These packages contain code that can help you test against the GCP Client Libraries for Go (https://github.com/GoogleCloudPlatform/google-cloud-go). We do not recommend using mocks for most testing. Please read https://testing.googleblog.com/2013/05/testing-on-toilet-dont-overuse-mocks.html. Note: These packages are in alpha. Some backwards-incompatible changes may occur. All interfaces in this package include an embedToIncludeNewMethods method. This is intentionally unexported so that any implementor of the interface must embed the interface in their implementation. Embedding the interface in an implementation has the effect that any future methods added to the interface will not cause compile-time errors (the implementation does not implement the newly-added method), since embedded interfaces provide a default method for unimplemented methods. See Example (RecordBuckets) for an example of how to implement interfaces (including embedding the interface).