And fix up the TestAutoUpdateDefaults integration tests as they
weren't testing reality: the DefaultAutoUpdate is supposed to only be
relevant on the first MapResponse in the stream, but the tests weren't
testing that. They were instead injecting a 2nd+ MapResponse.
This changes the test control server to add a hook to modify the first
map response, and then makes the test control when the node goes up
and down to make new map responses.
Also, the test now runs on macOS where the auto-update feature being
disabled would've previously t.Skipped the whole test.
Updates #11502
Change-Id: If2319bd1f71e108b57d79fe500b2acedbc76e1a6
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Brad Fitzpatrick
ac0b15356d