Here are all terms you may encounter when working with the comparative testing. The concepts are arranged in the same order as you can see them in the Comparative testing tab.

Comparative testing

With this type of testing you compare how selected pages on a hostname will be served after config changes are applied with how they are delivered currently to real end users.

Results show the differences between the two behaviors, helping you predict what to expect after activating your configuration changes.

You can use it to compare how a hostname behaves on the Staging and the Production environments or on two Production environments. For example, to compare the behavior of config changes on a test hostname which doesn’t carry live traffic with the hostname that does.

Test definition

Test definition is a comparative testing unit. It is an ordered list of comparative test cases with settings common to all included test cases.

Test definition's settings include:

  • Hostname. It's the website you want to compare your configuration changes with.
  • Associated configuration. It's the configuration associated to a hostname for which the test definition was created.
  • IP versions. They're IP versions Test Center uses to make a request while running the test.

To run a test for test definition, it must have test cases associated. See also: Run a test for test definitions.

Test cases

A test case in the comparative testing specifies the page to be requested and the comparisons to be performed for the page and for all the embedded objects and redirect targets that are requested as a result of the page. It is a part of a test definition. See also: Create a test definition.

Test request

Test request is a constituent of a comparative test case. It is a combination of:

  • URL to test. It's the URL of the resource you want to test. It must be fully qualified and must contain the same hostname as that of the test definition that this test case belongs to. Currently the only supported method is GET.
  • Additional settings. It's the section where you add, modify, or modify request headers used by Test Center for running the comparative test.


Comparisons are constituents of a comparative test case. They enable you to select what you want Test Center to compare during the test run.

Comparison optionDescription
Response codeWhen selected, Test Center compares the returned HTTP response codes but only their numerical part, not the text that might accompany it. For example, 404 not 404 Not Found.
Response headersWhen selected, Test Center compares the presence and values of headers in the corresponding HTTP responses. By default, every header in the response is compared (except for a predefined list of headers).
Response headers to compare or ignoreWhen you provide an input, Test Center either compares or ignores the provided response headers.
CP codeWhen selected, Test Center compares CP codes used on specified environments. CP codes are content provider codes and are used by ​Akamai Technologies, Inc.​ to identify traffic for billing and reporting purposes.
Caching optionWhen selected, Test Center compares the caching option used on the specified environments.
Cache keyWhen selected, Test Center compares the cache keys used on the specified environments.
Note: If you use a private cache key or an origin response header to control the ability to cache content you may get unreliable results.
Metadata variablesWhen selected, Test Center compares the presence and values of every metadata variable used in the processing of the request.
This includes both user-defined and system variables. Hidden variables are only included if specific instructions are included in the hostname's delivery configuration. Sensitive variables are never included. By default, every variable set is compared when the test response is processed (except for a predefined list of variables).
Metadata variables to compare or ignoreWhen you provide an input, Test Center either compares or ignores the provided metadata variables.
Origin serverWhen selected, Test Center compares the origin servers used for specified sites and environments. The origin server is the physical location associated with an IP address that your content is retrieved from.
Note: The specific value compared will be incorrect if is used to override the hostname that edge servers reference in DNS.
Ignore embedded objectsWhen selected, Test Center performs the corresponding comparison for all requests triggered by the test case, ignoring requests for embedded objects and redirect targets. This only works if the objects are on the same hostname as the URL to test.