fix: enable parallel execution for federation integration tests

[jensneuse]

Move mutable global state into per-Resolver instances so each FederationSetup gets isolated data. This eliminates the global mutex that serialized all tests and fixes the data race in subscription resolvers by copying products before mutation.

Summary by CodeRabbit

• Tests

  • Enabled parallel execution across federation integration tests, restructured setups to isolate state, and removed the previous build constraint so tests run with race detectors enabled.
  • Mutation tests now use isolated setups to avoid cross-test interference.

• Refactor

  • Replaced global test state with instance-scoped resolver state and factory-backed data initialization.
  • Removed global synchronization around test setup to allow concurrent execution.

Checklist

• I have discussed my proposed changes in an issue and have received approval to proceed.
• I have followed the coding standards of the project.
• Tests or benchmarks have been added or updated.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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📝 Walkthrough

Walkthrough

Move package-level test and fixture globals into resolver instances and factory functions, remove synchronized setup teardown, add parallel test execution (t.Parallel()), and make products/reviews resolvers stateful with configurable pricing/update behavior.

Changes

Cohort / File(s)	Summary
Test Parallelization execution/engine/federation_integration_static_test.go, execution/engine/federation_integration_test.go	Enable parallel tests (t.Parallel()), remove race-only build constraint, introduce shared read-only setup and isolated mutation setup to avoid port/state contention.
Products — Resolver & Handler execution/federationtesting/products/graph/resolver.go, execution/federationtesting/products/graph/handler.go	Replace empty Resolver with stateful struct (products, randomness, price bounds, currentPrice, updateInterval, mutex); handler now constructs and injects the populated Resolver.
Products — Data & Resolvers execution/federationtesting/products/graph/products.go, execution/federationtesting/products/graph/entity.resolvers.go, execution/federationtesting/products/graph/schema.resolvers.go	Remove package-level globals; add newProducts() factory; resolver methods now use r.products, operate on copied product pointers for streams, and read pricing/update config from the resolver.
Reviews — Resolver & Handler execution/federationtesting/reviews/graph/resolver.go, execution/federationtesting/reviews/graph/handler.go	Expand Resolver to hold reviews and attachments; handler initializes and passes the populated Resolver to the schema.
Reviews — Data & Resolvers execution/federationtesting/reviews/graph/reviews.go, execution/federationtesting/reviews/graph/attachments.go, execution/federationtesting/reviews/graph/schema.resolvers.go	Replace package-level reviews/attachments with newReviews()/newAttachments() factories; resolvers updated to use r.reviews/r.attachments.
Infrastructure & Cleanup execution/federationtesting/gateway/main.go, execution/federationtesting/util.go, execution/federationtesting/products/graph/variables.go	Remove global mutex around FederationSetup (unsynchronized init/teardown), delete now-unused variables.go, and replace ws.DefaultHTTPUpgrader with an explicit ws.HTTPUpgrader{Header: ...} literal.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

Possibly related PRs

• chore: enable the tparallel lint check #1305: Similar addition of t.Parallel() markers to test suites to enable parallel test execution.
• fix: execution tests, disable test cache for execution #1206: Overlapping edits to execution/engine/federation_integration_test.go (test restructuring and expectations adjustments).

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly describes the main objective of the changeset: enabling parallel execution for federation integration tests.
Merge Conflict Detection	✅ Passed	✅ No merge conflicts detected when merging into master

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch jensneuse/improve-execution-test-speed

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[coderabbitai]

Actionable comments posted: 2

🤖 Fix all issues with AI agents

In `@execution/federationtesting/products/graph/schema.resolvers.go`:
- Line 24: The TopProducts resolver currently returns
r.products[:len(r.products)-1] which will panic on empty slices and ignores the
first parameter; update the TopProducts function to first guard for empty
r.products (return nil, nil or empty slice) and then compute an upper bound as
min(len(r.products), first) (also handle non-positive first by returning empty)
before slicing (e.g., return r.products[:bound], nil). Ensure you reference and
use r.products and the first parameter in TopProducts to safely clamp the slice.
- Around line 35-48: The subscription goroutine mutates shared resolver state
r.currentPrice without synchronization; add a sync.Mutex field (e.g., priceMu
sync.Mutex) to the Resolver type and use priceMu.Lock()/priceMu.Unlock() around
every read/write of r.currentPrice in the UpdatedPrice handler (the section that
sets p.Price = r.currentPrice and increments r.currentPrice), and ensure the
sync package is imported so concurrent subscriptions cannot race on
currentPrice.

🧹 Nitpick comments (1)

execution/federationtesting/products/graph/handler.go (1)

19-19: Global websocketConnections counter may produce misleading values in parallel tests.

The websocketConnections atomic counter remains a package-level variable. While atomic operations prevent data races, parallel tests sharing this counter will see aggregated values from all concurrent test instances. Line 34's Store(0) reset could also clear counts from other parallel tests mid-execution.

If WebsocketConnectionsHandler is only used for debugging and not asserted in tests, this is acceptable. Otherwise, consider moving the counter into the resolver or handler struct for isolation.

Also applies to: 34-34

[coderabbitai]

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@execution/federationtesting/products/graph/schema.resolvers.go`:
- Around line 42-57: The case branch can panic when r.products is empty or has
one element; add a guard using n := len(r.products) and if n == 0 { continue }
before accessing r.products, and when picking a random product use idx :=
rand.Intn(n) (rand.Intn requires >0) so it works for n==1 (returns 0); replace
direct uses of r.products[len(r.products)-1] and rand.Intn(len(r.products)-1)
with r.products[n-1] and r.products[idx] respectively, preserving the Price
mutation logic (use p := *product, set p.Price, send via updatedPrice) and keep
synchronization around r.currentPrice with r.priceMu as before.