feat(testing): add flashblocks-e2e testing tool #348

niran · 2026-01-11T06:35:15Z

Summary

Adds flashblocks-e2e binary for end-to-end regression testing of flashblocks RPC
Creates testing/e2e library crate with reusable test infrastructure
Includes 22 tests across 7 categories: blocks, call, receipts, logs, sanity, metering, contracts

Architecture

bin/flashblocks-e2e/     # Minimal CLI shim
testing/e2e/             # Reusable library
├── client.rs            # TestClient for RPC interactions
├── harness.rs           # FlashblockHarness for pending state testing
├── types.rs             # MeterBundle*, Flashblock* types
├── runner.rs            # Test execution + output formatting
└── tests/               # Test definitions

Usage

# Run all tests
flashblocks-e2e --rpc-url https://... --flashblocks-ws-url wss://...

# List tests
flashblocks-e2e --list

# Filter tests
flashblocks-e2e --filter "flashblock*"

# JSON output for CI
flashblocks-e2e --format json

Test plan

cargo check -p base-e2e -p flashblocks-e2e
cargo clippy -p base-e2e -p flashblocks-e2e -- -D warnings
Verified against live Base mainnet dev node (14/14 runnable tests pass)

Port the flashblocks-e2e end-to-end testing tool with a reusable library architecture: - bin/flashblocks-e2e/: minimal CLI shim (~70 lines) - testing/e2e/: reusable library with TestClient, FlashblockHarness, test runner, and 22 tests across 7 categories Test categories: blocks, call, receipts, logs, sanity, metering, contracts

cb-heimdall · 2026-01-11T06:35:19Z

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Establish naming pattern where testing crates include "testing" in the name for clarity.

* fix flashblocks timing and tests * formatting

Remove hardcoded recipient addresses from test files. The recipient must now be provided via --recipient CLI argument, and the tool aborts if recipient equals sender to prevent accidental self-transfers.

haardikk21

Some comments

Also a question more generally - what's the intention with this CLI? I may have missed the memo on this but is this something we're gonna run manually against dev nodes to try out things or something?

my prev understanding was its aiming to set the stage a bit for automated devnet-style testing of changes per-PR/pre-release, but then I don't really get the need for the CLI and instead have other things in mind that need to be addressed first.

haardikk21 · 2026-01-12T05:54:31Z

testing/e2e/src/tests/blocks.rs

+            Test {
+                name: "get_latest_block".to_string(),
+                description: Some("Verify we can retrieve the latest block".to_string()),
+                run: Box::new(|client| Box::pin(test_get_latest_block(client))),
+                skip_if: None,
+            },
+            Test {
+                name: "get_pending_block".to_string(),
+                description: Some("Verify we can retrieve the pending block".to_string()),
+                run: Box::new(|client| Box::pin(test_get_pending_block(client))),
+                skip_if: None,


non-blocking nit but this seems like the perfect use case for just definining a custom macro to get rid of these duplications throughout this crate

haardikk21 · 2026-01-12T05:55:20Z

testing/e2e/src/tests/blocks.rs

+fn skip_if_no_signer_or_recipient(client: &TestClient) -> Option<String> {
+    if !client.has_signer() {
+        Some("No PRIVATE_KEY configured".to_string())
+    } else if client.recipient().is_none() {
+        Some("No --recipient configured".to_string())
+    } else {
+        None
+    }
+}


this fn is present across all the different test files. can we just share this somewhere instead?

haardikk21 · 2026-01-12T06:05:17Z

testing/e2e/src/harness.rs

+            let json_str = decode_ws_message(&msg)?;
+
+            let flashblock: Flashblock =
+                serde_json::from_str(&json_str).wrap_err("Failed to parse flashblock message")?;
+
+            return Ok(flashblock);


Should we just use

node-reth/crates/shared/flashtypes/src/block.rs

Lines 29 to 48 in a5de9fa

impl Flashblock {

/// Attempts to decode a flashblock from bytes that may be plain JSON or brotli-compressed JSON.

