Bug 1586738 - Add Glean-iOS MetricsPingScheduler

[travis79]

This adds the MetricsPingScheduler to the iOS bindings.

[codecov-io]

Codecov Report

Merging #655 into master will increase coverage by 0.59%.
The diff coverage is 98.79%.

@@             Coverage Diff              @@
##             master     #655      +/-   ##
============================================
+ Coverage     74.69%   75.28%   +0.59%     
  Complexity      266      266              
============================================
  Files            96       97       +1     
  Lines          5936     6070     +134     
  Branches        730      730              
============================================
+ Hits           4434     4570     +136     
+ Misses          966      964       -2     
  Partials        536      536

Impacted Files	Coverage Δ	Complexity Δ
glean-core/ios/Glean/Utils/Utils.swift	94.38% <100%> (-0.25%)	0 <0> (ø)
...ore/ios/Glean/Scheduler/MetricsPingScheduler.swift	100% <100%> (ø)	0 <0> (?)
glean-core/ios/Glean/Glean.swift	92.65% <90.9%> (+1.12%)	0 <0> (ø)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 46ec798...8ea3514. Read the comment docs.

[badboy]

I need to give this another look, especially the tests.
For a first pass I found a few nitpicky things, but overall this looks like some very solid work already.

[travis79]

I need to give this another look, especially the tests.
For a first pass I found a few nitpicky things, but overall this looks like some very solid work already.

Please do check it carefully, the last two tests in the file were especially troublesome due to async hell.

[badboy]

Do we have any way to modify the clock used in the test to e.g. simulate the time hopping a bit better?
That way we could also test timezones changes more reliably.

[travis79]

Do we have any way to modify the clock used in the test to e.g. simulate the time hopping a bit better?
That way we could also test timezones changes more reliably.

We can change timezones but setting the date/time, even for tests seems to be possible only by scripting it from CLI. This SO post was the best I found from a quick search. Go Apple!

[Dexterp37]

Given @mdboom experience with the Android implementation, I'd recommend he takes at least one high level look at this.

[mdboom]

LGTM. Ideally, let's merge this before #649, and then have #649 add the reason codes for iOS.

[badboy]

static func - ... it does look weird.