handle duplicate JSON keys only when possible

ext_tests.py

@@ -35,7 +35,6 @@
 https://github.com/json-patch/json-patch-tests """
 
 from functools import partial
-import json
 import doctest
 import unittest
 import jsonpatch
@@ -94,7 +93,8 @@ def get_suite(filenames):
 
     for testfile in filenames:
         with open(testfile) as f:
-            tests = json.load(f, object_pairs_hook=jsonpatch.multidict)
+            # we use the (potentially) patched version of json.load here
+            tests = jsonpatch.json.load(f)
             cls = make_test_case(tests)
             suite.addTest(unittest.makeSuite(cls))
 

jsonpatch.py

@@ -85,6 +85,27 @@ def multidict(ordered_pairs):
     return dict(d)
 
 
+def get_loadjson():
+    """ adds the object_pairs_hook parameter to json.load when possible
+
+    The "object_pairs_hook" parameter is used to handle duplicate keys when
+    loading a JSON object. This parameter does not exist in Python 2.6. This
+    methods returns an unmodified json.load for Python 2.6 and a partial
+    function with object_pairs_hook set to multidict for Python versions that
+    support the parameter. """
+
+    import inspect
+    import functools
+
+    argspec = inspect.getargspec(json.load)
+    if 'object_pairs_hook' not in argspec.args:
+        return json.load
+
+    return functools.partial(json.load, object_pairs_hook=multidict)
+
+json.load = get_loadjson()
+
+
 def apply_patch(doc, patch, in_place=False):
     """Apply list of patches to specified json document.
 
@@ -231,7 +252,7 @@ class JsonPatch(object):
 
         :return: :class:`JsonPatch` instance.
         """
-        patch = json.loads(patch_str, object_pairs_hook=multidict)
+        patch = json.loads(patch_str)
         return cls(patch)
 
     @classmethod