SDK provides a test-framework library to let operators run e2e tests

[hasbro17]

E2e tests are the most common way to test the reconciliation logic of an operator.
e.g: etcd-operator e2e, prometheus-operator e2e.
Currently users have to write their own e2e frameworks from scratch to test their SDK based operators.

The SDK can provide a test-framework library that would abstract out the common functionality needed by all e2e tests e.g setup/teardown (namespace, rbac, operator deployment) along with any other necessary testing utilities.
The SDK could also provide a standard way to run a users e2e tests e.g
operator-sdk test <path-to-e2e-tests> --kubeconfig=<kubeconfig>

Since the goal is to make it easier to write and run e2e tests for SDK based operators we'll need to determine how much value would such a test-framework actually provide.
This can be determined by considering:

• how much duplication and work can the test-framework abstractions actually reduce vs providing thin wrappers around existing utilities
• how simple is the workflow of using the test-framework vs writing your own framework from scratch and running go test ...

#377 provides a starting point for what such a framework could look like. We'll use that to iterate on the workflow and abstractions of the test-framework library.

[AlexNPavel]

Initial framework was implemented and merged with #377. Further work that will be added as separate PRs:

• Allow users to pass abritrary flags and arguments to go test: commands/.../test.go: allow passing of flags to go test #392
• Allow a user to add their own scheme to the dynamic client and get rid of some of the hacky CRClient stuff: Add AddToFrameworkScheme function for the test framework #393
• Have example workflow doc for the test framework: doc/test-framework: add test framework documentation #410

[hasbro17]

Closing this. We have the follow up work for packaging the e2e tests with the operator outlined in #435