Building Testing Strategy for Blockchain Protocols and Dapps

An up-to-date, actionable blueprint for testing modern blockchain systems after Dencun, ERC‑4337 adoption, and shifting testnets—tailored for startups and enterprises that need provable reliability, not platitudes. This post translates 2024–2025 protocol changes into concrete test plans, tools, and CI gates you can adopt today.

Why your Web3 test strategy must change (2024–2025)

• Ethereum’s Dencun (Cancun/Deneb) upgrade activated on March 13, 2024, introduced blob-carrying transactions (EIP‑4844) with a separate blob fee market and ~18‑day data availability window—fundamentally changing how rollups post data and how you must test data availability and costs. (ethereum.org)
• Transient storage (EIP‑1153) and the BLOBBASEFEE opcode (EIP‑7516) arrived with Dencun support in Solidity 0.8.24+, adding new state and fee-access patterns your tests should explicitly cover. (soliditylang.org)
• Ethereum testnets rotated: Holesky support ended in September 2025; Hoodi is now the protocol/staking testnet, and Sepolia remains the default application testnet. Your pipelines and faucets must align with this migration. (blog.ethereum.org)
• ERC‑4337 account abstraction matured with shared mempools, conformance tests, and multiple bundlers—meaning you need deterministic bundler simulations and paymaster tests in CI. (bundlers.erc4337.io)
• L2 stacks upgraded: OP Stack introduced permissionless fault proofs on OP Sepolia; Arbitrum’s Nitro dev/test nodes and Base Sepolia releases track L1 changes (e.g., Fusaka-era requirements for blob storage on beacon clients). Integration tests must assert withdrawal challenge/fault-proof flows and node compatibility. (blog.oplabs.co)

The net: your test plan now has to validate blob economics, transient state behavior, testnet choices, AA flows, and L2-specific proof/bridge semantics—not just Solidity unit tests.

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A practical test pyramid for blockchain (2025 edition)

Think “risk-driven” rather than “unit-test-only.” Here’s a pyramid that maps to modern chains:

1. Developer-local and unit tests

• Solidity/Rust/Python unit tests with fast local nodes.
• Gas snapshots and reentrancy/authorization checks.
• Static analyzers and property annotations run on every commit.
  Tools: Foundry (forge/anvil), Hardhat, Slither, Scribble, cargo test (CosmWasm), solana-program-test. (getfoundry.sh)

1. Property-based and invariant testing

• State- and sequence-level properties, under fuzzing & symbolic engines.
  Tools: Foundry invariants/fuzzing and cheatcodes; Echidna; Halmos for symbolic testing. (learnblockchain.cn)

1. Protocol- and integration tests

• ERC‑4337 bundler conformance, paymasters, and mempool behavior.
• Rollup bridge, withdrawal, and proof flows.
• Cross-contract and cross-module tests (CosmWasm cw‑multi‑test). (github.com)

1. Environment/chaos and performance tests

• Shadow forks or Virtual TestNets with production state, blob fee spikes, sequencer downtime simulations, rate limit and RPC failover.
  Tools: Tenderly Virtual TestNets (replacement for deprecated Forks), Arbitrum Nitro dev/test nodes, OP Sepolia for proofs. (tenderly.co)

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Choose environments that match 2025 reality

• Sepolia + Hoodi: use Sepolia for dapp/application testing; use Hoodi for validator/protocol testing. If you still have Holesky jobs, retire them—Holesky support ended September 30, 2025. (ethereum.org)
• OP Sepolia: primary OP Stack testnet with feature-complete fault proofs—use it to test withdrawal/fault-proof flows before mainnet. (blog.oplabs.co)
• Arbitrum Nitro dev/test nodes: spin up a single-node dev chain or a full local L1/L2 simulation (nitro-testnode) with predefined keys and RPC endpoints for repeatable CI. (docs.arbitrum.io)
• Base Sepolia: keep node releases in sync with L1 testnet upgrades; some versions require beacon clients to store blob data (e.g., supernode flag) post-Fusaka on Sepolia—mirror this in integration tests. (github.com)
• ZKsync: use anvil‑zksync and the Hardhat/Foundry plugins to run EraVM-local tests and forks; respect ZKsync reserved address ranges in fuzz tests. (docs.zksync.io)
• Tenderly Virtual TestNets: for long‑running, state‑synced, multi‑chain staging with unlimited faucets and state manipulation—use custom chain IDs (e.g., 73571 prefix) to avoid replay. (tenderly.co)

