shadows/framework/src/main/java/org/robolectric/shadows/ShadowProcess.java
@Implementation
  protected static final void setThreadPriority(int tid, int priority) {
    checkArgument(
        priority >= android.os.Process.THREAD_PRIORITY_URGENT_AUDIO
            && priority <= android.os.Process.THREAD_PRIORITY_LOWEST,
        "priority %s out of range. Use a Process.THREAD_PRIORITY_* constant.",
        priority);

    if (tid == 0) {
      tid = ShadowProcess.myTid();
    }
    synchronized (threadPrioritiesLock) {
      threadPriorities.put(tid, priority);
    }
  }
@Implementation
  protected static final void setThreadPriority(int tid, int priority) {
    checkArgument(
        priority >= android.os.Process.THREAD_PRIORITY_URGENT_AUDIO
            && priority <= android.os.Process.THREAD_PRIORITY_LOWEST,
        "priority %s out of range. Use a Process.THREAD_PRIORITY_* constant.",
        priority);

    if (tid == 0) {
      tid = ShadowProcess.myTid();
    }
    synchronized (threadPrioritiesLock) {
      threadPriorities.put(tid, priority);
    }
  }
Stores priority for the given thread, but doesn't actually change it to not mess up with test
runner. Unlike real implementation does not throw any exceptions.

@param tid The identifier of the thread. If equals zero, the identifier of the calling thread
will be used.