from_uri("foo://bar")
 
 
+@mock.patch("instruments.abstract_instruments.comm.LoopbackCommunicator.close")
+def test_instrument_context_manager(mock_close: mock.Mock):
+    with ik.Instrument.open_test():
+        pass
+    mock_close.assert_called()
+
+
 # INIT TESTS