test

Run tests for the React codebase.

Arguments:

• $ARGUMENTS: Channel, flags, and test pattern

Usage Examples:

• /test ReactFiberHooks – Run with source channel (default)
• /test experimental ReactFiberHooks – Run with experimental channel
• /test www ReactFiberHooks – Run with www-modern channel
• /test www variant false ReactFiberHooks – Test VARIANT=false
• /test stable ReactFiberHooks – Run with stable channel
• /test classic ReactFiberHooks – Run with www-classic channel
• /test watch ReactFiberHooks – Run in watch mode (TDD)

Release Channels:

• (default) – Source/canary channel, uses ReactFeatureFlags.js defaults
• experimental – Source/experimental channel with EXPERIMENTAL flags = true
• www – www-modern channel with VARIANT flags = true
• www variant false – www channel with VARIANT flags = false
• stable – What ships to npm
• classic – Legacy www-classic (rarely needed)

Instructions:

1. Parse channel from arguments (default: source)
2. Map to yarn command:
   • (default) → yarn test --silent --no-watchman <pattern>
   • experimental → yarn test -r=experimental --silent --no-watchman <pattern>
   • stable → yarn test-stable --silent --no-watchman <pattern>
   • classic → yarn test-classic --silent --no-watchman <pattern>
   • www → yarn test-www --silent --no-watchman <pattern>
   • www variant false → yarn test-www --variant=false --silent --no-watchman <pattern>
3. Report test results and any failures

Hard Rules:

1. Use –silent to see failures – This limits the test output to only failures.
2. Use –no-watchman – This is a common failure in sandboxing.

Common Mistakes:

• Running without a pattern – Runs ALL tests, very slow. Always specify a pattern.
• Forgetting both www variants – Test www AND www variant false for __VARIANT__ flags.
• Test skipped unexpectedly – Check for @gate pragma; see feature-flags skill.