Make mining more flexible in `bdk_testenv` #2100

evanlinjin · 2026-01-24T08:34:39Z

Description

Add mine_block to bdk_testenv::Env with custom timestamp and coinbase address. This allows us to test timelocked transactions.

Changelog notice

Added
- `mine_block` method to `bdk_testenv::Env` with custom `MineParams`. Blocks can be mined with no transactions, contain custom timestamp and custom coinbase address.
- `min_time_for_next_block` and `get_block_template` helper methods.

Checklists

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I followed the contribution guidelines

New Features:

I've added tests for the new feature
I've added docs for the new feature

oleonardolima · 2026-01-24T13:20:23Z

@evanlinjin I'd suggest you start working on this on top of #1826, as we're migrating to corepc library/API.

evanlinjin · 2026-01-25T09:49:51Z

@evanlinjin I'd suggest you start working on this on top of #1826, as we're migrating to corepc library/API.

Good point. I'll do so once that PR is merged. I would like to test this against bdk-tx right now and that's using the old bdk_testenv (for testing MTP).

oleonardolima

utACK 9d7f859

Overall looks good. I left a few comments that might help with removing some decoding done here, didn't tried the changes yet though.

crates/testenv/src/lib.rs

oleonardolima · 2026-02-05T21:14:13Z

crates/testenv/src/lib.rs

+                bdk_chain::bitcoin::script::Builder::new()
+                    .push_int(bt.height as i64)
+                    .push_opcode(bdk_chain::bitcoin::opcodes::OP_0)
+                    .into_script()


question: shouldn't this one also have the coinbase_aux values ?

I think this whole coinbase_scriptsig codeblock could be reworked, maybe even be extracted to a helper fn.

Woops, I over-relied on Claude here.

@oleonardolima Fixed it. Let me know what you think.

…dress Refactor block mining in `TestEnv` to use `getblocktemplate` RPC properly: - Add `MineParams` struct to configure mining (empty blocks, custom timestamp, custom coinbase address) - Add `mine_block()` method that builds blocks from the template with proper BIP34 coinbase scriptSig, witness commitment, and merkle root - Add `min_time_for_next_block()` and `get_block_template()` helpers - Refactor `mine_empty_block()` to use the new `mine_block()` API - Include mempool transactions when `empty: false`

oleonardolima · 2026-02-11T17:09:28Z

crates/testenv/src/lib.rs

+    /// Get the minimum valid timestamp for the next block.
+    pub fn min_time_for_next_block(&self) -> anyhow::Result<u32> {
+        Ok(self.get_block_template()?.min_time)
+    }


nit: currently it's only being used on the tests, is it really needed ? I mean, the same can be achieved directly calling the getblocktemplate.

oleonardolima · 2026-02-11T17:13:03Z

crates/testenv/src/lib.rs

+        let coinbase_scriptsig = {
+            let mut script = build_coinbase_scriptsig(&bt, false);
+            // Ensure scriptSig is at least 2 bytes (pad with OP_0 if needed)
+            if script.len() < 2 {
+                script = build_coinbase_scriptsig(&bt, true);
+            };
+            script


nit: it's only being used here, so the padding could be handled directly, but it's not a blocker though.

What do you mean?

oleonardolima · 2026-02-11T17:21:30Z

crates/testenv/src/lib.rs

+        let coinbase_outputs = if params.empty {
+            let tx_fees: Amount = bt
+                .transactions
+                .iter()
+                .map(|tx| tx.fee.to_unsigned().expect("fee must be positive"))
+                .sum();
+            let value = bt
+                .coinbase_value
+                .to_unsigned()
+                .expect("coinbase_value must be positive")
+                - tx_fees;
+            vec![TxOut {
+                value,
+                script_pubkey: params.address_or_anyone_can_spend(),
+            }]
+        } else {
+            core::iter::once(TxOut {
+                value: bt
+                    .coinbase_value
+                    .to_unsigned()
+                    .expect("coinbase_value must be positive"),
+                script_pubkey: params.address_or_anyone_can_spend(),
+            })
+            .chain(
+                bt.default_witness_commitment
+                    .as_ref()
+                    .map(|s| -> Result<_, HexToBytesError> {
+                        Ok(TxOut {
+                            value: Amount::ZERO,
+                            script_pubkey: ScriptBuf::from_hex(s)?,
+                        })
+                    })
+                    .transpose()?,
+            )
+            .collect()


question: was this created by claude, or there's an specific reason you need this ?

Which part are you referring to exactly? It's handy to have the ability to mine empty blocks.

github-project-automation bot added this to BDK Chain Jan 24, 2026

evanlinjin force-pushed the feature/testenv-mine-with-timestamp branch 2 times, most recently from 46db014 to b91363e Compare January 24, 2026 12:49

evanlinjin force-pushed the feature/testenv-mine-with-timestamp branch from b91363e to 70bca59 Compare January 24, 2026 13:30

evanlinjin self-assigned this Jan 25, 2026

evanlinjin force-pushed the feature/testenv-mine-with-timestamp branch from 70bca59 to 8a31d1f Compare January 25, 2026 09:48

evanlinjin force-pushed the feature/testenv-mine-with-timestamp branch 5 times, most recently from f776d50 to 9d7f859 Compare January 28, 2026 14:57

evanlinjin marked this pull request as ready for review January 28, 2026 14:58

oleonardolima self-requested a review January 31, 2026 02:50

oleonardolima moved this to Needs Review in BDK Chain Jan 31, 2026

oleonardolima added this to the Chain 0.24.0 milestone Jan 31, 2026

oleonardolima reviewed Jan 31, 2026

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evanlinjin force-pushed the feature/testenv-mine-with-timestamp branch from 9d7f859 to 2d3b817 Compare February 4, 2026 15:16

evanlinjin requested a review from oleonardolima February 5, 2026 01:20

oleonardolima reviewed Feb 5, 2026

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evanlinjin force-pushed the feature/testenv-mine-with-timestamp branch from 2d3b817 to 9620a7d Compare February 6, 2026 06:44

evanlinjin requested a review from oleonardolima February 6, 2026 06:45

oleonardolima reviewed Feb 11, 2026

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Make mining more flexible in bdk_testenv #2100

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Description

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oleonardolima commented Jan 24, 2026

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evanlinjin commented Jan 25, 2026

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Make mining more flexible in `bdk_testenv` #2100

Make mining more flexible in `bdk_testenv` #2100

evanlinjin commented Jan 24, 2026 •

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