Adds our first 'real' unit tests

Fixes #141

package.json

@@ -10,7 +10,8 @@
 		"lint": "prettier --check . && eslint .",
 		"lint:prettier": "prettier --check .",
 		"lint:eslint": "eslint .",
-		"format": "prettier --write ."
+		"format": "prettier --write .",
+		"prepush": "prettier --write . && prettier --check . && eslint . && vitest run"
 	},
 	"devDependencies": {
 		"@fortawesome/fontawesome-svg-core": "^6.5.2",

src/tests/lib/formatters.test.js

@@ -0,0 +1,16 @@
+import { describe, it, expect } from 'vitest';
+import { convertUnixToTime } from '$lib/formatters';
+
+describe('convertUnixToTime', () => {
+	it('returns a blank string when its input is null', () => {
+		expect(convertUnixToTime(null)).toBe('');
+	});
+
+	it('returns a blank string when its input is an empty string', () => {
+		expect(convertUnixToTime('')).toBe('');
+	});
+
+	it('converts a Unix timestamp to a locale-specific formatted time', () => {
+		expect(convertUnixToTime(1727442050)).toBe('01:00 PM');
+	});
+});