Add script to check that the example responses in the swagger matches

the examples.

api/check_examples.py

@@ -0,0 +1,75 @@
+#! /usr/bin/env python
+
+import sys
+
+def import_error(module, package, debian, error):
+    sys.stderr.write((
+        "Error importing %(module)s: %(error)r\n"
+        "To install %(module)s run:\n"
+        "  pip install %(package)s\n"
+        "or on Debian run:\n"
+        "  sudo apt-get install python-%(debian)s\n"
+    ) % locals())
+    if __name__=='__main__':
+        sys.exit(1)
+
+try:
+    import jsonschema
+except ImportError as e:
+    import_error("jsonschema", "jsonschema", "jsonschema", e)
+    raise
+
+try:
+    import yaml
+except ImportError as e:
+    import_error("yaml", "PyYAML", "yaml", e)
+    raise
+
+import json
+import os
+
+def check_response(filepath, request, code, response):
+    try:
+        example = json.loads(
+            response.get('examples', {}).get('application/json', "null")
+        )
+    except Exception as e:
+        raise ValueError("Error parsing JSON example response for %r %r" % (
+            request, code
+        ), e)
+    schema = response.get('schema')
+    fileurl = "file://" + os.path.abspath(filepath)
+    if example and schema:
+        try:
+            print ("Checking schema for: %r %r %r" % (filepath, request, code))
+            # Setting the 'id' tells jsonschema where the file is so that it
+            # can correctly resolve relative $ref references in the schema
+            schema['id'] = fileurl
+            jsonschema.validate(example, schema)
+        except Exception as e:
+            raise ValueError("Error validating JSON schema for %r %r" %(
+                request, code
+            ), e)
+
+
+def check_swagger_file(filepath):
+    with open(filepath) as f:
+        swagger = yaml.load(f)
+
+    for path, path_api in swagger['paths'].items():
+        for method, request_api in path_api.items():
+            request = "%s %s" % (method.upper(), path)
+            try:
+                responses = request_api['responses']
+            except KeyError:
+                raise ValueError("No responses for %r" % (request,))
+            for code, response in responses.items():
+                check_response(filepath, request, code, response)
+
+
+if __name__=='__main__':
+    for path in sys.argv[1:]:
+        try:
+            check_swagger_file(path)
+        except Exception as e:
+            raise ValueError("Error checking file %r" % (path,), e)