NPM update @web/test-runner causes tests to fail

[blackfalcon]

General Support Request

When updating @web/test-runner 0.15.3 ❯ 0.18.0

 Non-Semver Versions less than 1.0.0, caution.
❯◯ @web/dev-server devDep   0.1.38  ❯  0.4.1   https://github.com/modernweb-dev/web/tree/master/packages/dev-server
 ◯ @web/test-runner devDep  0.15.3  ❯  0.18.0  https://github.com/modernweb-dev/web/tree/master/packages/test-runner

See the following error in the stack trace

test/auro-datepicker.test.js:

 🚧 Browser logs:
      Lit is in dev mode. Not recommended for production! See https://lit.dev/msg/dev-mode for more information.
      Multiple versions of Lit loaded. Loading multiple versions is not recommended. See https://lit.dev/msg/multiple-versions for more information.
      Element auro-dropdown scheduled an update (generally because a property was set) after an update completed, causing a new update to be scheduled. This is inefficient and should be avoided unless the next update can only be scheduled as a side effect of the previous update. See https://lit.dev/msg/change-in-update for more information.
      Element auro-input scheduled an update (generally because a property was set) after an update completed, causing a new update to be scheduled. This is inefficient and should be avoided unless the next update can only be scheduled as a side effect of the previous update. See https://lit.dev/msg/change-in-update for more information.
      Element auro-calendar scheduled an update (generally because a property was set) after an update completed, causing a new update to be scheduled. This is inefficient and should be avoided unless the next update can only be scheduled as a side effect of the previous update. See https://lit.dev/msg/change-in-update for more information.
      Element auro-calendar-month scheduled an update (generally because a property was set) after an update completed, causing a new update to be scheduled. This is inefficient and should be avoided unless the next update can only be scheduled as a side effect of the previous update. See https://lit.dev/msg/change-in-update for more information.
      Element auro-calendar-cell scheduled an update (generally because a property was set) after an update completed, causing a new update to be scheduled. This is inefficient and should be avoided unless the next update can only be scheduled as a side effect of the previous update. See https://lit.dev/msg/change-in-update for more information.
      Element auro-datepicker scheduled an update (generally because a property was set) after an update completed, causing a new update to be scheduled. This is inefficient and should be avoided unless the next update can only be scheduled as a side effect of the previous update. See https://lit.dev/msg/change-in-update for more information.

 ❌ auro-datepicker > handles the required state being set
      AssertionError: expected null to equal 'valueMissing'
        at n.<anonymous> (test/auro-datepicker.test.js:80:53)

Chrome: |██████████████████████████████| 1/1 test files | 36 passed, 1 failed

Code coverage: 77.27 %
View full coverage report at coverage/lcov-report/index.html

Finished running tests in 13s with 1 failed tests.

ERROR: "test" exited with 1.

This is also curious

Multiple versions of Lit loaded.

Noticed that these dependencies were not updated with the last feature release.

"@web/dev-server": "^0.1.38",
"@web/test-runner": "^0.15.3",

Possible Solution

Review differences between versions 0.15.3 ❯ 0.18.0 and update tests as needed.

Additional context

Was able to determine that there is an issue starting from version 0.16.1

test/auro-datepicker.test.js:

 ❌ auro-datepicker > handles the required state being set
      AssertionError: expected null to equal 'valueMissing'
        at n.<anonymous> (test/auro-datepicker.test.js:80:53)

There doesn't seem to be any issues with @web/dev-server but not fully determined.

Exit criteria

This issue can be closed once all @web dependencies have been updated to the most recent versions and there are no test runner issues.