Objective: make the tests more robust and reduce random failures.
Preliminary refactoring:
- Accept testing.TB in testenv helpers. This is needed to
use `require.EventuallyWithT` in socket activation tests.
- Rename parameters for clarity
Tests refactoring:
- use t.Cleanup instead of defer where appropriate
- create file handlers in test routine instead of go routines
- remove unnecessary var declaration
- increased wait time to 30 seconds.
- allow running socket activation test on Darwin
Ref:
- #3283
- #3313
- #3318
- upgrade to golangci-lint 2.6.1
- updates for gosec
- updates for govet
- updates for perfsprint
- updates modernize
Leaves out modernize:omitempty due to conflicts with tests
- enable `forcetypeassert` linter in non-test files
- add `//nolint` annotations
- add `testutil.EnsureType` helper for type assertions
- enable `forcetypeassert` linter in test files
* use uint8 for clarity
* unexport writeContentAsyncAndVerify
* fix typo in test function name
* remove commented interface functions
* use atomic.Int32
* cleanups in socket server activation test
* leverage stdlib's maps and slices packages
replace uses of `golang.org/x/exp/maps`
* nit: leverage `maps.Values`
