tests: regtest: make test_just_in_time less flaky
What the developer wrote
Authored by f321x
tests: regtest: make test_just_in_time less flaky
The regtest just_in_time is flaky on the CI because it tries to open
two channels right after each other (mining 3 blocks in between).
If the channel opener (LSP/Bob) hasn't caught up yet and is still
on the same height as the previous channel open it will refuse to open
another channel due to the anchor channel key derivation limitation.
This adds a helper to pause the test until bob has caught up to the newly
mined 3 blocks before attempting the second open.
What changed, and why it matters
This commit only changes a test script. It adds a wait helper so a test that opens two Lightning channels in a row does not fail randomly on continuous integration. There is no change to Electrum's actual wallet or Lightning code, so users are not affected.
No security action needed. Treat as a normal test-stability improvement.
Security signals we found
No strong security signals were identified.
Evidence from the diff
The patch modifies tests/regtest/regtest.sh. It introduces wait_for_chain_tip(), which polls until a named Electrum daemon reports a blockchain_height matching bitcoind’s block count, then calls wait_for_sync. The just_in_time test scenario now calls this helper for ‘bob’ after mining three blocks and before the second JIT channel open. The stated reason is to avoid a race where Bob has not processed the new blocks, causing the second anchor channel open to be refused due to key-derivation constraints. This is purely a test reliability fix.
Changed components
tests/regtest/regtest.shInspect captured patch +23 / −0
diff --git a/tests/regtest/regtest.sh b/tests/regtest/regtest.sh
index f5df1e5..30edab0 100755
--- a/tests/regtest/regtest.sh
+++ b/tests/regtest/regtest.sh
@@ -144,6 +144,28 @@ function wait_until_spent()
printf "\n"
}
+function wait_for_chain_tip()
+{
+ msg="waiting until $1 catches up to chain tip"
+ cmd="./run_electrum --regtest -D /tmp/$1"
+ declare -i timeout_sec=120
+ declare -i elapsed_sec=0
+
+ printf "$msg"
+ while (( $($cmd getinfo | jq '.blockchain_height') < $($bitcoin_cli getblockcount) )); do
+ if ((elapsed_sec > timeout_sec)); then
+ printf "Timeout of %i s exceeded\n" "$elapsed_sec"
+ exit 1
+ fi
+ sleep 1
+ elapsed_sec=$((elapsed_sec + 1))
+ printf '.'
+ done
+
+ $cmd wait_for_sync > /dev/null
+ printf "\n"
+}
+
function assert_utxo_exists()
{
utxo=$($bitcoin_cli gettxout $1 $2)
@@ -781,6 +803,7 @@ if [[ $1 == "just_in_time" ]]; then
fi
# try again, multiple jit openings should work without issues
new_blocks 3
+ wait_for_chain_tip bob
echo "carol pays alice again"
invoice=$($alice add_request 0.04 --lightning --memo "invoice2" | jq -r ".lightning_invoice")
success=$($carol lnpay $invoice | jq -r ".success")
Why this scored 15/100
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