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Tooling that actually catches modern bug classes

• Foundry for fast unit/invariant tests, fuzzing, gas snapshots, and mainnet/L2 forking via Anvil; use cheatcodes (vm.prank, vm.assume, vm.roll, etc.) to deterministically model reentrancy, time, and roles. (getfoundry.sh)
• Slither for static analysis (detectors, custom rules, upgradeability helpers) integrated in CI. (github.com)
• Scribble for inline specifications and runtime verification; pair with fuzzers to turn properties into executable checks. (diligence.consensys.io)
• Echidna for property fuzzing driven by invariants; integrates with Slither for pre-analysis. (github.com)
• Halmos for symbolic testing built around existing Foundry tests; useful for stateful invariants and path exploration beyond random fuzzing. (github.com)
• Certora Prover for formal verification of critical components, with CVL specs, open-source Prover, and CI automation. Use vacuity/spec sanity checks to avoid false confidence. (docs.certora.com)

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Concrete test plans, by component

1) Smart contracts on EVM (post‑Dencun)

What to test beyond typical unit tests:

• Blob-aware logic: if your protocol or oracle accounts for L2 blob costs, assert correct reading of BLOBBASEFEE (EIP‑7516) and fallbacks when blob capacity is low; add tests for price spikes and zero-blob blocks. (eips.ethereum.org)
• Transient storage use: test reentrancy guards and “per‑transaction” state using TLOAD/TSTORE through inline assembly in Solidity 0.8.24+; include revert scenarios and nested call frames. (soliditylang.org)
• SELFDESTRUCT behavior changes and MCOPY efficiency: ensure legacy assumptions hold after Cancun EVM semantics. (soliditylang.org)

Foundry example (transient storage guard):

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

contract ReentrancyTS {
    // lock in transient storage at key 0x0
    function _lock() internal {
        assembly { tstore(0x0, 1) }
    }
    function _unlock() internal {
        assembly { tstore(0x0, 0) }
    }
    modifier noReenter() {
        assembly {
            if eq(tload(0x0), 1) { revert(0,0) }
        }
        _lock();
        _;
        _unlock();
    }
}

• Invariant tests should assert that no externally callable function can observe lock=1 at function exit, even on deep call chains and on revert paths. Run with Foundry invariant runner and Halmos for symbolic exploration.

2) ERC‑4337 account abstraction

• Run bundler conformance tests (v0.8) against your chosen bundler; pin EntryPoint version and address in tests; simulate

  simulateValidation

  paths and full

  handleOps

  bundles. (github.com)
• Test paymasters (token‑sponsored gas) across edge cases: ERC‑20 transfer failures, allowance races, and UserOp gas overstatements (10% penalty rules in EntryPoint v0.7). (github.com)
• Chaos tests: drop single bad UserOp in a bundle and ensure bundler excludes it; verify shared mempool constraints (ERC‑7562‑style rules) via spec tests. (docs.erc4337.io)

3) L2 rollups, blobs, bridges, and proofs

• Arbitrum: local Nitro dev node for app tests, and nitro‑testnode for full L1/L2 messaging tests, including retryables and delayed inbox. Assert correct behavior under sequencer downtime. (docs.arbitrum.io)
• OP Stack: test withdrawals and fault‑proof disputes on OP Sepolia; measure latency and failure paths pre‑mainnet. (blog.oplabs.co)
• Base Sepolia: adjust tests for L1 testnet upgrades (e.g., beacon client blob storage configuration) to avoid false-positive failures on blob reads. (github.com)
• Blob fee dynamics: regression tests that assert total cost calculations switch from calldata to blobs when available, and back under congestion. Track blob retention (~4096 epochs ≈ 18 days) in your data availability monitors. (ethereum.org)

