Update index-tests.ts

resolve-from/index-tests.ts

@@ -1,5 +1,6 @@
+/// <reference path="index.d.ts" />
+
 // Much better testing in https://github.com/typed-typings/typed-resolve-from
-
-import resolveFrom = require('resolve-from');
-
-console.log(typeof resolveFrom === 'function');
+if (typeof resolveFrom !== 'function') {
+  throw new Error('resolveFrom is not a function');
+}