That’s actually the issue I was trying to highlight. In JRuby, the default thread priority is 5, with a maximum of 10 and the minimum of 1. Setting the priority to 1 has the effect of raising the priority on MRI but lowering it on JRuby. This could lead to surprising thread scheduling when porting a program from MRI to JRuby (or vice versa).

Even if I removed these two specs, the `"can decrease the priority"` spec would still fail, since `-1` falls outside the JVM range.