getheader() in stubs should be case-insensitive

tests/integration/test_stubs.py

@@ -0,0 +1,26 @@
+import vcr
+import six.moves.http_client as httplib
+
+def _headers_are_case_insensitive():
+    conn = httplib.HTTPConnection('httpbin.org')
+    conn.request('GET', "/cookies/set?k1=v1")
+    r1 = conn.getresponse()
+    cookie_data1 = r1.getheader('set-cookie')
+    conn = httplib.HTTPConnection('httpbin.org')
+    conn.request('GET', "/cookies/set?k1=v1")
+    r2 = conn.getresponse()
+    cookie_data2 = r2.getheader('Set-Cookie')
+    return cookie_data1 == cookie_data2
+
+def test_case_insensitivity(tmpdir):
+    testfile = str(tmpdir.join('case_insensitivity.yml'))
+    # check if headers are case insensitive outside of vcrpy
+    outside = _headers_are_case_insensitive()
+    with vcr.use_cassette(testfile):
+        # check if headers are case insensitive inside of vcrpy
+        inside = _headers_are_case_insensitive()
+        # check if headers are case insensitive after vcrpy deserializes headers
+        inside2 = _headers_are_case_insensitive()
+
+    # behavior should be the same both inside and outside
+    assert outside == inside == inside2