static Map<ProcessId, Map<String, Optional<String>>> getProcessRacksForAllProcess() {
        return mkMap(
            mkEntry(PID_1, mkMap(mkEntry("1", Optional.of(RACK_0)))),
            mkEntry(PID_2, mkMap(mkEntry("1", Optional.of(RACK_1)))),
            mkEntry(PID_3, mkMap(mkEntry("1", Optional.of(RACK_2)))),
            mkEntry(PID_4, mkMap(mkEntry("1", Optional.of(RACK_3)))),
            mkEntry(PID_5, mkMap(mkEntry("1", Optional.of(RACK_4)))),
            mkEntry(PID_6, mkMap(mkEntry("1", Optional.of(RACK_0)))),
            mkEntry(PID_7, mkMap(mkEntry("1", Optional.of(RACK_1))))
        );
    }
Builds a ProcessId with a UUID by repeating the given number n. For valid n, it is guaranteed that the returned UUIDs satisfy
the same relation relative to others as their parameter n does: iff n < m, then uuidForInt(n) < uuidForInt(m)
streams/src/test/java/org/apache/kafka/streams/processor/internals/assignment/AssignmentTestUtils.java