4) Upgradeability and governance

• Use OpenZeppelin Upgrades (Hardhat/Foundry plugins) to enforce storage layout compatibility in CI; maintain a manifest in VCS; test UUPS/transparent/beacon flows, plus “break‑glass” via timelock and Safe. (docs.openzeppelin.com)
• On zk/Era chains, use the zk‑aware upgrade plugins, and test proxy patterns with their specific compilers and manifests. (docs.zksync.io)

5) ZK circuits and zkVM integrations

• Circom circuits: unit test with

  circom_tester

  , verify witness correctness, then generate proofs with snarkjs; include negative tests for malformed witnesses. (docs.circom.io)
• ZKsync Era: anvil‑zksync for local tests,

  hardhat-zksync-solc

  for compilation; ensure fuzzers avoid reserved address ranges and that forks (era_test_node) cover real liquidity paths (e.g., Uniswap swaps). (docs.zksync.io)
• Keep an eye on zkVM testing research—soundness/completeness testing is emerging; integrate fixes suggested by tool findings where practical. (arxiv.org)

6) Cosmos SDK and CosmWasm

• Use the Cosmos SDK simulator (

  SimApp

  ) to fuzz modules with randomized messages/params and detect halt conditions before mainnet. (docs.cosmos.network)
• For CosmWasm contracts, use

  cw-multi-test

  to simulate multi-contract interactions off‑chain; unit test messages, replies, and IBC hooks without spinning full nodes. (cosmwasm.cosmos.network)

7) Solana programs

• Use

  solana-program-test

  to spin an in‑process bank and test SBF programs with BanksClient, including compute budget and priority fee behavior; keep crates aligned with the current Agave/Solana SDK. (docs.rs)

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CI/CD blueprint with modern gates

Recommended pipeline (GitHub Actions outline):

• Static and build gates

  • slither . (fail on high/med)
  • solidity 0.8.27+ build (evm‑version=cancun); run typechain/ABIs
  • oz upgrades validate (storage layout check)
    Tools: Slither, OpenZeppelin Upgrades Core. (github.com)

• Unit and property tests

  • forge test -vvv (gas snapshots); hardhat test if applicable
  • forge test --ffi for scriptable fixtures; foundry invariants (depth/runs tuned)
  • echidna runs for critical invariants; halmos over selected targets nightly
    Tools: Foundry, Hardhat, Echidna, Halmos. (learnblockchain.cn)

• Integration tests

  • anvil --fork (L1/L2) + playwright/backend tests
  • Arbitrum nitro‑devnode or nitro‑testnode for cross‑layer tests
  • OP Sepolia tests for withdrawals/fault proofs
    Tools: Anvil, Nitro dev/test nodes, OP Sepolia. (getfoundry.sh)

• Staging with production data

  • Provision Tenderly Virtual TestNets per PR (unique chain IDs, unlimited faucets); run end‑to‑end flows and share explorers for QA sign‑off. (docs.tenderly.co)

• Formal verification (gated by criticality)

  • Certora Prover against CVL specs for invariants (no-burn-without-mint, debt ratio bounds, role gating). (docs.certora.com)

• AA conformance

  • Run ERC‑4337 bundler spec tests for chosen bundler; simulate

    UserOperation

    failure modes. (github.com)

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Non‑functional tests you should not skip

• Gas/cost regression: assert max gas for top 20 user paths; assert blob vs calldata cost switches; budget tests for BLOBBASEFEE spikes. (eips.ethereum.org)
• Data availability: verify watchers can retrieve blob data within the ~18‑day window and that your L2 exit proofs don’t rely on pruned data. (ethereum.org)
• Chaos and failover:
  • Drop L2 sequencer for N minutes, then replay backlog; verify idempotency and user-facing messaging.
  • RPC rate‑limit simulation: ensure exponential backoff and provider failover.
• Upgrade rehearsals: dry‑run upgrades on Virtual TestNet with Safe + timelock flows; validate storage layout and role transfers via OpenZeppelin plugins. (docs.openzeppelin.com)