pub fn try_decode_message(bytes: impl Into<Bytes>) -> Result<Self, FlashblockDecodeError> {

let text = Self::try_parse_message(bytes.into())?;

let payload: FlashblocksPayloadV1 =

serde_json::from_str(&text).map_err(FlashblockDecodeError::PayloadParse)?;

let metadata: Metadata = serde_json::from_value(payload.metadata.clone())

.map_err(FlashblockDecodeError::MetadataParse)?;

Ok(Self {

payload_id: payload.payload_id,

index: payload.index,

base: payload.base,

diff: payload.diff,

metadata,

})

}

or are we avoiding internal dependencies for some reason?

haardikk21 · 2026-01-12T06:07:14Z

testing/e2e/src/types.rs

+pub struct FlashblockBase {
+    /// Base fee per gas.
+    pub base_fee_per_gas: String,
+    /// Block number.
+    pub block_number: String,
+    /// Block timestamp.
+    pub timestamp: String,
+    /// Fee recipient address.
+    pub fee_recipient: String,
+    /// Gas limit.
+    pub gas_limit: String,
+    /// Parent block hash.
+    pub parent_hash: String,
+}
+
+/// Diff/delta for this flashblock.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct FlashblockDiff {
+    /// State root after this flashblock.
+    pub state_root: String,
+    /// Receipts root after this flashblock.
+    pub receipts_root: String,
+    /// Logs bloom filter.
+    pub logs_bloom: String,
+    /// Cumulative gas used.
+    pub gas_used: String,
+    /// Block hash (changes with each flashblock).
+    pub block_hash: String,
+    /// RLP-encoded transaction hex strings.
+    pub transactions: Vec<String>,
+    /// Withdrawals in this flashblock.
+    #[serde(default)]
+    pub withdrawals: Vec<serde_json::Value>,
+    /// Withdrawals root.
+    #[serde(default)]


these should just be coming from the flashtypes crate

cb-heimdall · 2026-01-12T06:12:25Z

Review Error for haardikk21 @ 2026-01-12 06:12:24 UTC
User failed mfa authentication, see go/mfa-help

refactor(testing): rename base-e2e to base-testing-e2e

ff803b0

Establish naming pattern where testing crates include "testing" in the name for clarity.

danyalprout pushed a commit that referenced this pull request Jan 11, 2026

Add flashblock timing configuration options (#348)

3403294

* fix flashblocks timing and tests * formatting

danyalprout pushed a commit that referenced this pull request Jan 11, 2026

Add flashblock timing configuration options (#348)

078b866

* fix flashblocks timing and tests * formatting

niran added 2 commits January 11, 2026 17:28

refactor(testing): require --recipient CLI arg for ETH transfer tests

2672969

Remove hardcoded recipient addresses from test files. The recipient must now be provided via --recipient CLI argument, and the tool aborts if recipient equals sender to prevent accidental self-transfers.

style(testing): apply nightly rustfmt

b7bf1c6

haardikk21 requested changes Jan 12, 2026

View reviewed changes

haardikk21 mentioned this pull request Jan 12, 2026

feat: create a system tests environment #357

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feat(testing): add flashblocks-e2e testing tool #348

feat(testing): add flashblocks-e2e testing tool #348

niran commented Jan 11, 2026

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cb-heimdall commented Jan 11, 2026 •

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	impl Flashblock {
	/// Attempts to decode a flashblock from bytes that may be plain JSON or brotli-compressed JSON.
	pub fn try_decode_message(bytes: impl Into<Bytes>) -> Result<Self, FlashblockDecodeError> {
	let text = Self::try_parse_message(bytes.into())?;

	let payload: FlashblocksPayloadV1 =
	serde_json::from_str(&text).map_err(FlashblockDecodeError::PayloadParse)?;

	let metadata: Metadata = serde_json::from_value(payload.metadata.clone())
	.map_err(FlashblockDecodeError::MetadataParse)?;

	Ok(Self {
	payload_id: payload.payload_id,
	index: payload.index,
	base: payload.base,
	diff: payload.diff,
	metadata,
	})
	}

feat(testing): add flashblocks-e2e testing tool #348

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niran commented Jan 11, 2026

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cb-heimdall commented Jan 11, 2026 •

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