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apps/server/src/database/helpers/page-hierarchy-cycle.spec.ts

@@ -0,0 +1,53 @@
+import {
+  assertAcyclicPageTraversal,
+  PageHierarchyCycleError,
+  stripPageTraversalMetadata,
+} from './page-hierarchy-cycle';
+
+describe('page hierarchy cycle contract', () => {
+  it('does nothing when no row is marked as a cycle', () => {
+    expect(() =>
+      assertAcyclicPageTraversal(
+        [
+          { id: 'page-1', title: 'Root', isCycle: false },
+          { id: 'page-2', title: 'Child', isCycle: false },
+        ],
+        'page-1',
+      ),
+    ).not.toThrow();
+  });
+
+  it('throws PageHierarchyCycleError when a row is marked as a cycle', () => {
+    expect(() =>
+      assertAcyclicPageTraversal(
+        [{ id: 'page-1', title: 'Root', isCycle: true }],
+        'page-1',
+      ),
+    ).toThrow(PageHierarchyCycleError);
+  });
+
+  it('keeps the root page id on the error for safe logging', () => {
+    try {
+      assertAcyclicPageTraversal(
+        [{ id: 'page-1', title: 'Root', isCycle: true }],
+        'root-page',
+      );
+      throw new Error('expected a cycle error');
+    } catch (error) {
+      expect(error).toBeInstanceOf(PageHierarchyCycleError);
+      expect((error as PageHierarchyCycleError).rootPageId).toBe('root-page');
+      expect((error as PageHierarchyCycleError).code).toBe(
+        'PAGE_HIERARCHY_CYCLE',
+      );
+    }
+  });
+
+  it('removes traversal metadata without changing the public row fields', () => {
+    const row = { id: 'page-1', title: 'Root', isCycle: false };
+
+    expect(stripPageTraversalMetadata(row)).toEqual({
+      id: 'page-1',
+      title: 'Root',
+    });
+  });
+});