tests: {successorssets} now always return a list, affecting json output

CORE-TEST-OUTPUT-UPDATE: f95b23283760
8 jobs for topic/default/alluring-cod in 6 minutes and 16 seconds (queued for 7 minutes and 21 seconds)
Status Job ID Name Coverage
  Test
passed #111112
checks-py2

00:01:13

passed #111113
checks-py3

00:01:00

passed #111118
doc

00:00:29

manual #111111
allowed to fail manual
pytype
failed #111114
tests-py2-cext

00:05:36

failed #111115
tests-py2-pure

00:05:12

failed #111116
tests-py3-cext

00:02:38

failed #111117
tests-py3-pure

00:02:48

 
Name Stage Failure
failed
tests-py2-cext Test
Skipped test-check-flake8.t: blacklisted
Skipped test-check-pyflakes.t: blacklisted
Skipped test-check-setup-manifest.t: blacklisted
Failed test-evolve-templates.t: output changed
# Ran 193 tests, 6 skipped, 1 failed.
python hash seed: 1040724689
Running after_script
Uploading artifacts for failed job
ERROR: Job failed: exit code 1
failed
tests-py2-pure Test
Skipped test-check-flake8.t: blacklisted
Skipped test-check-pyflakes.t: blacklisted
Skipped test-check-setup-manifest.t: blacklisted
Failed test-evolve-templates.t: output changed
# Ran 193 tests, 6 skipped, 1 failed.
python hash seed: 2316857443
Running after_script
Uploading artifacts for failed job
ERROR: Job failed: exit code 1
failed
tests-py3-pure Test
Skipped test-check-compat-strings.t: blacklisted
Skipped test-check-debian.t: blacklisted
Skipped test-check-flake8.t: blacklisted
Skipped test-check-pyflakes.t: blacklisted
Skipped test-check-setup-manifest.t: blacklisted
Failed test-evolve-templates.t: output changed
# Ran 193 tests, 6 skipped, 1 failed.
python hash seed: 4259913189
ERROR: Job failed: exit code 1
failed
tests-py3-cext Test
Skipped test-check-flake8.t: blacklisted
Skipped test-check-pyflakes.t: blacklisted
Skipped test-check-setup-manifest.t: blacklisted
Failed test-evolve-templates.t: output changed
# Ran 193 tests, 6 skipped, 1 failed.
python hash seed: 2377331647
Running after_script
Uploading artifacts for failed job
ERROR: Job failed: exit code 1