Enzyme to React Testing Library Migration

Goal

Migrate enzyme tests to @testing-library/react as a 1:1 port — preserve existing test intent without refactoring toward integration-style testing or removing mocks.

Core principles

• Preserve test intent. Do not rewrite test logic or remove mocks. Add mocks where enzyme's shallow rendering previously hid missing providers/contexts.
• Cut dead tests. Enzyme tests component trees, not DOM. Tests that assert on elements never actually rendered in the DOM should be removed with a comment explaining why.
• No new data-test-subj for snapshots. Use container.children[0] for root-element snapshots instead of adding a test locator just for snapshotting.

Migration workflow

1. Replace enzyme imports with RTL imports.
2. Replace shallow() / mount() with render().
3. Migrate selectors and assertions.
4. Update or delete snapshots (--updateSnapshot).
5. Run the test and fix any missing mocks/providers that enzyme's shallow rendering was hiding.