add failing test for #44

Author: Qix-

test/basic.js

@@ -180,3 +180,7 @@ assert.equal(string.to.hwb([280, 40, 60], 0), 'hwb(280, 40%, 60%, 0)');
 
 assert.equal(string.to.keyword([255, 255, 0]), 'yellow');
 assert.equal(string.to.keyword([100, 255, 0]), undefined);
+
+// Make sure .get() doesn't return object prototype values (regression test, #44)
+Object.keys(Object.getOwnPropertyDescriptors(Object.prototype))
+	.map(property => assert.deepStrictEqual([property, string.get(property)], [property, null]));