1472299 - Testing an expiring probe is problematic

Status: NEW

(Toolkit :: Telemetry, enhancement, P3)

Description

[Chris H-C :chutten]

We encourage people to write tests to ensure their probes don't break when the code changes around them, but we don't make it terribly easy.

One case is expiring probes. Services.telemetry.scalarSet('my.scalar', 55) will act the same whether 'my.scalar' is a scalar defined in this build or not, if 'my.scalar' is a scalar present in this build but is expired, and if 'my.scalar' is present and unexpired and whose value can then be expected to be present in a snapshot.

So, something like

Services.telemetry.isScalarDefined(scalarName);
Services.telemetry.isScalarExpired(scalarName);

or something like

let scalarInfo = Services.telemetry.getScalarInfo(scalarName);
if (scalarInfo && !scalarInfo.expired) {
  Assert.equal(scalarInfo.value, 55);
}

Comment 1

[Georg Fritzsche [:gfritzsche]]

Instead of this specific solution, could we just continue recording expired probes, but not send them?
That would not require any changes to test code at all.