test: add test for findOffsets() util (#420)

Author: lumirlumir

tests/util.test.js

@@ -0,0 +1,57 @@
+/**
+ * @fileoverview Tests for util.js
+ * @author 루밀LuMir(lumirlumir)
+ */
+
+//------------------------------------------------------------------------------
+// Imports
+//------------------------------------------------------------------------------
+
+import assert from "node:assert";
+import { findOffsets } from "../src/util.js";
+
+//------------------------------------------------------------------------------
+// Tests
+//------------------------------------------------------------------------------
+
+describe("util", () => {
+	describe("findOffsets()", () => {
+		it("should return correct offsets for a simple string", () => {
+			const text = "Hello world!";
+			const offset = 6; // 'w' in "world"
+			const result = findOffsets(text, offset);
+			assert.deepStrictEqual(result, { lineOffset: 0, columnOffset: 6 });
+		});
+
+		it("should handle line breaks correctly", () => {
+			const text = "Hello\nworld!";
+			const offset = 6; // 'w' in "world"
+			const result = findOffsets(text, offset);
+			assert.deepStrictEqual(result, { lineOffset: 1, columnOffset: 0 });
+		});
+
+		it("should handle Windows-style line endings", () => {
+			const text = "Hello\r\nworld!";
+			const offset = 7; // 'w' in "world"
+			const result = findOffsets(text, offset);
+			assert.deepStrictEqual(result, { lineOffset: 1, columnOffset: 0 });
+		});
+
+		it("should handle offsets at the start of the string", () => {
+			const text = "Hello, world!";
+			const offset = 0; // Start of the string
+			const result = findOffsets(text, offset);
+			assert.deepStrictEqual(result, { lineOffset: 0, columnOffset: 0 });
+		});
+
+		it("should handle offsets at the end of the string", () => {
+			const text = "Hello, world!";
+			const offset = text.length - 1; // Last character '!'
+			const result = findOffsets(text, offset);
+			assert.deepStrictEqual(result, {
+				lineOffset: 0,
+				columnOffset: text.length - 1,
+			});
+		});
+	});
+});