least ancestral entity constraint tests

package.json

@@ -88,6 +88,7 @@
     "@veupathdb/tsconfig": "^2.0.0",
     "@veupathdb/wdk-client": "^0.9.29",
     "assert": "^2.0.0",
+    "babel-jest": "^29.5.0",
     "bubleify": "^2.0.0",
     "buffer": "^6.0.3",
     "http-proxy-middleware": "^2.0.6",

src/lib/core/__test__/utils/data-element-constraints.test.ts

@@ -0,0 +1,76 @@
+import { StudyEntity } from '../../types/study';
+import { leastAncestralEntity } from '../../utils/data-element-constraints';
+import { entityTreeToArray } from '../../utils/study-metadata';
+
+const mockStudyTree: StudyEntity = {
+  id: 'root',
+  idColumnName: 'colname',
+  displayName: 'nice label',
+  description: 'none',
+  variables: [],
+  children: [
+    {
+      id: 'branchA',
+      idColumnName: 'colname',
+      displayName: 'nice label',
+      description: 'none',
+      variables: [],
+      children: [
+        {
+          id: 'leafA1',
+          idColumnName: 'colname',
+          displayName: 'nice label',
+          description: 'none',
+          variables: [],
+        },
+        {
+          id: 'leafA2',
+          idColumnName: 'colname',
+          displayName: 'nice label',
+          description: 'none',
+          variables: [],
+        },
+      ],
+    },
+    {
+      id: 'branchB',
+      idColumnName: 'colname',
+      displayName: 'nice label',
+      description: 'none',
+      variables: [],
+      children: [
+        {
+          id: 'leafB1',
+          idColumnName: 'colname',
+          displayName: 'nice label',
+          description: 'none',
+          variables: [],
+        },
+        {
+          id: 'leafB2',
+          idColumnName: 'colname',
+          displayName: 'nice label',
+          description: 'none',
+          variables: [],
+        },
+      ],
+    },
+  ],
+};
+
+const studyEntities = entityTreeToArray(mockStudyTree);
+
+const branchA = studyEntities.find((e) => (e.id = 'branchA'))!;
+const branchB = studyEntities.find((e) => (e.id = 'branchB'))!;
+const leafA1 = studyEntities.find((e) => (e.id = 'leafA1'))!;
+const leafA2 = studyEntities.find((e) => (e.id = 'leafA2'))!;
+const leafB1 = studyEntities.find((e) => (e.id = 'leafB1'))!;
+const leafB2 = studyEntities.find((e) => (e.id = 'leafB2'))!;
+
+describe('leastAncestralEntity', () => {
+  it('should find leafA1 to be least ancestral in [branchA, leafA1]', () => {
+    expect(leastAncestralEntity([branchA, leafA1], studyEntities)).toEqual(
+      leafA1
+    );
+  });
+});