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Control uses of rand() in test scripts #301
Description
The test scripts use random number generator to e.g. change the sleep times.
This is wonderful for stress tests, but a really bad idea for CI and daily tests, since by definition these tests cannot be reproduced UNLESS the seed is known.
We should add one option to tests that use random numbers, so that by default we shall use the same seed - 42
https://en.wikipedia.org/wiki/Phrases_from_The_Hitchhiker%27s_Guide_to_the_Galaxy#Answer_to_the_Ultimate_Question_of_Life,_the_Universe,_and_Everything_(42)
When the user wishes more randomness, the seed shall be saved in the logs so that we can reproduce failures.
This can be done in bash with the RANDOM variable
Normal case:
$ T=42
$ RANDOM=$T; echo $RANDOM; echo $RANDOM; echo $RANDOM
17766
11151
23481
$ RANDOM=$T; echo $RANDOM; echo $RANDOM; echo $RANDOM
17766
11151
23481stress-test:
$ T=$(date +%s)
$ echo $T
1596129567
$ RANDOM=$T; echo $RANDOM; echo $RANDOM;
19204
11943
$ RANDOM=$T; echo $RANDOM; echo $RANDOM;
19204
11943
$ RANDOM=$T; echo $RANDOM; echo $RANDOM;
19204
11943cc:
Reacted by Marc Herbert
Activity
marc-hb commentedon Jul 31, 2020
As suggested by @xiulipan : the best option is a command flag that lets the caller choose between constant seed parameter (with a default value) versus truly random seed.
My suggestions:
xiulipan commentedon Jul 31, 2020
thanks @marc-hb for the suggestion. I will take them with the new feature implement.
Another feature:
marc-hb commentedon Jul 31, 2020
Yes that's what I meant by "... so it can be re-used". Rephrasing the previous comment.