For Case [1] I got an unrelated CI failure [2] for NeoUUIDGeneratorTests>>#testTwoSameGenerator Checking this locally by running this a dozen times... 1 to: 1000 do: [:n| last:=n. NeoUUIDGeneratorTests new setUp testTwoSameGenerator ] Two distinct failures are apparent... 1. Takes longer than expected. self assert: (time2 - time1) abs < 100 last=1 ==> a time difference of 109 last=1 ==> a time difference of 102 last=1 ==> a time difference of 155 last=1 ==> a time difference of 105 Interesting that whenever this happens its on the first iteration. 2. Invalid consecutive ids. self assert: (uuid1 at: 10) + 1 equals: (uuid2 at: 10). last=127 ==> TestFailure: Got 256 instead of 0. last=828 ==> TestFailure: Got 256 instead of 0. last=128 ==> TestFailure: Got 256 instead of 0. last=316 ==> TestFailure: Got 256 instead of 0. Maybe a problem with rollover? So instrumenting a bit: testTwoSameGenerator: n | uuid1 uuid2 consecutiveOk time1 time2 timeOk | .... "same generator, consequetive counters" consecutiveOk := ((uuid1 at: 10) + 1) = (uuid2 at: 10). "same generators, similar clock, within 100 milliseconds" time1 := self timeFromUUID: uuid1. time2 := self timeFromUUID: uuid2. timeOk := (time2 - time1) abs < 100. ( timeOk and: [ consecutiveOk ]) ifFalse: [ Transcript cr; show: 'fail n=', (n printPaddedWith: $0 to: 3) ; tab; show: ' time ', ((time2 - time1) printString) , '<100'; tab; show: ' uuid ', (((uuid1 at: 10) + 1) printString, '=', (uuid2 at: 10) printString). ]. self assert: consecutiveOk. self assert: timeOk.
From playground running... 1 to: 1000 do: [:n| NeoUUIDGeneratorTests new setUp testTwoSameGenerator: n]. Transcript crShow: 'x'.
Note the 'x' was not output due to one of the consecutiveOk or timeOk asserts triggered each run. fail n=001 time 104<100 uuid 160=160 fail n=269 time 2<100 uuid 256=0 fail n=001 time 152<100 uuid 166=166 fail n=117 time 3<100 uuid 256=0 fail n=001 time 123<100 uuid 128=128 fail n=278 time 3<100 uuid 256=0 fail n=001 time 145<100 uuid 230=230 fail n=673 time 1340<100 uuid 141=141 fail n=707 time 3<100 uuid 256=0 fail n=001 time 132<100 uuid 73=73 fail n=001 time 117<100 uuid 206=206 fail n=063 time 2<100 uuid 256=0 fail n=345 time 3<100 uuid 256=0 Now a strange thing is that after commenting out those two asserts for consecutiveOk and timeOk, the fails at n=001 stop happening. fail n=001 time 141<100 uuid 232=232 x x fail n=201 time 3<100 uuid 256=0 fail n=268 time 3<100 uuid 256=0 fail n=359 time 3<100 uuid 256=0 fail n=408 time 2<100 uuid 256=0 fail n=559 time 3<100 uuid 256=0 x fail n=139 time 3<100 uuid 256=0 fail n=854 time 7<100 uuid 256=0 x fail n=389 time 3<100 uuid 256=0 fail n=669 time 3<100 uuid 256=0 fail n=876 time 3<100 uuid 256=0 fail n=916 time 3<100 uuid 256=0 fail n=953 time 2<100 uuid 256=0 fail n=954 time 3<100 uuid 256=0 x fail n=148 time 3<100 uuid 256=0 fail n=741 time 3<100 uuid 256=0 x fail n=116 time 2<100 uuid 256=0 fail n=480 time 3<100 uuid 256=0 x After treating the rollover like this... consecutiveOk := ((uuid1 at: 10) + 1) \\ 256 = (uuid2 at: 10). running the last playground script gives... (Note the n=001 fail reoccurs after waiting a while between running the playground script again.) fail n=001 time 123<100 uuid 110=110 x fail n=345 time 1287<100 uuid 24=24 fail n=404 time 1313<100 uuid 125=125 x x x x x fail n=449 time 1290<100 uuid 24=24 x x x x x Thats looking better, so upping to 10000 iterations... fail n=0001 time 151<100 uuid 160=160 fail n=2977 time 1437<100 uuid 221=221 fail n=5498 time 1454<100 uuid 224=224 fail n=9007 time 1351<100 uuid 239=239 x fail n=3389 time 1381<100 uuid 223=223 fail n=7768 time 1365<100 uuid 82=82 fail n=9773 time 1395<100 uuid 164=164 x fail n=3325 time 1448<100 uuid 67=67 fail n=9930 time 1456<100 uuid 103=103 x fail n=0060 time 2914<100 uuid 159=159 fail n=1829 time 1438<100 uuid 32=32 fail n=7918 time 1436<100 uuid 182=182 x So the rollover looks cured. Now adding some more instrumentation to view GC Time and Time To Run and (see attached ST file) 0:00:00:00 TTR 0:00:00:00.001 TTR 0:00:00:00 TTR 0:00:00:00 TTR 0:00:00:00 TTR 0:00:00:00 TTR 0:00:00:00 TTR 0:00:00:00 TTR 0:00:00:00 TTR 0:00:00:00 x fail n=0001 time 115<100 uuid 157=157 GCTime 0 TTR 0:00:00:00 fail n=0001 time 2<100 uuid 255=0 GCTime 0 TTR 0:00:00:00 x fail n=0001 time 111<100 uuid 104=104 GCTime 0 TTR 0 x fail n=0001 time 120<100 uuid 204=204 GCTime 0 TTR 0 fail n=0001 time 1182<100 uuid 103=103 GCTime 1 TTR 1 x x x x x fail n=0001 time 3<100 uuid 255=0 GCTime 0 TTR 0 x x fail n=0001 time 1251<100 uuid 253=253 GCTime 2 TTR 1 x Now I wonder at the class comment saying... "the first 8 bytes are the *millisecond* clock value" but #clockOn: is using *microsecond* clock. Perhaps "self assert: (time2 - time1) abs < 100" is meant to be 100ms not 100us ?? cheers -ben [1] https://pharo.fogbugz.com/f/cases/19438 [2] https://ci.inria.fr/pharo/job/Pharo-6.0-Issue-Validator/19471//artifact/vali...