utils: test intersection

src/utils.test.ts

@@ -0,0 +1,27 @@
+import { describe, it, expect } from "vitest";
+
+import { intersection } from "./utils";
+
+describe("intersection function", () => {
+  it("returns the correct intersection of two arrays with common elements", () => {
+    expect(intersection([1, 2, 3], [2, 3, 4])).toEqual([2, 3]);
+  });
+
+  it("returns an empty array when there are no common elements", () => {
+    expect(intersection([1, 2, 3], [4, 5, 6])).toEqual([]);
+  });
+
+  it("handles identical arrays correctly", () => {
+    expect(intersection([1, 2, 3], [1, 2, 3])).toEqual([1, 2, 3]);
+  });
+
+  it("returns an empty array when one or both input arrays are empty", () => {
+    expect(intersection([], [1, 2, 3])).toEqual([]);
+    expect(intersection([1, 2, 3], [])).toEqual([]);
+    expect(intersection([], [])).toEqual([]);
+  });
+
+  it("correctly handles duplicates in the input arrays", () => {
+    expect(intersection([1, 2, 2, 3], [2, 2, 3, 4])).toEqual([2, 2, 3]);
+  });
+});