Add failing test for client-side router filtering

test/unit/create-client-router-filter.test.ts

@@ -0,0 +1,29 @@
+/* eslint-env jest */
+import { createClientRouterFilter } from 'next/dist/lib/create-client-router-filter'
+import { BloomFilter } from 'next/dist/shared/lib/bloom-filter'
+
+describe('createClientRouterFilter', () => {
+  it('creates a filter that does not collide with wildly different path names', () => {
+    const { staticFilter, dynamicFilter } = createClientRouterFilter(
+      ['/_not-found', '/a/[lang]/corporate', '/a/[lang]/gift'], // Routes are based on BOTM's app router migration project.
+      []
+    )
+
+    const staticFilterInstance = new BloomFilter(
+      staticFilter.numItems,
+      staticFilter.errorRate
+    )
+    staticFilterInstance.import(staticFilter)
+    const dynamicFilterInstance = new BloomFilter(
+      dynamicFilter.numItems,
+      dynamicFilter.errorRate
+    )
+    dynamicFilterInstance.import(dynamicFilter)
+
+    expect(
+      staticFilterInstance.contains(
+        '/all-hardcovers/no-one-can-know-1511?category=current-features'
+      )
+    ).toBe(false)
+  })
+})