Fixed issue #16903 re exception with multiple simultanious writes (#17636)

Reworked tests/components/emulated_hue/test_init.py to not be
dependent on the specific internal implementation of util/jsonn.py

homeassistant/util/json.py

@@ -4,7 +4,7 @@ from typing import Union, List, Dict
 
 import json
 import os
-from os import O_WRONLY, O_CREAT, O_TRUNC
+import tempfile
 
 from homeassistant.exceptions import HomeAssistantError
 
@@ -46,13 +46,17 @@ def save_json(filename: str, data: Union[List, Dict],
 
     Returns True on success.
     """
-    tmp_filename = filename + "__TEMP__"
+    tmp_filename = ""
+    tmp_path = os.path.split(filename)[0]
     try:
         json_data = json.dumps(data, sort_keys=True, indent=4)
-        mode = 0o600 if private else 0o644
+        # Modern versions of Python tempfile create this file with mode 0o600
-        with open(os.open(tmp_filename, O_WRONLY | O_CREAT | O_TRUNC, mode),
+        with tempfile.NamedTemporaryFile(mode="w", encoding='utf-8',
-                  'w', encoding='utf-8') as fdesc:
+                                         dir=tmp_path, delete=False) as fdesc:
             fdesc.write(json_data)
+            tmp_filename = fdesc.name
+        if not private:
+            os.chmod(tmp_filename, 0o644)
         os.replace(tmp_filename, filename)
     except TypeError as error:
         _LOGGER.exception('Failed to serialize to JSON: %s',

tests/components/emulated_hue/test_init.py

@@ -1,7 +1,5 @@
 """Test the Emulated Hue component."""
-import json
+from unittest.mock import patch, Mock, MagicMock
-
-from unittest.mock import patch, Mock, mock_open, MagicMock
 
 from homeassistant.components.emulated_hue import Config
 
@@ -14,30 +12,30 @@ def test_config_google_home_entity_id_to_number():
         'type': 'google_home'
     })
 
-    mop = mock_open(read_data=json.dumps({'1': 'light.test2'}))
+    with patch('homeassistant.components.emulated_hue.load_json',
-    handle = mop()
+               return_value={'1': 'light.test2'}) as json_loader:
+        with patch('homeassistant.components.emulated_hue'
+                   '.save_json') as json_saver:
+            number = conf.entity_id_to_number('light.test')
+            assert number == '2'
 
-    with patch('homeassistant.util.json.open', mop, create=True):
+            assert json_saver.mock_calls[0][1][1] == {
-        with patch('homeassistant.util.json.os.open', return_value=0):
+                '1': 'light.test2', '2': 'light.test'
-            with patch('homeassistant.util.json.os.replace'):
+            }
-                number = conf.entity_id_to_number('light.test')
-                assert number == '2'
-                assert handle.write.call_count == 1
-                assert json.loads(handle.write.mock_calls[0][1][0]) == {
-                    '1': 'light.test2',
-                    '2': 'light.test',
-                }
 
-                number = conf.entity_id_to_number('light.test')
+            assert json_saver.call_count == 1
-                assert number == '2'
+            assert json_loader.call_count == 1
-                assert handle.write.call_count == 1
 
-                number = conf.entity_id_to_number('light.test2')
+            number = conf.entity_id_to_number('light.test')
-                assert number == '1'
+            assert number == '2'
-                assert handle.write.call_count == 1
+            assert json_saver.call_count == 1
 
-                entity_id = conf.number_to_entity_id('1')
+            number = conf.entity_id_to_number('light.test2')
-                assert entity_id == 'light.test2'
+            assert number == '1'
+            assert json_saver.call_count == 1
+
+            entity_id = conf.number_to_entity_id('1')
+            assert entity_id == 'light.test2'
 
 
 def test_config_google_home_entity_id_to_number_altered():
@@ -48,30 +46,30 @@ def test_config_google_home_entity_id_to_number_altered():
         'type': 'google_home'
     })
 
-    mop = mock_open(read_data=json.dumps({'21': 'light.test2'}))
+    with patch('homeassistant.components.emulated_hue.load_json',
-    handle = mop()
+               return_value={'21': 'light.test2'}) as json_loader:
+        with patch('homeassistant.components.emulated_hue'
+                   '.save_json') as json_saver:
+            number = conf.entity_id_to_number('light.test')
+            assert number == '22'
+            assert json_saver.call_count == 1
+            assert json_loader.call_count == 1
 
-    with patch('homeassistant.util.json.open', mop, create=True):
+            assert json_saver.mock_calls[0][1][1] == {
-        with patch('homeassistant.util.json.os.open', return_value=0):
+                '21': 'light.test2',
-            with patch('homeassistant.util.json.os.replace'):
+                '22': 'light.test',
-                number = conf.entity_id_to_number('light.test')
+            }
-                assert number == '22'
-                assert handle.write.call_count == 1
-                assert json.loads(handle.write.mock_calls[0][1][0]) == {
-                    '21': 'light.test2',
-                    '22': 'light.test',
-                }
 
-                number = conf.entity_id_to_number('light.test')
+            number = conf.entity_id_to_number('light.test')
-                assert number == '22'
+            assert number == '22'
-                assert handle.write.call_count == 1
+            assert json_saver.call_count == 1
 
-                number = conf.entity_id_to_number('light.test2')
+            number = conf.entity_id_to_number('light.test2')
-                assert number == '21'
+            assert number == '21'
-                assert handle.write.call_count == 1
+            assert json_saver.call_count == 1
 
-                entity_id = conf.number_to_entity_id('21')
+            entity_id = conf.number_to_entity_id('21')
-                assert entity_id == 'light.test2'
+            assert entity_id == 'light.test2'
 
 
 def test_config_google_home_entity_id_to_number_empty():
@@ -82,29 +80,29 @@ def test_config_google_home_entity_id_to_number_empty():
         'type': 'google_home'
     })
 
-    mop = mock_open(read_data='')
+    with patch('homeassistant.components.emulated_hue.load_json',
-    handle = mop()
+               return_value={}) as json_loader:
+        with patch('homeassistant.components.emulated_hue'
+                   '.save_json') as json_saver:
+            number = conf.entity_id_to_number('light.test')
+            assert number == '1'
+            assert json_saver.call_count == 1
+            assert json_loader.call_count == 1
 
-    with patch('homeassistant.util.json.open', mop, create=True):
+            assert json_saver.mock_calls[0][1][1] == {
-        with patch('homeassistant.util.json.os.open', return_value=0):
+                '1': 'light.test',
-            with patch('homeassistant.util.json.os.replace'):
+            }
-                number = conf.entity_id_to_number('light.test')
-                assert number == '1'
-                assert handle.write.call_count == 1
-                assert json.loads(handle.write.mock_calls[0][1][0]) == {
-                    '1': 'light.test',
-                }
 
-                number = conf.entity_id_to_number('light.test')
+            number = conf.entity_id_to_number('light.test')
-                assert number == '1'
+            assert number == '1'
-                assert handle.write.call_count == 1
+            assert json_saver.call_count == 1
 
-                number = conf.entity_id_to_number('light.test2')
+            number = conf.entity_id_to_number('light.test2')
-                assert number == '2'
+            assert number == '2'
-                assert handle.write.call_count == 2
+            assert json_saver.call_count == 2
 
-                entity_id = conf.number_to_entity_id('2')
+            entity_id = conf.number_to_entity_id('2')
-                assert entity_id == 'light.test2'
+            assert entity_id == 'light.test2'
 
 
 def test_config_alexa_entity_id_to_number():