test(frontend): improve frontend test breadth for search controller

[SaitejaKommi]

Summary

This PR begins closing the frontend coverage gap by adding explicit tests for the central search controller mixin responsible for orchestrating search URL mappings, parameters, and signal-driven interactions.

It introduces a dedicated test harness to validate core state behavior, DOM interactions, and component instance isolation, reducing regression risk in complex controller flows.

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Related Issue

Fixes #403

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What Changed

Added Dedicated Test Harness

Created:

• search-ctl_test.ts

Introduced Mock Controller Component

Added DummySearchCtl, a lightweight test component wrapping the search mixin to expose:

• Controller properties
• Internal state behavior
• DOM parsing logic
• Signal/event interactions

Expanded Coverage

Added tests covering:

• autoLaunch override behavior
• Signal event capture from events such as SearchaliciousEvents.FACET_SELECTED
• Component name separation / multi-instance isolation rules
• Core controller property interactions

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Affected Files

• search-ctl_test.ts

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Testing

Verification gateway executed successfully:

• Backend unit tests ✅
• Backend integration tests ✅
• Frontend build/tests (dev) ✅
• Frontend build/tests (prod) ✅

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Notes

This is a frontend quality improvement focused on increasing confidence around complex search controller state transitions and preventing regressions.