We introduce a LazyCluster abstraction (instead of copy-pasted logic)
that makes clusters to be created only if there are runnable tests
in need for the infrastructure.
This CL tries to connect 2 objectives:
- Examples should be close (the same package) to the original code,
such that they can participate in documentation.
- Examples should be runnable - such that they are not getting out of
sync with underlying API/implementation.
In case of etcd-client, the examples are assuming running 'integration'
style, i.e. thay do connect to fully functional etcd-server.
That would lead to a cyclic dependencies between modules:
- server depends on client (as client need to be lightweight)
- client (for test purposes) depend on server.
Go modules does not allow to distingush testing dependency from
prod-code dependency.
Thus to meet the objective:
- The examples are getting executed within testing/integration packages against real etcd
- The examples are symlinked to 'unit' tests, such that they included in documentation.
- Long-term the unit examples should get rewritten to use 'mocks' instead of real integration tests.
