add test

test/api.ts

@@ -19,6 +19,14 @@ https://github.com/syuilo/ai
 after`;
 			assert.strictEqual(mfm.toString(mfm.parse(input)), input);
 		});
+
+		it('preserve url brackets', () => {
+			const input1 = `https://github.com/syuilo/ai`;
+			assert.strictEqual(mfm.toString(mfm.parse(input1)), input1);
+
+			const input2 = `<https://github.com/syuilo/ai>`;
+			assert.strictEqual(mfm.toString(mfm.parse(input2)), input2);
+		});
 	});
 
 	describe('inspect', () => {