Add code sample using generated mocks

Currently compute mocks are not used in any build or test, adding a sample would correct that and increase the breadth of documentation for the library.

Start by locating the generated compute mocks and existing code samples in the repository. Add a sample that exercises the mocks and is included in a build or test, then verify that the relevant build or test completes successfully.

索引モデルが issue の本文から書いたものです。