Add mParticle template targeting to tests

[zaraGNM]

What does this change?

This PR Introduces support for mParticle template personalisation in both Banners and epics. It allows for substitution of user attributes from mParticle profiles into banner and epic content, based on templates defined in A/B test configurations.

The changes:

• Added support for mParticleTemplates in both banner and epic A/B test schemas (bannerTestFromToolSchema and epicTestFromToolSchema) and their corresponding props, allowing tests to specify which mParticle user attributes should be substituted into content.
• Implemented helper functions in mParticleTemplates.ts to check for required user attributes (matchesMParticleTemplates) and to substitute attribute values into banner and epic content (substituteMParticleTemplate, substituteMParticleTemplateInBannerVariant, substituteMParticleTemplateInEpicVariant).
• Modified banner and epic routers to perform template substitution at request time, injecting personalised content into the response if the user profile contains the necessary attributes.
• Added unit tests for the template substitution logic, covering edge cases such as missing attributes and multiple substitutions.
  Added unit tests for template matching and substitution, covering missing profiles, missing attributes, multiple substitutions, and regular tests that do not require mParticle attributes.

Why are we doing this PR?

Currently, Banner and Epic tests can't use mParticle attributes to personalise their content. Adding mParticle templates means we can personalise content using a user's mParticle attributes, such as first name or previous contribution amount.

How to test?

Tested locally using a stubbed mParticle profile.

• Add a test mParticle profile containing the required user attribute.
• Run SDC with MPARTICLE_STUB_PROFILE=true so it uses the test profile instead of the mParticle API.
• Run dotcom rendering against the local SDC instance.
• Create an RRCP Banner and Epic named MPARTICLE_ATTRIBUTES_ containing an mParticle template and check that the template is replaced with the value from the test profile.
• Check that the mParticle attribute is used when selecting the variant.
• Create a regular Banner and Epic test without MPARTICLE_ATTRIBUTES_ in the name and check that the mParticle menu is not available and mParticle attributes are not required for variant selection.

How can we measure success?

For this PR it is being able to select Banner and Epic variants based on whether a user has the required mParticle attributes, and correctly substitute those attributes into the content.

The wider goal is to enable personalised messaging for users with the right mParticle attributes, and measure the impact through conversion rate and LTV3 per impression.

Screenshots

Banner:

Epic:

Accessibility

• Tested with screen reader
• Navigable with keyboard
• Colour contrast passed
• The change doesn't use only colour to convey meaning

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From guardian/actions-riff-raff.

[Copilot]

🟡 Changes recommended

Unresolved moderate issues remain in profile gating and template matching and substitution.

Get a fresh assessment by requesting another Copilot review.

Pull request overview

Adds mParticle attribute targeting and template substitution for Banner and Epic A/B tests.

Changes:

• Extends schemas and props with mParticle template configuration.
• Adds profile matching and content substitution helpers.
• Integrates targeting and substitution into selection and routers with unit tests.

File summaries

File	Reviewed changes
src/shared/types/props/epic.ts	Adds mParticle template props.
src/shared/types/props/banner.ts	Adds mParticle template props.
src/shared/types/abTests/epic.ts	Extends Epic test schema.
src/shared/types/abTests/banner.ts	Extends Banner test schema.
src/server/tests/headers/headerSelection.test.ts	Updates profile fixtures.
src/server/tests/epics/epicSelection.ts	Adds Epic template targeting.
src/server/tests/banners/bannerSelection.ts	Adds Banner template targeting.
src/server/lib/targeting.test.ts	Updates targeting fixtures.
src/server/lib/mParticleTemplates.ts	Implements matching and substitution.
src/server/lib/mParticleTemplates.test.ts	Tests template behavior.
src/server/lib/mParticle.ts	Supports optional profile attributes.
src/server/api/epicRouter.ts	Substitutes Epic content in responses.
src/server/api/bannerRouter.ts	Substitutes Banner content in responses.

Review details

Suppressed comments (2)

src/server/lib/mParticleTemplates.ts:24

• Eligibility checks attribute keys case-sensitively, but substitution deliberately resolves them case-insensitively. For example, a configured FIRST_NAME with a profile key first_name is rejected before the substitution that would have succeeded. Use the same case-insensitive key lookup for matching.

    for (const template of mParticleTemplates) {
        if (!mParticleProfile.user_attributes || !(template in mParticleProfile.user_attributes)) {
            return false;

src/server/lib/mParticleTemplates.ts:74

• The spread preserves user-visible fields such as cta.text, custom secondary-CTA text, and newsletter successDescription without substitution. Templates placed in any of those EpicVariant fields will therefore remain in the response; the variant helper needs to transform those nested content fields too.

    return {
        ...epicVariant,
        heading: updatedHeading,
        paragraphs: updatedParagraphs,
        highlightedText: updatedHighlightedText,
    };

• Files reviewed: 13/13 changed files
• Comments generated: 5
• Review effort level: Lite

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[tomrf1]

great!