From 0eda8ba482e12064b21238a513e502f0a032971e Mon Sep 17 00:00:00 2001
From: Aron Griffis <aron@arongriffis.com>
Date: Fri, 28 Aug 2015 07:25:03 -0400
Subject: [PATCH] Default path_transformer=None. Fixes #199

---
 tests/unit/test_cassettes.py |  7 +++++++
 tests/unit/test_vcr.py       | 22 ++++++++++++++++++++++
 vcr/cassette.py              |  2 +-
 vcr/config.py                |  4 ++--
 vcr/util.py                  |  5 +++--
 5 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/tests/unit/test_cassettes.py b/tests/unit/test_cassettes.py
index e1e9fb9..413b154 100644
--- a/tests/unit/test_cassettes.py
+++ b/tests/unit/test_cassettes.py
@@ -245,6 +245,13 @@ def test_path_transformer_with_context_manager():
         assert cassette._path == 'a'
 
 
+def test_path_transformer_None():
+    with Cassette.use(
+        path='a', path_transformer=None,
+    ) as cassette:
+        assert cassette._path == 'a'
+
+
 def test_func_path_generator():
     def generator(function):
         return os.path.join(os.path.dirname(inspect.getfile(function)),
diff --git a/tests/unit/test_vcr.py b/tests/unit/test_vcr.py
index cbdcde4..6cbf21b 100644
--- a/tests/unit/test_vcr.py
+++ b/tests/unit/test_vcr.py
@@ -98,6 +98,28 @@ def test_vcr_before_record_response_iterable():
             assert mock_filter.call_count == 1
 
 
+def test_vcr_path_transformer():
+    # Regression test for #199
+
+    # Prevent actually saving the cassette
+    with mock.patch('vcr.cassette.save_cassette'):
+
+        # Baseline: path should be unchanged
+        vcr = VCR()
+        with vcr.use_cassette('test') as cassette:
+            assert cassette._path == 'test'
+
+        # Regression test: path_transformer=None should do the same.
+        vcr = VCR(path_transformer=None)
+        with vcr.use_cassette('test') as cassette:
+            assert cassette._path == 'test'
+
+        # and it should still work with cassette_library_dir
+        vcr = VCR(cassette_library_dir='/foo')
+        with vcr.use_cassette('test') as cassette:
+            assert cassette._path == '/foo/test'
+
+
 @pytest.fixture
 def random_fixture():
     return 1
diff --git a/vcr/cassette.py b/vcr/cassette.py
index bc7410f..6dc6c40 100644
--- a/vcr/cassette.py
+++ b/vcr/cassette.py
@@ -75,7 +75,7 @@ class CassetteContextDecorator(object):
             lambda key, _: key in self._non_cassette_arguments,
             self._args_getter()
         )
-        if 'path_transformer' in other_kwargs:
+        if other_kwargs.get('path_transformer'):
             transformer = other_kwargs['path_transformer']
             cassette_kwargs['path'] = transformer(cassette_kwargs['path'])
         self.__finish = self._patch_generator(self.cls.load(**cassette_kwargs))
diff --git a/vcr/config.py b/vcr/config.py
index e2389db..99e4cf7 100644
--- a/vcr/config.py
+++ b/vcr/config.py
@@ -23,7 +23,7 @@ class VCR(object):
             return path
         return ensure
 
-    def __init__(self, path_transformer=lambda x: x, before_record_request=None,
+    def __init__(self, path_transformer=None, before_record_request=None,
                  custom_patches=(), filter_query_parameters=(), ignore_hosts=(),
                  record_mode="once", ignore_localhost=False, filter_headers=(),
                  before_record_response=None, filter_post_data_parameters=(),
@@ -108,7 +108,7 @@ class VCR(object):
         matcher_names = kwargs.get('match_on', self.match_on)
         path_transformer = kwargs.get(
             'path_transformer',
-            self.path_transformer or self.ensure_suffix('.yaml')
+            self.path_transformer
         )
         func_path_generator = kwargs.get(
             'func_path_generator',
diff --git a/vcr/util.py b/vcr/util.py
index 8c5bd94..b36ff75 100644
--- a/vcr/util.py
+++ b/vcr/util.py
@@ -81,8 +81,9 @@ def partition_dict(predicate, dictionary):
 def compose(*functions):
     def composed(incoming):
         res = incoming
-        for function in functions[::-1]:
-            res = function(res)
+        for function in reversed(functions):
+            if function:
+                res = function(res)
         return res
     return composed