Better test to protect against mutation.

modified:   .gitignore
	modified:   README.rst
	modified:   nested_lookup/lookup_api.py
	modified:   setup.py
	modified:   test_lookup_api.py

.gitignore

@@ -1,4 +1,5 @@
 __pycache__*
+.pytest_cache*
 *.pyc
 .coverage
 build/*

README.rst

@@ -1,7 +1,7 @@
 nested_lookup
 #############
 
-.. image:: https://img.shields.io/badge/pypi-0.2.11-green.svg
+.. image:: https://img.shields.io/badge/pypi-0.2.12-green.svg
   :target: https://pypi.python.org/pypi/nested-lookup
 
 Make working with JSON, YAML, and XML document responses fun again!
@@ -14,12 +14,14 @@ A document in this case is a a mixture of Python dictionary and list objects typ
   Returns a `list` of matching values.
 
 *nested_update:*
-  Given a document, find all occurences of the given key and update the value
+  Given a document, find all occurences of the given key and update the value.
-  By default, returns a copy of the document. To mutate the original one instead - please specify the `in_place=True` argument.
+  By default, returns a copy of the document.
+  To mutate the original specify the `in_place=True` argument.
 
 *nested_delete:*
   Given a document, find all occurrences of the given key and delete it.
-  Returns a copy of the document.
+  By default, returns a copy of the document.
+  To mutate the original specify the `in_place=True` argument.
 
 *get_all_keys:*
   Fetch all keys from a deeply nested dictionary.

nested_lookup/lookup_api.py

@@ -2,9 +2,10 @@ import copy
 from six import iteritems
 
 
-def nested_delete(document, key):
+def nested_delete(document, key, in_place=False):
-    duplicate = copy.deepcopy(document)
+    if not in_place:
-    return _nested_delete(document=duplicate, key=key)
+        document = copy.deepcopy(document)
+    return _nested_delete(document=document, key=key)
 
 
 def _nested_delete(document, key):

setup.py

@@ -20,8 +20,8 @@ with open('requirements.txt', 'r') as f:
 
 setup(
     name='nested-lookup',
-    version='0.2.11',
+    version='0.2.12',
-    description='lookup a key in a deeply nested document of dicts and lists',
+    description='Python functions for working with deeply nested documents (lists and dicts) ',
     keywords='nested document dictionary dict list lookup schema json xml yaml',
     long_description=open('README.rst').read(),
 
@@ -40,13 +40,8 @@ setup(
     classifiers=[
         # Specify the Python versions you support here. In particular, ensure
         # that you indicate whether you support Python 2, Python 3 or both.
-        'Programming Language :: Python :: 2',
         'Programming Language :: Python :: 2.6',
         'Programming Language :: Python :: 2.7',
-        'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.2',
-        'Programming Language :: Python :: 3.3',
-        'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',

test_lookup_api.py

@@ -103,18 +103,37 @@ class TestNestedUpdate(BaseLookUpApi):
             result, nested_update(self.sample_data1, 'build_version', 'Test1')
         )
 
-    def test_in_place(self):
+    def test_nested_update_in_place_false(self):
-        result = {
+        """nested_update should mutate and return a copy of the original document"""
-            "build_version": "Test1",
+        before_id = id(self.sample_data1)
-            "os_details": {
+        result = nested_update(self.sample_data1, 'build_version', 'Test2', in_place=False)
-                "product_version": '10.13.6',
+        after_id = id(result)
-                "build_version": 'Test1'
+        # the object ids should _not_ match.
-            },
+        self.assertNotEqual(before_id, after_id)
-            "name": 'Test',
+
-            "date": 'YYYY-MM-DD HH:MM:SS'
+    def test_nested_update_in_place_true(self):
-        }
+        """nested_update should mutate and return the original document"""
-        nested_update(self.sample_data1, 'build_version', 'Test1', in_place=True)
+        before_id = id(self.sample_data1)
-        self.assertEqual(result, self.sample_data1)
+        result = nested_update(self.sample_data1, 'build_version', 'Test2', in_place=True)
+        after_id = id(result)
+        # the object ids should match.
+        self.assertEqual(before_id, after_id)
+
+    def test_nested_delete_in_place_false(self):
+        """nested_delete should mutate and return a copy of the original document"""
+        before_id = id(self.sample_data1)
+        result = nested_delete(self.sample_data1, 'build_version', in_place=False)
+        after_id = id(result)
+        # the object ids should _not_ match.
+        self.assertNotEqual(before_id, after_id)
+
+    def test_nested_delete_in_place_true(self):
+        """nested_delete should mutate and return the original document"""
+        before_id = id(self.sample_data1)
+        result = nested_delete(self.sample_data1, 'build_version', in_place=True)
+        after_id = id(result)
+        # the object ids should match.
+        self.assertEqual(before_id, after_id)
 
     def test_sample_data2(self):
         result = {