for posterity, will want a command like this to test with:

./swarming.py run --swarming chromium-swarm-dev.appspot.com --print-status-updates --timeout 9000 --raw-cmd --task-name akeshet/qstest --priority 50 --dimension os Ubuntu-14.04 --dimension pool ChromeOSSkylab-suite --io-timeout 9000 --hard-timeout 9000 --expiration 1200 '--tags=skylab:run_suite' -- /usr/local/autotest/bin/run_suite_skylab --build nyan_blaze-paladin/R73-11357.0.0-rc2 --board nyan_blaze --suite_name dummy --pool quota-metered

This is fixed and tested in staging by https://chromium-review.googlesource.com/c/infra/infra/+/1374810/1 and its stack, just need to land those to mark this fixed.

The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra/+/bfa3946b05e3438ebf18e21f5b1e96e131293b6b

commit bfa3946b05e3438ebf18e21f5b1e96e131293b6b
Author: Aviv Keshet <akeshet@chromium.org>
Date: Fri Dec 14 18:27:25 2018

qscheduler: add ProvisionRequired logic to Assignment call

BUG= chromium:914187 
TEST=new unit test

Change-Id: I7743e73ac48784b19e470cf28554ea8df6855d71
Reviewed-on: https://chromium-review.googlesource.com/c/1374008
Reviewed-by: Allen Li <ayatane@chromium.org>
Commit-Queue: Aviv Keshet <akeshet@chromium.org>
Cr-Commit-Position: refs/heads/master@{#19565}
[modify] https://crrev.com/bfa3946b05e3438ebf18e21f5b1e96e131293b6b/go/src/infra/qscheduler/qslib/reconciler/reconciler.go
[modify] https://crrev.com/bfa3946b05e3438ebf18e21f5b1e96e131293b6b/go/src/infra/qscheduler/qslib/scheduler/task_test.go
[modify] https://crrev.com/bfa3946b05e3438ebf18e21f5b1e96e131293b6b/go/src/infra/qscheduler/qslib/scheduler/task.go
[modify] https://crrev.com/bfa3946b05e3438ebf18e21f5b1e96e131293b6b/go/src/infra/qscheduler/qslib/reconciler/reconciler_test.go
[modify] https://crrev.com/bfa3946b05e3438ebf18e21f5b1e96e131293b6b/go/src/infra/appengine/qscheduler-swarming/app/frontend/qscheduler.go
[modify] https://crrev.com/bfa3946b05e3438ebf18e21f5b1e96e131293b6b/go/src/infra/qscheduler/qslib/scheduler/scheduler.go

The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra/+/bb1f612cd2b43b2c31bfbf44486589e898ebe903

commit bb1f612cd2b43b2c31bfbf44486589e898ebe903
Author: Aviv Keshet <akeshet@chromium.org>
Date: Fri Dec 14 18:37:25 2018

qscheduler: correctly handle workers with multiple provisionable labels

Prior to this, provisional label matching was too strict, and would only
match workers if their provisionable labels were an exact match to those
of the request. In reality, we only need the worker's label set to
contain all of the task labels. Therefore, fix this logic.

BUG= chromium:914187 
TEST=unit test added, verified to fail prior to behavior fix

Change-Id: I63a1f127ec3a9ad7657f2e12346aded8fa89a19a
Reviewed-on: https://chromium-review.googlesource.com/c/1375130
Commit-Queue: Aviv Keshet <akeshet@chromium.org>
Reviewed-by: Allen Li <ayatane@chromium.org>
Cr-Commit-Position: refs/heads/master@{#19566}
[modify] https://crrev.com/bb1f612cd2b43b2c31bfbf44486589e898ebe903/go/src/infra/qscheduler/qslib/scheduler/scheduler_test.go
[modify] https://crrev.com/bb1f612cd2b43b2c31bfbf44486589e898ebe903/go/src/infra/qscheduler/qslib/scheduler/scheduler.go

The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra/+/dc821cfff07e0d723a01a3d7b3528119be0cc6dd

commit dc821cfff07e0d723a01a3d7b3528119be0cc6dd
Author: Aviv Keshet <akeshet@chromium.org>
Date: Fri Dec 14 23:22:27 2018

qscheduler: return correct slice number based on ProvisionRequred

BUG= chromium:914187 
TEST=None

Change-Id: I46089d44ff5d7b80eb13a944c55fe7146f86fc9e
Reviewed-on: https://chromium-review.googlesource.com/c/1374810
Reviewed-by: Allen Li <ayatane@chromium.org>
Commit-Queue: Aviv Keshet <akeshet@chromium.org>
Cr-Commit-Position: refs/heads/master@{#19578}
[modify] https://crrev.com/dc821cfff07e0d723a01a3d7b3528119be0cc6dd/go/src/infra/appengine/qscheduler-swarming/app/frontend/qscheduler.go