• Tests in Spock (Groovy), not JUnit: src/test/groovy/graphql/
• No new dependencies (firm policy)
• No wildcard imports, no inner classes, no Optional
• Max 2 indent levels; early returns; extract methods to reduce nesting
• Immutable data classes w/ Builder: newFoo() factory, foo(value) setters, transform() method
• Use graphql.Assert not Objects.requireNonNull
• Use @Public/@Internal annotations — never package-private/protected
• @NullMarked on all public API classes; @NullUnmarked on their Builder classes; use @Nullable for nullable params/returns; NullAway enforced via ErrorProne
• Full style guide: coding-guidelines.md

./gradlew test

This runs tests on Java 25 only. Other JVM versions (11, 17, 21) require explicit tasks (e.g. testWithJava11).