QtScript have a great test covrage, but it could be even better.
Now the QScriptValue autotest use a set of values to check API, the set is initialized before each test case. Because of a lazy nature of a QScriptValue object, it is not perfect. The value after first contact with an engine get bound to it, so all other tests check modified version of the value. This was the main cause why bug 42363 was found in a benchmarks and not in an autotests.
I propose to recreate all values before each test.