Create additional checks for Cache-Control header (#5) (MDQ-161)

md-query.robot

@@ -51,7 +51,27 @@ Variables  variables.py
   ${resp}=    Conditional Get Entity    baseUrl=${BASE_URL}  identifier=${ENTITY_ID_ENCODED}  etag=${etag}
   Should Be Equal As Strings    ${resp.status_code}  304  msg=SHOULD return HTTP status code 304
 
-# 4.2 Content Caching
+4.2 Content Caching
+  [Tags]  optional
+  # "Responders SHOULD include cache control information with successful
+  # (200 status code) responses, assuming the responder knows when
+  # retrieved metadata is meant to expire."
+  ${resp}=    Get Entity    baseUrl=${BASE_URL}  identifier=${ENTITY_ID_ENCODED}
+  Should Be Equal As Strings    ${resp.status_code}  200
+  Dictionary Should Contain Key    ${resp.headers}  cache-control  msg=SHOULD return Cache-Control header with Success response
+  # "When cache controls are used only the 'max-age' directive SHOULD be used."
+  ${directive}=    Get From Dictionary    ${resp.headers}  cache-control
+  Should Start With    ${directive}    max-age=  msg=Only the 'max-age' directive SHOULD be used
+
+  # "The responder SHOULD also include cache control information with 404 Not
+  # Found responses. This allows the requester to create and maintain a
+  # negative-response cache."
+  ${resp}=    Get Entity    baseUrl=${BASE_URL}  identifier=foo
+  Should Be Equal As Strings    ${resp.status_code}  404
+  Dictionary Should Contain Key    ${resp.headers}  cache-control  msg=SHOULD return Cache-Control header with Not Found response
+  # "When cache controls are used only the 'max-age' directive SHOULD be used."
+  ${directive}=    Get From Dictionary    ${resp.headers}  cache-control
+  Should Start With    ${directive}    max-age=  msg=Only the 'max-age' directive SHOULD be used
 
 4.3 Content Compression
   ${resp}=    Get Entity With Gzip    baseUrl=${BASE_URL}  identifier=${ENTITY_ID_ENCODED}