Add test coverage to ensure fileclient closes channel

tests/pytests/unit/test_fileclient.py

@@ -0,0 +1,48 @@
+import salt.fileclient
+from tests.support.mock import patch
+
+
+class MockReqChannel:
+    def factory(self, opts):
+        return self
+
+    def close(self):
+        return True
+
+    def send(self, load):
+        return self
+
+
+def test_fileclient_context_manager_closes(temp_salt_minion, temp_salt_master):
+    """
+    ensure fileclient channel closes
+    when used with a context manager
+    """
+    opts = temp_salt_minion.config.copy()
+    opts.update(
+        {
+            "id": "root",
+            "transport": "zeromq",
+            "auth_tries": 1,
+            "auth_timeout": 5,
+            "master_ip": "127.0.0.1",
+            "master_port": temp_salt_master.config["ret_port"],
+            "master_uri": "tcp://127.0.0.1:{}".format(
+                temp_salt_master.config["ret_port"]
+            ),
+        }
+    )
+    master_uri = "tcp://{master_ip}:{master_port}".format(
+        master_ip="localhost", master_port=opts["master_port"]
+    )
+    mock_reqchannel = MockReqChannel()
+    patch_reqchannel = patch.object(
+        salt.channel.client, "ReqChannel", return_value=mock_reqchannel
+    )
+    with patch_reqchannel:
+        with salt.fileclient.get_file_client(opts) as client:
+            client.master_opts()
+            assert not client._closing
+
+        assert client._closing
+        assert client.channel.close.called