[Discover] test suite improvements

[drewdaemon]

This is a place to remember improvement ideas we have as we complete the Scout test migration.

Eventually, we will turn these into follow-up tasks to improve the quality of our test suite.

[drewdaemon]

In some cases, the tests use the UI to create fixtures. This is much slower than loading pre-built fixtures via kbnarchiver. We should do that instead!

• src/platform/plugins/shared/discover/test/scout/ui/parallel_tests/core/dataview_without_timefield.spec.ts builds a couple of saved searches using the UI (coming in [discover-scout] migrate two dataview related e2e tests #271998)

[akowalska622]

• src/platform/plugins/shared/discover/test/scout/ui/parallel_tests/core/new_tab.spec.ts creates an ad hoc data view through the UI as part of the test setup (new tab + createDataViewFromSearchBar with prefilled name. This is another good fixture candidate. Original code introduced in: [discover-scout] Tabs FTR tests to Scout migration part 1

[MiloszRadzynski]

• src/platform/plugins/shared/discover/test/scout/ui/parallel_tests/core/data_grid/data_grid_context_dashboard.spec.ts (Line 60) creates a new dashboard, adds the saved session as Discover embeddable and saves the dashboard. Introduced in [discover-scout] Migrate group2_data_grid FTR tests

[MiloszRadzynski]

• src/platform/plugins/shared/discover/test/scout/ui/parallel_tests/core/data_grid/data_grid_sample_size_saved_search_dashboard.spec.ts (Line 147), creates a new dashboard, adds the saved session as Discover embeddable and saves the dashboard. Introduced in [discover-scout] Migrate group2_data_grid FTR tests

[drewdaemon]

In some cases, EUI CSS selectors are being used. We can consider replacing these with data-test-subj attributes for greater durability

• e.g. [discover-scout] migrate two dataview related e2e tests #271998 (comment)

[drewdaemon]

The date_nanos type has many e2e tests in Discover. date_nanos was once a very special case with different client-side code paths. At this point, the special handling appears to boil down to sending the right formatting information to Elasticsearch. So, the e2e tests may be overkill.

One example: https://github.com/elastic/kibana/pull/272459/changes#diff-150d491237e4556bac5fb6094897153566a8c54d98638320f53ff611f3852bf2

[akowalska622]

Coverage gaps (eg. no ES|QL tests, edge cases not covered etc) to fill after migration

[akowalska622]

No ES|QL coverage in src/platform/plugins/shared/discover/test/scout/ui/parallel_tests/core/inspector_stats.spec.ts

Source: #279095 (comment)

[drewdaemon]

Page object/fixture improvements

[drewdaemon]

Add waitForHitCountToBe method to make hit count checks more stable. Ref: #281508 (comment)

[drewdaemon]

The functional test that preceded src/platform/plugins/shared/discover/test/scout/core/ui/parallel_tests/request_counts_data_view.spec.ts and src/platform/plugins/shared/discover/test/scout/core/ui/parallel_tests/request_counts_data_view.spec.ts passed on Serverless. The Scout tests don't. We should find out why.

[momovdg]

From the PR, this test src/platform/plugins/shared/discover/test/scout/core/ui/parallel_tests/adhoc_data_views.spec.ts ran on serverless as well, but was flaky. Reverted to stateful so we can decide if we want to port it at some point even though it increases the runtime.

[AlexGPlay]

run the flaky test runner in this PR and got src/platform/plugins/shared/discover/test/scout/esql/ui/parallel_tests/lookup_index_editor_existing_index.spec.ts failing multiple times

[AlexGPlay]

Improve src/platform/plugins/shared/discover/test/scout/esql/ui/parallel_tests/visualization_persistence.spec.ts "persists a Lens flyout shape and closes the flyout on revert" as it is a slow test that may flake if the test servers are slow