How to test RBF on Testnet? I'd like to do RBF testing on testnet. I'd like to simulate a transaction with too-low fees, aka &quot;stuck&quot; transaction, and then RBF it in various ways.
Problem is, all testnet transactions are added to the next block due to mostly-empty mempool and 1 sat/B fee rate.
Is there a clever way to create a transaction that sits in the testnet mempool, which can be later mined after RBF?
Didn't the developers of RBF test their code on testnet?
There are 2 workarounds possible:

It takes few minutes for most of the transactions to be included in a block. So, you can prepare all the steps in advance and perform within couple of minutes before this transaction is confirmed.

Broadcast transactions with fee rate below 1 sat/vByte


Change Min Transaction Relay Fee in bitcoin.conf with minrelaytxfee=0.00000001
Either run multiple nodes on testnet with same configuration and add them using addnode or ignore this step.
Create a transaction with createrawtransaction, Enable RBF and specify fee rate below 1 sat/vByte with arguments &quot;replaceable&quot; : true and &quot;fee_rate&quot; : 0.5 in fundrawtransaction
Sign the transaction with signrawtransactionwithwallet
Broadcast the transaction with sendrawtransaction
Check the transaction details using https://chain.so/testnet/btc

Bump fee: bumpfee 42bb96fa5f5812cfd53695f679b69bccaf37fb4d49b78a650e05e0109d92f223
{
  &quot;txid&quot;: &quot;bac13170082c79033d37767e9180d676b05044acf90e41b1a992f76eda97f14e&quot;,
  &quot;origfee&quot;: 0.00000526,
  &quot;fee&quot;: 0.00005616,
  &quot;errors&quot;: [
  ]
}