The macOS test tasks take a very long time to schedule (24 hours or more sometimes) and fail frequently due to test timeouts (see GODRIVER-2266). They only run on the waterfall so the main time we check them is when doing a release, when the macOS test tasks often haven't been scheduled yet for the released version. As a result, we get very little signal about test failures on macOS. Despite that, we still run macOS tests for every server version that the Go driver supports (v2.6+).

The only currently known internal project that needs to support EOL MongoDB server versions (see lifecycles for list) and may run on macOS is the mongo-tools project (v3.4+ to support Automation Agent).

We should stop running tests on macOS for EOL MongoDB server versions (currently v4.0 and earlier). The goal is to reduce the total amount of time a waterfall build takes and make it easier to focus on possible actual failures in the remaining macOS test tasks. We will still test the Go Driver against all supported server versions on Linux and Windows.

Definition of done:

• Remove macOS test tasks from the waterfall for any server version before v4.2.

Updated definition of done:

• Run macOS builds at most once per 24 hours using the "batchtime" config.