@facebook/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.