test(#141): add unit tests for invalid icon configs

Focus: making sure vivify-server doesn't crash when an icon option has a
mistake, but instead falls back to fallbackIcon with a console warning.

Author: tuurep

package.json

@@ -7,7 +7,7 @@
     "viv": "VIV_PORT=3000 node --loader ts-node/esm src/app.ts",
     "lint": "eslint src static",
     "lint-markdown": "markdownlint-cli2 --config .github/.markdownlint-cli2.yaml",
-    "test": "node --loader ts-node/esm tests/unit/cli.ts",
+    "test": "node --loader ts-node/esm --test tests/unit/cli.ts tests/unit/alerts.ts",
     "deduplicate": "yarn-deduplicate"
   },
   "type": "module",

src/parser/alerts.ts

@@ -125,3 +125,4 @@ const capitalize = (str: string) => {
 };
 
 export default MarkdownItAlerts;
+export { resolveIcon }; // Exported for unit test

tests/unit/alerts.ts

@@ -0,0 +1,66 @@
+import assert from 'node:assert';
+import test, { describe } from 'node:test';
+
+import { resolveIcon } from '../../src/parser/alerts.js';
+
+const assertFallback = (result: string) => {
+    // We know a fallback icon is returned when result starts with this
+    assert.match(result, /^<script>console\.warn\(/);
+    // Contains the actual fallback icon
+    assert.match(result, /<svg/);
+};
+
+// Tests to make sure vivify-server isn't crashing on invalid options in
+// config.alertsOptions
+describe('resolveIcon returns fallback icon', () => {
+    test('empty string', () => {
+        assertFallback(resolveIcon('')); // empty string is considered (invalid) octicon name
+    });
+
+    test('invalid octicon name', () => {
+        assertFallback(resolveIcon('foo-bar'));         // nonexistent
+        assertFallback(resolveIcon('04trweäöcaöe'));    // garbage
+        assertFallback(resolveIcon('CircleSlashIcon')); // real icon but should be kebab-case
+    });
+
+    test('valid paths but icon not found', () => {
+        assertFallback(resolveIcon('/home/john/icons/flower.svg'));
+        assertFallback(resolveIcon('~/icons/flower.svg'));
+        assertFallback(resolveIcon('./alert-icons/gear.svg'));
+        assertFallback(resolveIcon('../../svgs/dog.svg'));
+    });
+
+    test('invalid paths', () => {
+        assertFallback(resolveIcon('//home/john/icons/flower.svg')); // double slash
+        assertFallback(resolveIcon('/home/john//icons/flower.svg')); // double slash alt
+        assertFallback(resolveIcon('./alert icons/gear.svg'));       // unescaped space
+    });
+
+    test('misclassified invalid paths', () => {
+        // Considered to be (invalid) octicon names
+        assertFallback(resolveIcon('home/john/icons/flower.svg')); // missing beginning slash
+        assertFallback(resolveIcon('~icons/flower.svg'));
+    });
+
+    test('missing .svg extension', () => {
+        // Considered to be (invalid) octicon names
+        assertFallback(resolveIcon('/home/john/icons/flower'));
+        assertFallback(resolveIcon('~/icons/flower'));
+        assertFallback(resolveIcon('./alert-icons/gear'));
+        assertFallback(resolveIcon('../../svgs/dog'));
+    });
+
+    test('wrong file extension', () => {
+        // Considered to be (invalid) octicon names
+        assertFallback(resolveIcon('/home/john/icons/flower.png'));
+        assertFallback(resolveIcon('~/icons/flower.jpg'));
+        assertFallback(resolveIcon('./alert-icons/gear.txt'));
+        assertFallback(resolveIcon('../../svgs/dog.ico'));
+    });
+
+    test('wrong tag', () => {
+        // Considered to be (invalid) octicon names
+        assertFallback(resolveIcon("<img src='flower.png' alt='Alert icon hehe'>"));
+        assertFallback(resolveIcon('<script>document.createElement("svg");</script>'));
+    });
+});