More Service Status testing

[mattmoor]

@dprotaso enumerated a lot of good tests here

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I would suggest more granularity and test the scenarios below. Let me know if it's too pedantic. I'm suggesting this because there's no test for when a configuration fails and recovers. And there's some overlap testing the route failure flow in TestTypicalServiceFlow and TestRouteFailurePropagation

Each bullet point would be a scenario to test given the conditions when ...

service happy flow

when the service ready condition is unknown

• route ready condition becomes true
• configuration ready condition becomes true
• both route and configuration ready condition becomes true

failure propagation

when the service ready condition is true
and both route & configuration ready conditions are true

• route ready condition becomes false
• configuration ready condition becomes false

configuration recovery

when the service ready condition is false
and route ready condition is true
and configuration ready condition is false

• configuration ready condition becomes true

route recovery

when the service ready condition is false
and route ready condition is false
and configuration ready condition is true

• route ready condition becomes true

[dprotaso]

More test cases from here: #1222

unknown propagation

when the service ready condition is true
and both route & configuration ready conditions are true

• route ready condition becomes unknow
• configuration ready condition becomes unknown