feat(evaluator): port new test scenarios from PRs #341-345 into evaluator testkit

[aepfli]

Summary

Ports all new test scenarios introduced in PRs #341, #342, #343, and #345 into the evaluator/ testkit added by #344. These tests were not included in the original #344 branch.

Changes

evaluator/flags/testkit-flags.json — 11 new flags + 1 evaluator

Source	Additions
#340 (main)	fractional-hash-edge-flag
#341	semver-v-prefix-flag, semver-partial-version-flag, semver-build-metadata-flag
#342	semver-invalid-version-flag, semver-invalid-operator-flag, fractional-null-bucket-key-flag
#343	nested-ref-targeted-flag + is_privileged evaluator
#345	fractional-nested-if-flag, fractional-nested-var-flag

evaluator/gherkin/fractional.feature

• @fractional-v2 — hash edge cases (boundary values for MurmurHash3 precision)
• @fractional-nested — nested if and var expressions as bucket variant names
• @operator-errors — null bucket key falls back to default variant

evaluator/gherkin/semver.feature

• @semver-edge-cases — v-prefix handling, partial version, build metadata ignored
• @operator-errors — unparseable version and unknown operator both return null → fallback

evaluator/gherkin/evaluator-refs.feature

• @evaluator-ref-edge-cases — nested $ref resolution (is_privileged → is_ballmer)

Related

• feat(semver): add edge case scenarios for v-prefix, partial versions, and build metadata #341 — semver edge cases
• feat(operators): add error return scenarios for custom operator null fallback #342 — operator error null returns
• feat(evaluators): add nested $ref resolution scenarios #343 — nested evaluator ref resolution
• feat: add evaluator testkit gherkin features and flag configuration #344 — evaluator testkit (base PR this builds on)
• feat(fractional): add nested fractional expression gherkin scenarios #345 — nested fractional expressions

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request integrates a substantial collection of new test scenarios into the evaluator testkit, enhancing the robustness and reliability of the flag evaluation system. By covering a wider array of conditions, including complex operators, error handling, and edge cases, these changes ensure that the evaluator behaves as expected across diverse configurations and inputs. This expansion of test coverage is crucial for maintaining the quality and predictability of feature flag evaluations.

Highlights

• New Test Scenarios Ported: Incorporated a comprehensive suite of new test scenarios from PRs feat(semver): add edge case scenarios for v-prefix, partial versions, and build metadata #341, feat(operators): add error return scenarios for custom operator null fallback #342, feat(evaluators): add nested $ref resolution scenarios #343, and feat(fractional): add nested fractional expression gherkin scenarios #345 into the evaluator/ testkit, significantly expanding test coverage.
• Expanded Flag Definitions: Added 11 new flag definitions and one new evaluator (is_privileged) to evaluator/flags/testkit-flags.json to support the new test cases.
• New Gherkin Feature Files: Introduced multiple new Gherkin feature files covering various evaluation aspects, including error handling, basic evaluation, evaluator references, fractional operator behavior, metadata, no-default-variant handling, semantic versioning, string operators, targeting, and zero-value resolution.
• Fractional Operator Enhancements: Updated existing fractional operator tests and added new scenarios for hash edge cases and nested expressions within the fractional operator, ensuring robust behavior for complex bucketing logic.

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[gemini-code-assist]

Code Review

This pull request successfully ports new test scenarios from several previous PRs into the evaluator testkit. The new flag definitions in evaluator/flags/testkit-flags.json are well-structured and consistent with existing patterns. The accompanying Gherkin feature files (evaluator/gherkin/*.feature) clearly define the new test cases for error handling, basic evaluation, evaluator references, fractional operators, metadata, no-default variants, semantic versioning, string comparisons, targeting, and zero values. The updates to flags/custom-ops.json and gherkin/targeting.feature also integrate smoothly, enhancing the test coverage for fractional operator edge cases and versioning. Overall, the changes significantly improve the robustness of the evaluator test suite.

[aepfli]

Closing as superseded. The evaluator testkit backfill has been distributed into the individual feature branches:

• PR feat(semver): add edge case scenarios for v-prefix, partial versions, and build metadata #341 (test/semver-edge-cases) now includes the semver edge-case evaluator scenarios and flags
• PR feat(operators): add error return scenarios for custom operator null fallback #342 (test/operator-error-returns) now includes the operator-error evaluator scenarios and flags
• PR feat(evaluators): add nested $ref resolution scenarios #343 (test/evaluator-ref-edge-cases) now includes the nested $ref evaluator scenarios and flags
• The nested fractional evaluator counterparts (from feat(fractional): add nested fractional expression gherkin scenarios #345) are being added in a dedicated follow-up PR

This approach keeps each feature self-contained and avoids a single large backfill PR that becomes hard to review and prone to merge conflicts.