test: deterministic debounce test via synctest

[JamBalaya56562]

Summary

TestGenerateFromEvents drives the debounce logic through a real dockertest HTTP server and wall-clock time.Sleep calls, so the timing of debounce firings races the OS scheduler / timer resolution and the test fails nondeterministically (off-by-one or worse). It reproduces on main and is especially flaky on Windows. See #238.

This PR replaces it with TestNewDebounceChannel, which exercises newDebounceChannel directly inside a testing/synctest bubble. The fake clock makes the Min quiet-period coalescing and the Max cap fire at exact, reproducible virtual times, removing the real network and wall-clock dependence entirely.

Changes

• internal/generator/generator_test.go: replace TestGenerateFromEvents with TestNewDebounceChannel. Three deterministic subtests:
  • passthrough when Min == 0,
  • Min quiet-period coalescing (a burst collapses to one event, fired Min after the last event),
  • Max cap (output is forced out at Max while events keep arriving).

Notes

• No production code changes. newDebounceChannel already uses time.After, which synctest virtualizes.
• testing/synctest is stable as of Go 1.25 (go.mod declares go 1.25.5; the CI matrix tests Go 1.25 and 1.26). It is OS-independent, which removes the Windows timer-resolution flakiness at its root.
• Verified deterministic: go test -run TestNewDebounceChannel -count=200 passes.
• Trade-off: this focuses on the debounce timing (the logic that was actually flaky) rather than the full event → generate → output pipeline that the old test wrapped around a real Docker API server. If you'd prefer to keep an integration smoke test for that wiring (without timing assertions, so it stays deterministic), I'm happy to add one.

Fixes #238

[Copilot]

Pull request overview

This PR removes the flaky, wall-clock/network-driven debounce integration test (TestGenerateFromEvents) and replaces it with deterministic unit tests for newDebounceChannel using Go’s testing/synctest, addressing nondeterministic timing failures reported in #238.

Changes:

• Replaced TestGenerateFromEvents (dockertest server + real time.Sleep) with TestNewDebounceChannel built on testing/synctest.
• Added deterministic subtests covering: Min == 0 passthrough, Min quiet-period coalescing, and Max cap behavior.

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[buchdag]

@JamBalaya56562 same thing here, no issue or PR numbers in either PR titles or commit message.

[JamBalaya56562]

Done — dropped the issue number from the title and commit message, thanks!

[JamBalaya56562]

Separately: now that #748 (TestGetContainersNilStructs) is merged into main, updating this branch pulled that test in. I've added a commit restoring the imports it needs (encoding/json, fmt, net/http, strings, dockertest, dockerclient), which had been dropped along with TestGenerateFromEvents. Build/tests pass locally now.