Add missing tests for array utilities

Author: skovhus

server/src/util/__tests__/array.test.ts

@@ -0,0 +1,20 @@
+import { uniqueBasedOnHash } from '../array'
+
+describe('uniqueBasedOnHash', () => {
+  it('returns a list of unique elements', () => {
+    type Item = { x: string; y: number }
+
+    const items: Item[] = [
+      { x: '1', y: 1 },
+      { x: '1', y: 2 },
+      { x: '2', y: 3 },
+    ]
+
+    const hashFunction = ({ x }: Item) => x
+    const result = uniqueBasedOnHash(items, hashFunction)
+    expect(result).toEqual([
+      { x: '1', y: 1 },
+      { x: '2', y: 3 },
+    ])
+  })
+})