Add tests for exported function

Added tests for _sanitizeFontName function to validate font name sanitization rules.

Author: perminder-17

test/unit/type/p5.Font.js

@@ -1,4 +1,5 @@
 import p5 from '../../../src/app.js';
+import {_sanitizeFontName} from '../../../src/type/p5.Font.js';
 
 suite('p5.Font', function () {
   var myp5;
@@ -51,3 +52,23 @@ suite('p5.Font', function () {
     });
   });
 });
+
+suite('sanitizeFontName', function () {
+  test('fully alphabetic or alpha-leading alnum do not need quotes', function () {
+    assert.equal(_sanitizeFontName('Arial'), 'Arial');
+    assert.equal(_sanitizeFontName('Family900'), 'Family900');
+    assert.equal(_sanitizeFontName('A_b-c'), 'A_b-c');
+  });
+
+  test('names starting with a digit need quotes', function () {
+    assert.equal(_sanitizeFontName('9lives'), "'9lives'");
+  });
+
+  test('names with spaces need quotes', function () {
+    assert.equal(_sanitizeFontName('My Font'), "'My Font'");
+  });
+
+  test('names with commas need quotes', function () {
+    assert.equal(_sanitizeFontName('Foo,Bar'), "'Foo,Bar'");
+  });
+});