test(e2e): spec cross-chain swaps

[shoom3301]

What changed

• Adds bridge-provider mocks: Bungee (destination-token list, intermediate-token list, quote fixtures) and NEAR Intents (attestation, destination-token list, quote fixtures), a fixture-loading helper, and a socket verifier (+ test) that validates mocked WebSocket bridge-status updates.
• Adds nestedRpcCallRegistry.test.ts, covering the RPC-call tracking shared across bridge specs.
• Adds cross-chain-swaps.spec.ts — 8 @smoke Playwright tests covering: the cross-chain UI's entry point from the Swap form, a NEAR-provider swap, a Bungee-provider swap, an ETH-flow (native ETH) source sent cross-chain, a swap to Solana (SOL/SPL destination), a swap to Bitcoin (BTC destination), and two calculation-parity checks (swap form "Receive" vs. bridge widget "Expected to receive", and bridge "Min. to deposit" vs. swap "Min. to receive").

Why

• Extends the e2e suite to the bridging/cross-chain flow — the highest-complexity trade path (multiple bridge providers, non-EVM destinations, extra calculation surfaces) — using the mock-wallet/API infrastructure from PR #8035 and the NEAR Intents signature bypass and locator hooks from PR #8036.

QA Testing

Reviewer note:

• Test-only change (new spec + mock/fixture files, no production code); the smoke CI check is the verification for this PR.

Developer verification:

• pnpm e2e:smoke (or pnpm --filter @cowprotocol/cowswap-e2e-pw exec playwright test cross-chain-swaps.spec.ts) runs the new spec locally.

Preview URLs

Surface	URL
swap-dev - branch preview URL	https://swap-dev-git-e2e-tests-p4-cowswap-dev.vercel.app
explorer-dev - branch preview URL	https://explorer-dev-git-e2e-tests-p4-cowswap-dev.vercel.app
widget-configurator - branch preview URL	https://widget-configurator-git-e2e-tests-p4-cowswap-dev.vercel.app
storybook - branch preview URL	https://storybook-git-e2e-tests-p4-cowswap-dev.vercel.app

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
cowfi	Ready	Preview	Aug 28, 2026 12:03pm
explorer-dev	Ready	Preview	Aug 28, 2026 12:03pm
storybook	Ready	Preview	Aug 28, 2026 12:03pm
swap-dev	Ready	Preview	Aug 28, 2026 12:03pm
widget-configurator	Ready	Preview	Aug 28, 2026 12:03pm

2 Skipped Deployments

Project	Deployment	Actions	Updated (UTC)
cosmos	Ignored		Aug 28, 2026 12:03pm
sdk-tools	Ignored	Preview	Aug 28, 2026 12:03pm

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[Danziger]

⚠️ AI Review (Cursor Grok 4.6, worked 8m): [BLOCKING] CS-310/CS-311 can stay on Bungee after setFlag

Finding: [BLOCKING] Provider switches still need page.reload() — CS-310/CS-311 do not do that

• Location: apps/cowswap-e2e-tests/src/tests/cross-chain-swaps.spec.ts:105 (comment), 147, and the CS-310/CS-311 loops at 554 / 601
• This one is important: the comment describes a live featureFlagsUpdate path that is not implemented, and the parity tests can pass without ever leaving Bungee.

Verified against current code:

• installLaunchDarkly.setFlag only calls context.addInitScript. That runs on the next document load, not on the already-open page.
• useFeatureFlags (libs/common-hooks/src/useFeatureFlags.ts) reads window.__COWSWAP_E2E_FEATURE_FLAGS__ inside useMemo(..., [flags]). There is no featureFlagsUpdate listener, so even a live window write would not update BridgeProvidersUpdater.
• wallet.openApp / openCrossChainSwap use page.goto('/#/...'). After the first load that is a hash-only navigation, so the new init script does not run.
• Receipt: e2e AGENTS.md already says a mid-test setFlag needs page.reload() after the new hash is in the address bar.

CS-285 reloads before the Near half, so that test does switch. CS-310/CS-311 call configureProviders again and only assert amounts, not bridgeStopTitle('Near Intents'), so a stuck Bungee quote still satisfies them.

Suggested fix

• Drop the featureFlagsUpdate claim. Match the AGENTS.md reload rule.
• After each configureProviders in CS-310/CS-311 (and anywhere else that switches providers on an already-loaded page), await swapPage.page.reload() — same pattern as CS-285.
• Assert the active provider in those loops, e.g. bridgeStopTitle('Bungee'|'Near Intents'), so a missed reload fails the test instead of silently testing Bungee twice.

Review scope and related context

This is a reply on the existing reload/setFlag thread, not a second top-level comment.

Not repeated here:

• configureProviders takes unused rpcProxy and its comment still says it stubs Bungee's on-chain check; installSocketVerifier already does that globally.
• CS-287 flaked once in smoke (expectOrderToBePosted 10s timeout) then passed on retry; CS-68 also flaked in that run, so this looks like suite load rather than a separate provider-switch bug.

🤖 Prompt for AI agents

Verify this finding against current code. Fix only if still valid, keep the change minimal, and validate with the targeted tests.

Context:
- apps/cowswap-e2e-tests/src/tests/cross-chain-swaps.spec.ts (openCrossChainSwap comment ~105, CS-285 reload ~148, CS-310 ~554, CS-311 ~601)
- apps/cowswap-e2e-tests/src/mocks/launchDarkly.ts setFlag is addInitScript-only
- libs/common-hooks/src/useFeatureFlags.ts memos on LaunchDarkly flags only; no featureFlagsUpdate event
- Failure mode: mid-test setFlag + hash goto does not change bridgingSdk providers; CS-310/CS-311 can pass while still on Bungee
- Expected fix: reload after configureProviders when the page is already loaded; assert bridgeStopTitle per provider in the loops; align the comment with AGENTS.md
- Validate: pnpm --filter @cowprotocol/cowswap-e2e-pw exec playwright test cross-chain-swaps.spec.ts -g "CS-310|CS-311|CS-285"

Generated using the pr-review skill from the CoW Protocol skills repo.

[shoom3301]

Confirmed, this was a real bug — fixed:

• [CS-310]/[CS-311]'s loops now reload after configureProviders (skipped on the first iteration, since nothing has navigated yet), same pattern [CS-285] already uses.
• Both loops now assert bridgeStopTitle(...) for the intended provider each iteration, so a missed reload fails the test instead of silently re-testing Bungee twice.
• Dropped the false featureFlagsUpdate claim from openCrossChainSwap's doc comment and replaced it with the actual mechanism (why a hash-only nav can't pick up new flags) plus a pointer to AGENTS.md's reload rule.
• Left the unused rpcProxy param on configureProviders alone, per your own note that it's already known and not part of this finding.

Verified with playwright test cross-chain-swaps.spec.ts — all 8 tests pass, including [CS-310]/[CS-311] now genuinely exercising Near Intents on their second iteration (the new bridgeStopTitle assertion would have caught it otherwise).