From 7a60e64a8429e0f0b87c15d234758dfa0a38e1f2 Mon Sep 17 00:00:00 2001
From: robbond <rob@rdbsolutions.co.uk>
Date: Thu, 9 Apr 2026 15:06:41 +0100
Subject: [PATCH] test(breadcrumbs): assert strict null on non-exact route map
 lookups

---
 memory-bank/change-log.md                     | 30 +++++++++++
 .../breadcrumb-route-maps-helper.test.cjs     | 50 +++++++++++++++++++
 2 files changed, 80 insertions(+)

diff --git a/memory-bank/change-log.md b/memory-bank/change-log.md
index 124e7eec..f303f84e 100644
--- a/memory-bank/change-log.md
+++ b/memory-bank/change-log.md
@@ -754,6 +754,36 @@ Follow-ups:
 - Next smaller slice candidate: add focused helper test for strict null behavior on empty-string/whitespace/non-exact path keys.
 - Next larger slice candidate: evaluate extractability of `/myportal/representation` back-link states via explicit callback injection, only if questionnaire/submit side-effects remain parity-safe and readable.
 
+### CL-22541-X: breadcrumbs smaller slice — strict null lookup guard coverage (empty/whitespace/non-exact paths)
+
+date: 2026-04-09  
+author: Cline  
+scope: `tests/phase22/breadcrumb-route-maps-helper.test.cjs`  
+type: change  
+rationale: Execute the queued smaller follow-up slice by hardening helper regression coverage for strict exact-match route lookup semantics.
+impact: Test-only hardening; no runtime route/auth/session/API/EN-CY/a11y behavior change.
+status: completed
+
+Summary:
+
+- Added focused helper-level test case in `tests/phase22/breadcrumb-route-maps-helper.test.cjs`:
+    - `resolveMappedRouteRenderer returns null for empty, whitespace, and non-exact path variants`
+- New assertions verify resolver returns `null` for:
+    - empty path (`""`)
+    - whitespace-only path (`"   "`)
+    - trailing/leading whitespace variants (`"/known "`, `" /known"`)
+    - case-variant non-exact key (`"/KNOWN"`)
+- Confirms route-map resolver remains strict/exact and does not auto-trim or case-normalize lookup keys.
+
+Validation:
+
+- `npx eslint tests/phase22/breadcrumb-route-maps-helper.test.cjs tests/phase22/index.test.cjs` -> pass.
+- `node tests/phase22/index.test.cjs` -> pass (combined suite; breadcrumb-route-maps-helper 6/6).
+
+Follow-ups:
+
+- Next larger slice candidate remains `/myportal/representation` callback/state branch extraction only if side-effects can be injected/parity-preserved cleanly.
+
 ### CL-00X: 22500 `components/elements/index.js` Phase 1 helper extraction
 
 date: 2026-04-07  
diff --git a/tests/phase22/breadcrumb-route-maps-helper.test.cjs b/tests/phase22/breadcrumb-route-maps-helper.test.cjs
index 3dec5147..30c627bf 100644
--- a/tests/phase22/breadcrumb-route-maps-helper.test.cjs
+++ b/tests/phase22/breadcrumb-route-maps-helper.test.cjs
@@ -215,6 +215,56 @@ test("resolveMappedRouteRenderer returns null for unmapped path", () => {
     );
 });
 
+test("resolveMappedRouteRenderer returns null for empty, whitespace, and non-exact path variants", () => {
+    const { buildBreadcrumbRendererMaps, resolveMappedRouteRenderer } =
+        loadHelpers();
+
+    const knownRenderer = () => "known";
+
+    const maps = buildBreadcrumbRendererMaps({
+        simpleRouteRenderersByPath: {
+            "/known": knownRenderer
+        },
+        simpleLinkTextPairRenderersByPath: {},
+        simpleMyPortalRouteRenderersByPath: {},
+        newAppealRouteRenderersByPath: {},
+        callbackRouteRenderersByPath: {},
+        stepBackRouteRenderersByPath: {},
+        caseDetailRouteRenderersByPath: {},
+        detailAndAccountRouteRenderersByPath: {}
+    });
+
+    assert.strictEqual(
+        resolveMappedRouteRenderer("", maps),
+        null,
+        "Expected null for empty path lookup when no empty key is mapped"
+    );
+
+    assert.strictEqual(
+        resolveMappedRouteRenderer("   ", maps),
+        null,
+        "Expected null for whitespace-only path lookup"
+    );
+
+    assert.strictEqual(
+        resolveMappedRouteRenderer("/known ", maps),
+        null,
+        "Expected null for non-exact path variant with trailing whitespace"
+    );
+
+    assert.strictEqual(
+        resolveMappedRouteRenderer(" /known", maps),
+        null,
+        "Expected null for non-exact path variant with leading whitespace"
+    );
+
+    assert.strictEqual(
+        resolveMappedRouteRenderer("/KNOWN", maps),
+        null,
+        "Expected null for non-exact case-variant path lookup"
+    );
+});
+
 test("resolveMappedRouteRenderer skips invalid map entries and non-function renderer values", () => {
     const { buildBreadcrumbRendererMaps, resolveMappedRouteRenderer } =
         loadHelpers();