Fix folded header checks for WebOb

WebOb uses a Mapping class for headers which behaves like a dict
but does not inherit from dict, so the isinstance check in
fold_headers was not working as expected. This is now replaced
with a check for dict-like behaviors. It's a bit of a tossup
between doing a hasattr and simply trying to access a key. I chose
the former for readability and because we don't actually want to
do anything with the value we would retrieve were access by a key
legit.

Tests are added to specfically cover the use of a
webob.headers.EnvironHeaders object, which is what headers in
Nova and Nova derivations look like.

Change-Id: I31de49bcfd8822c53d3293b106de96138eaf4464

microversion_parse/__init__.py

@@ -89,7 +89,9 @@ def check_standard_header(headers, service_type):
 
 def fold_headers(headers):
     """Turn a list of headers into a folded dict."""
-    if isinstance(headers, dict):
+    # 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
     header_dict = collections.defaultdict(list)

microversion_parse/tests/test_webob.py

@@ -0,0 +1,79 @@
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import testtools
+
+from webob import headers as wb_headers
+
+import microversion_parse
+
+
+class TestWebobHeaders(testtools.TestCase):
+    """Webob uses a dict-like header which is not actually a dict."""
+
+    def test_simple_headers(self):
+        headers = wb_headers.EnvironHeaders({
+            'HTTP_HEADER_ONE': 'alpha',
+            'HTTP_HEADER_TWO': 'beta',
+            'HTTP_HEADER_THREE': 'gamma',
+        })
+
+        folded_headers = microversion_parse.fold_headers(headers)
+        self.assertEqual(3, len(folded_headers))
+        self.assertEqual(set(headers.keys()), set(folded_headers.keys()))
+        self.assertEqual('gamma', folded_headers['header-three'])
+
+    def test_simple_match(self):
+        headers = wb_headers.EnvironHeaders({
+            'HTTP_HEADER_ONE': 'alpha',
+            'HTTP_OPENSTACK_API_VERSION': 'compute 2.1',
+            'HTTP_HEADER_TWO': 'beta',
+        })
+        version = microversion_parse.check_standard_header(headers, 'compute')
+        self.assertEqual('2.1', version)
+
+    def test_match_multiple_services(self):
+        headers = wb_headers.EnvironHeaders({
+            'HTTP_HEADER_ONE': 'alpha',
+            'HTTP_OPENSTACK_API_VERSION':
+            'network 5.9 ,compute 2.1,telemetry 7.8',
+            'HTTP_HEADER_TWO': 'beta',
+        })
+        version = microversion_parse.check_standard_header(
+            headers, 'compute')
+        self.assertEqual('2.1', version)
+        version = microversion_parse.check_standard_header(
+            headers, 'telemetry')
+        self.assertEqual('7.8', version)
+
+    def test_legacy_headers_straight(self):
+        headers = wb_headers.EnvironHeaders({
+            'HTTP_HEADER_ONE': 'alpha',
+            'HTTP_X_OPENSTACK_NOVA_API_VERSION': ' 2.1 ',
+            'HTTP_HEADER_TWO': 'beta',
+        })
+        version = microversion_parse.get_version(
+            headers, service_type='compute',
+            legacy_headers=['x-openstack-nova-api-version'])
+        self.assertEqual('2.1', version)
+
+    def test_legacy_headers_folded(self):
+        headers = wb_headers.EnvironHeaders({
+            'HTTP_HEADER_ONE': 'alpha',
+            'HTTP_X_OPENSTACK_NOVA_API_VERSION': ' 2.1, 9.2 ',
+            'HTTP_HEADER_TWO': 'beta',
+        })
+        version = microversion_parse.get_version(
+            headers, service_type='compute',
+            legacy_headers=['x-openstack-nova-api-version'])
+        self.assertEqual('9.2', version)

test-requirements.txt

@@ -4,3 +4,4 @@ sphinx!=1.2.0,!=1.3b1,<1.3,>=1.1.2 # BSD
 oslosphinx!=3.4.0,>=2.5.0 # Apache-2.0
 testrepository>=0.0.18 # Apache-2.0/BSD
 testtools>=1.4.0 # MIT
+WebOb>=1.2.3 # MIT