test: add simple integration test

[crandles]

• Extends pkg/daemon.Start and pkg/daemon/signaling with context.Context for cancellation
• Adds an integration top-level package and simple test calling equivalent to trickster binary
• Adds a new PR workflow job that runs the integration test

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I'm aiming to keep the tests high level; more specific backend logic should reside at the backend-package level. The integration tests are meant to test the variety of trickster layers all together.

This should allow for easier step-level debugging / bug report reproduction.

To Do:

• add prometheus backend tests
  • Not 100% sure of what this test will look like, but the goal is making sure it is reproducible / deterministic (and not flaky).
    • perhaps: Seed prometheus with some data, expect a certain result once queried through trickster.
    • perhaps: query prometheus direct & compare against trickster-proxied result?
• add method for running trickster via image (ad-hoc)
  • this will allow running new tests vs an older image

[coveralls]

Pull Request Test Coverage Report for Build 16105623242

Details

• 0 of 21 (0.0%) changed or added relevant lines in 4 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.005%) to 76.297%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
cmd/trickster/main.go	0	1	0.0%
pkg/daemon/setup/setup.go	0	2	0.0%
pkg/daemon/daemon.go	0	7	0.0%
pkg/daemon/signaling/signaling.go	0	11	0.0%

Totals
Change from base Build 15974287861:	0.005%
Covered Lines:	15325
Relevant Lines:	20086

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💛 - Coveralls