fix(runner): report a response time value that does not fit a duration - #2655

Fixes #2663

Proposed changes

FilterOperator.Parse reads a bare number as seconds by retrying time.ParseDuration with an s appended, and that retry discarded its error:

value, err = time.ParseDuration(timeVal)
if err != nil && strings.Contains(err.Error(), "missing unit") {
    value, _ = time.ParseDuration(fmt.Sprintf("%ss", timeVal))
} else if err != nil {
    return operator, value, fmt.Errorf("invalid value provided for %s", f.flag)
}

A number that parses fine on its own but overflows once seconds are added takes the first branch, so value stays at zero and nothing is reported:

-mrt '>=10000000000'   ->  operator=">=" value=0s  err=<nil>

>= 0s is true for every response, so the flag silently matches every host instead of being rejected. The flags affected are -mrt, -match-response-time and -frt, -filter-response-time.

Larger values happen to be caught already, because they fail the first parse with "invalid duration" rather than "missing unit" and fall through to the error branch:

-mrt '>=99999999999999999999'  ->  err=invalid value provided for -mrt

So the gap is the range where the bare number is a valid float but the duration overflows, which starts a little above 9223372036 seconds.

Proof

Parse had no tests, so the new file covers the whole contract: each of the six operators, the bare-number path, space trimming, and the inputs that have to be rejected.

Against the current code only the overflow case fails:

--- FAIL: TestFilterOperatorParse/rejected/>=10000000000

The other fifteen subtests pass before and after, so the change is limited to the value that used to be swallowed.

go test ./runner/ passes, go vet is clean, and gofmt reports nothing.

Checklist

• Pull request is created against the dev branch
• All checks passed (lint, unit/integration/regression tests etc.) with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Summary by CodeRabbit

• Bug Fixes
  • Improved validation of duration filter values. Bare numeric values that exceed the supported duration range now return an invalid-value error instead of being treated as a zero-duration value. Valid formats, including bare numbers interpreted as seconds and values with surrounding whitespace, continue to work. This helps prevent invalid filters from silently producing misleading results.