Convert dict headers and Webob headers into lowercase.

In the fold_headers function, if the headers behaves like a dict,
they were being retured unchanged. This would cause issues in the
later processing to extract the microversion header, which matches
on lower case strings.

Convert these headers to lowercase also provide a test case to
validate the header is being parsed correctly.

Change-Id: I8501c813d668c0a32905906e4ef3f8c6c6b12de2
Close-Bug:# 1606351

microversion_parse/__init__.py

@@ -90,8 +90,7 @@ def fold_headers(headers):
     # If it behaves like a dict, return it. Webob uses objects which
     # are not dicts, but behave like them.
     if hasattr(headers, 'keys'):
-        # TODO(cdent): canonicalize? (i.e. in lower())
-        return headers
+        return dict((k.lower(), v) for k, v in headers.items())
     header_dict = collections.defaultdict(list)
     for header, value in headers:
         header_dict[header.lower()].append(value.strip())

microversion_parse/tests/test_get_version.py

@@ -216,3 +216,12 @@ class TestGetHeaders(testtools.TestCase):
             headers, service_type='compute',
             legacy_headers=['x-openstack-nova-api-version'])
         self.assertEqual('2.0', version)
+
+    def test_capitalized_headers(self):
+        headers = {
+            'X-Openstack-Ironic-Api-Version': '123.456'
+        }
+        version = microversion_parse.get_version(
+            headers, service_type='ironic',
+            legacy_headers=['X-Openstack-Ironic-Api-Version'])
+        self.assertEqual('123.456', version)

microversion_parse/tests/test_webob.py

@@ -30,7 +30,8 @@ class TestWebobHeaders(testtools.TestCase):
 
         folded_headers = microversion_parse.fold_headers(headers)
         self.assertEqual(3, len(folded_headers))
-        self.assertEqual(set(headers.keys()), set(folded_headers.keys()))
+        self.assertEqual(set(['header-one', 'header-three', 'header-two']),
+                         set(folded_headers.keys()))
         self.assertEqual('gamma', folded_headers['header-three'])
 
     def test_simple_match(self):