diff --git a/src/data/helpers/index.test.ts b/src/data/helpers/index.test.ts
new file mode 100644
index 0000000..cd1f399
--- /dev/null
+++ b/src/data/helpers/index.test.ts
@@ -0,0 +1,42 @@
+import { findClosestTopic } from './';
+
+describe('findClosestTopic', () => {
+  const legalTopics = [
+    {
+      name: 'Housing',
+      codes: ['HO-01-00-00-00', 'HO-02-00-00-00'],
+    },
+    {
+      name: 'Family',
+      codes: ['FA-00-00-00-00', 'FA-01-00-00-00'],
+    },
+    {
+      name: 'Employment',
+      codes: ['EM-01-00-00-00'],
+    },
+  ];
+
+  it('should return the exact matching topic', () => {
+    const topicCode = 'HO-02-00-00-00';
+    const result = findClosestTopic(topicCode, legalTopics);
+    expect(result.name).toBe('Housing');
+  });
+
+  it('should return the closest smaller match if exact match is not available', () => {
+    const topicCode = 'HO-01-50-00-00';
+    const result = findClosestTopic(topicCode, legalTopics);
+    expect(result.name).toBe('Housing');
+  });
+
+  it('should return undefined if no prefix matches', () => {
+    const topicCode = 'XX-01-00-00-00';
+    const result = findClosestTopic(topicCode, legalTopics);
+    expect(result).toBeUndefined();
+  });
+
+  it('handles cases with leading zeros in topic codes', () => {
+    const topicCode = 'FA-01-00-00-00';
+    const result = findClosestTopic(topicCode, legalTopics);
+    expect(result.name).toBe('Family');
+  });
+});