txscript/hashcache_test: fix flake due to resetting RNG #1689
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TestHashCacheAddContainsHashes flakes fairly regularly when rebasing PR btcsuite#1684 with: txid <txid> wasn't inserted into cache but was found. With probabilty 1/10^2 there will be no inputs on the transaction. This reduces the entropy in the txid, and I belive is the primary cause of the flake.
This resolves the more fundamental flake in the unit tests noted in the prior commit. Because multiple unit tests call rand.Seed in parallel, it's possible they can be executed with the same unix timestamp (in seconds). If the second call happens between generating the hash cache and checking that the cache doesn't contain a random txn, the random transaction is in fact a duplicate of one generated earlier since the RNG state was reset. To remedy, we initialize rand.Seed once in the init function.
1 task
onyb
approved these changes
Feb 2, 2021
Pull Request Test Coverage Report for Build 532036009
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Nice catch! I'd even forgotten I'd written this initial hash cache implementation back in the day :p |
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Encountered this while rebasing #1684, see commit msgs for more details