From 1d8326f3a0a266b13509949d0396f338ea2886c1 Mon Sep 17 00:00:00 2001
From: Lukasz Balcerzak <lukaszbalcerzak@gmail.com>
Date: Wed, 7 Oct 2020 13:32:24 +0200
Subject: [PATCH] Refactor + allow to extend default ignore list

---
 README.rst              | 11 +++++++++--
 freezegun/api.py        |  4 ++--
 freezegun/config.py     | 24 ++++++++++++++++++-----
 tests/test_configure.py | 42 ++++++++++++++++++++++++++++++++++++++---
 4 files changed, 69 insertions(+), 12 deletions(-)

diff --git a/README.rst b/README.rst
index c7bd7ee3..afc5a498 100644
--- a/README.rst
+++ b/README.rst
@@ -305,7 +305,14 @@ It's possible to set your own default ignore list:
 
     import freezegun
 
-    freezegun.configure(default_ignore=['threading', 'tensorflow'])
+    freezegun.configure(default_ignore_list=['threading', 'tensorflow'])
 
 
-Please note this will override default ignore list.
+Please note this will override default ignore list. If you want to extend existing defaults
+please use:
+
+.. code-block:: python
+
+    import freezegun
+
+    freezegun.configure(extend_ignore_list=['tensorflow'])
diff --git a/freezegun/api.py b/freezegun/api.py
index 58aa825e..ac4c7948 100644
--- a/freezegun/api.py
+++ b/freezegun/api.py
@@ -810,8 +810,8 @@ def freeze_time(time_to_freeze=None, tz_offset=0, ignore=None, tick=False, as_ar
     if ignore is None:
         ignore = []
     ignore = ignore[:]
-    if config.settings.default_ignore:
-        ignore.extend(config.settings.default_ignore)
+    if config.settings.default_ignore_list:
+        ignore.extend(config.settings.default_ignore_list)
 
     return _freeze_time(
         time_to_freeze_str=time_to_freeze,
diff --git a/freezegun/config.py b/freezegun/config.py
index 33b62279..4a735b6d 100644
--- a/freezegun/config.py
+++ b/freezegun/config.py
@@ -1,6 +1,6 @@
 
 
-DEFAULT_IGNORE = [
+DEFAULT_IGNORE_LIST = [
     'nose.plugins',
     'six.moves',
     'django.utils.six.moves',
@@ -15,12 +15,26 @@
 
 
 class Settings:
-    def __init__(self, default_ignore=None):
-        self.default_ignore = default_ignore or DEFAULT_IGNORE[:]
+    def __init__(self, default_ignore_list=None):
+        self.default_ignore_list = default_ignore_list or DEFAULT_IGNORE_LIST[:]
 
 
 settings = Settings()
 
 
-def configure(default_ignore=None):
-    settings.default_ignore = default_ignore
+class ConfigurationError(Exception):
+    pass
+
+
+def configure(default_ignore_list=None, extend_ignore_list=None):
+    if default_ignore_list is not None and extend_ignore_list is not None:
+        raise ConfigurationError("Either default_ignore_list or extend_ignore_list might be given, not both")
+    if default_ignore_list:
+        settings.default_ignore_list = default_ignore_list
+    if extend_ignore_list:
+        settings.default_ignore_list = [*settings.default_ignore_list, *extend_ignore_list]
+
+
+def reset_config():
+    global settings
+    settings = Settings()
diff --git a/tests/test_configure.py b/tests/test_configure.py
index 3e994345..f787fb1b 100644
--- a/tests/test_configure.py
+++ b/tests/test_configure.py
@@ -1,20 +1,56 @@
 from unittest import mock
 import freezegun
+import freezegun.config
+
+
+def setup_function():
+    freezegun.config.reset_config()
 
 
 def teardown_function():
-    freezegun.configure(default_ignore=None)
+    freezegun.config.reset_config()
+
+
+def test_default_ignore_list_is_overridden():
+    freezegun.configure(default_ignore_list=['threading', 'tensorflow'])
+
+    with mock.patch("freezegun.api._freeze_time.__init__", return_value=None) as _freeze_time_init_mock:
+
+        freezegun.freeze_time("2020-10-06")
+
+        expected_ignore_list = [
+            'threading',
+            'tensorflow',
+        ]
 
+        _freeze_time_init_mock.assert_called_once_with(
+            time_to_freeze_str="2020-10-06",
+            tz_offset=0,
+            ignore=expected_ignore_list,
+            tick=False,
+            as_arg=False,
+            as_kwarg='',
+            auto_tick_seconds=0,
+        )
 
-def test_default_ignore_is_overridden():
-    freezegun.configure(default_ignore=['threading', 'tensorflow'])
+def test_extend_default_ignore_list():
+    freezegun.configure(extend_ignore_list=['tensorflow'])
 
     with mock.patch("freezegun.api._freeze_time.__init__", return_value=None) as _freeze_time_init_mock:
 
         freezegun.freeze_time("2020-10-06")
 
         expected_ignore_list = [
+            'nose.plugins',
+            'six.moves',
+            'django.utils.six.moves',
+            'google.gax',
             'threading',
+            'Queue',
+            'selenium',
+            '_pytest.terminal.',
+            '_pytest.runner.',
+            'gi',
             'tensorflow',
         ]