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Worked examples

1. Testing a blob‑aware rollup costing module

• Unit: compute cost using

  block.blobbasefee

  and fallback to calldata pricing when no blobs are present; assert both branches.
• Integration: on a forked environment, set blob base fee extremes and assert fee bounds and events. (soliditylang.org)

1. ERC‑4337 paymaster

• Property: “sponsor gas only when policy X holds” in Scribble; fuzz with Echidna to find violations. (diligence.consensys.io)
• Integration: submit mixed bundles (valid/invalid UserOps) on a local bundler; assert bundle acceptance, refund paths, and replay protections. (docs.erc4337.io)

1. Arbitrum cross‑layer message

• Local nitro‑testnode: send L2→L1 message, simulate delay, finalize; assert retryables and gas estimation are consistent across restarts. (docs.arbitrum.io)

1. CosmWasm DEX module

• cw‑multi‑test: multi‑contract swaps, fee routing, and IBC mock callbacks; fuzz random trade sequences for invariant “no free value creation.” (cosmwasm.cosmos.network)

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“Go‑live” acceptance criteria we recommend

• 100% of critical paths covered by unit tests; zero high severity Slither findings; gas budgets within SLOs. (github.com)
• Invariant/property suites run nightly with >100K total executions across Foundry invariants, Echidna, and Halmos; no unresolved counterexamples. (github.com)
• Upgrades rehearsed end‑to‑end on a long‑lived Virtual TestNet with governance flows; storage layout diffs approved. (tenderly.co)
• ERC‑4337 flows: bundler conformance tests pass; paymaster limits enforced; replay and simulation checks in place. (github.com)
• L2 bridges/proofs: OP Sepolia and Nitro local tests green; blob‑window DA monitors alerting configured. (blog.oplabs.co)

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Emerging best practices we see working

• Prefer Hoodi/Sepolia alignment and retire Holesky jobs; keep a matrix that explicitly maps what runs where (dapps on Sepolia, validators on Hoodi). (blog.ethereum.org)
• Use Tenderly Virtual TestNets to create per‑PR, state‑synced staging with replay‑safe chain IDs; integrate GitHub Actions to spin them up/down for parallel suites. (docs.tenderly.co)
• Treat EIP‑1153 features deliberately: only opt into transient storage with clear invariants and tests for nested calls and reverts; avoid subtle reentrancy traps. (eips.ethereum.org)
• For ZK, keep circuits small and unit‑tested; add malicious-witness tests; on EraVM, enforce address constraints during fuzz to avoid false failures. (docs.circom.io)
• For AA, pin EntryPoint versions and bundler RPCs, and run the official spec tests regularly to catch breaking changes in the mempool or RPCs. (github.com)

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The 7Block Labs checklist (cut and ship)

• Networks: Using Sepolia for app tests, Hoodi for validator/protocol; OP Sepolia and Nitro test nodes configured. (ethereum.org)
• Dencun readiness: tests for BLOBBASEFEE and transient storage; calldata vs blob fee fallbacks. (eips.ethereum.org)
• Tooling: Foundry+Anvil, Slither, Scribble, Echidna, Halmos, Certora; CI executing all. (getfoundry.sh)
• AA: bundler spec tests passing; paymaster policies enforced; simulation-based prechecks. (github.com)
• L2: withdrawal/fault-proof tests on OP Sepolia; cross-layer on Nitro local; blob DA monitor within 18‑day window. (blog.oplabs.co)
• Upgrades: OZ storage layout checks; rehearsed upgrades on Virtual TestNets; governance execution verified. (docs.openzeppelin.com)

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Final word

Protocols and dapps that pass today’s tests are those that simulate tomorrow’s conditions: blob fee turbulence, AA mempools, proof systems, and rotating testnets. If you want help turning this blueprint into a living CI system with measurable risk reduction, 7Block Labs can stand up the environments, codify the properties, and wire the gates—so your mainnet day is just another green build.